(19)
(11)EP 2 573 841 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
27.11.2019 Bulletin 2019/48

(21)Application number: 12181559.1

(22)Date of filing:  23.08.2012
(51)International Patent Classification (IPC): 
H01M 4/04(2006.01)
H01M 10/0525(2010.01)
H01M 4/131(2010.01)
H01M 4/587(2010.01)
H01M 4/36(2006.01)
H01M 4/58(2010.01)
H01M 4/134(2010.01)
H01M 4/485(2010.01)
H01M 4/133(2010.01)
H01M 4/1391(2010.01)
H01M 4/48(2010.01)
H01M 4/02(2006.01)

(54)

Electrode active material, electrode comprising the same, lithium battery comprising the electrode, and method of preparing the electrode active material

Elektrodenaktivmaterial, Elektrode damit, Lithiumbatterie mit der Elektrode und Verfahren zur Herstellung des Elektrodenaktivmaterials

Matériau actif d'électrode, électrode le comprenant, batterie au lithium comprenant l'électrode et procédé de préparation du matériau actif d'électrode


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 23.09.2011 KR 20110096374
18.06.2012 KR 20120065166

(43)Date of publication of application:
27.03.2013 Bulletin 2013/13

(73)Proprietor: Samsung Electronics Co., Ltd.
Suwon-si, Gyeonggi-do, 443-742 (KR)

(72)Inventors:
  • SHON Jeong-kuk
    449-712 Gyeonggi-do (KR)
  • CHOI Jae-man
    449-712 Gyeonggi-do (KR)
  • HWANG Seung-sik
    449-712 Gyeonggi-do (KR)
  • KWON Moon-seok
    449-712 Gyeonggi-do (KR)
  • SONG Min-sang
    449-712 Gyeonggi-do (KR)
  • KIM Myun-hoon
    449-712 Gyeonggi-do (KR)
  • KIM Ji-man
    449-712 Gyeonggi-do (KR)
  • PARK Gwi-ok
    449-712 Gyeonggi-do (KR)

(74)Representative: Elkington and Fife LLP 
Prospect House 8 Pembroke Road
Sevenoaks, Kent TN13 1XR
Sevenoaks, Kent TN13 1XR (GB)


(56)References cited: : 
WO-A2-2004/049473
US-A1- 2006 234 127
US-A1- 2004 234 859
  
  • YUAN L ET AL: "Nano-structured SnO2-carbon composites obtained by in situ spray pyrolysis method as anodes in lithium batteries", JOURNAL OF POWER SOURCES, ELSEVIER SA, CH, vol. 146, no. 1-2, 26 August 2005 (2005-08-26), pages 180-184, XP027756410, ISSN: 0378-7753 [retrieved on 2005-08-26]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND OF THE INVENTION



[0001] Aspects of the present disclosure relate to electrode active materials, electrodes including the electrode active materials, lithium batteries including the electrodes, and methods of preparing the electrode active materials.

[0002] A representative example of a negative active material that is used in an electrochemical cell including a battery, such as a lithium battery, is a carbonaceous material such as graphite. Graphite has excellent capacity maintenance characteristics and potential characteristics, and when alloyed with lithium, the graphite volume does not change. Accordingly, a battery that is manufactured using graphite has high stability. However, graphite has a limitation as a high-capacity battery material, which limitation is recently being reached.

[0003] Also, as the negative active material, a metal that is alloyable (i.e. can be alloyed) with lithium can be used. Examples of a metal that are alloyable with lithium are silicon (Si), tin (Sn), aluminum (Al) etc. Such metals have relatively large electric capacity. However, during charge and discharge, the metals expand in volume and thus some active materials in an electrode may be shorted and the short may result in a substantial decrease in maintenance of capacity in a battery.

[0004] Accordingly, the need is gradually increasing for development of a negative active material and battery with improved performance embodying both high capacity and long-lifetime battery.

[0005] US 2004/234859 A1 discloses a negative active material for a rechargeable lithium battery comprising particles of a metal or a metal compound or mixtures thereof, distributed in a carbonaceous material, the metal or the metal compound being capable of forming an alloy with lithium during electrochemical charging and discharging.

[0006] US 2006/234127 A1 discloses an anode material comprising a metal core layer capable of repetitive lithium intercalation/deintercalation, an amorphous carbon layer coated on the surface of the metal core layer, and a crystalline carbon layer coated on the amorphous carbon layer.

[0007] WO 2004/049473 A2 discloses an electrode material comprising a particle comprising a silicon and/or silicon compound-containing carbonaceous material deposited onto at least a portion of the surfaces of a carbon particle having a graphite structure.

[0008] L. Yuan et al. in Journal of Power Sources, Vol. 146 (1-2), pages 180-185, 2005 disclose a SnO2 carbon-nanocomposite for use as anodes in lithium batteries.

SUMMARY OF THE INVENTION



[0009] The present invention is an electrode active material according to claim 1, an electrode according to claim6, a lithium battery of claim 7 and a method of preparing an electrode active material according to claim 8.

BRIEF DESCRIPTION OF THE DRAWINGS



[0010] These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1A is a schematic view of a portion of an electrode active material according to an embodiment of the present invention;

FIG. 1B is a schematic cross-sectional view of the electrode active material of FIG. 1A;

FIG. 2 is a schematic view of a lithium battery according to an embodiment of the present invention;

FIG. 3 shows a transmission electron microscope (TEM) image of an active material prepared according to Comparative Example 1;

FIGS. 4A and 4B show TEM images of an active material prepared according to Example 3;

FIGS. 5A and 5B show TEM images of an active material prepared according to Example 4;

FIG. 6 shows a TEM image of an active material prepared according to Comparative Example 8;

FIG. 7 shows a TEM image of an active material prepared according to Example 9;

FIG. 8 shows low angle X-ray diffraction test results of active materials prepared according to Comparative Example 1, Example 3, and Comparative Examples 5 to 7;

FIG. 9 shows high angle X-ray diffraction test results of active materials prepared according to Comparative Example 1, Example 3, and Comparative Examples 5 to 7;

FIG. 10 shows X-ray diffraction test results of active materials prepared according to Comparative Example 1 and Examples 1 to 4;

FIG. 11 shows X-ray diffraction test results of active materials prepared according to Comparative Example 8 and Examples 7 to 10;

FIG. 12 shows a pore size distribution graph of active materials prepared according to Comparative Example 1 and Examples 1 to 4;

FIG. 13 shows a pore size distribution graph of active materials prepared according to Comparative Example 8 and Examples 7 to 10;

FIG. 14 shows Raman spectra of active materials prepared according to Comparative Example 2, and Examples 5 and 6;

FIG. 15 shows Raman spectra of active materials prepared according to Example 3 and Comparative Example 6;

FIG. 16 shows thermogravimetric analysis (TGA) results of active materials prepared according to Comparative Example 1 and Examples 1 to 4;

FIG. 17 shows conductivity data of a pore-free SnO2 spherical core and active materials prepared according to Comparative Example 2 and Example 5;

FIG. 18 shows conductivity data of active materials prepared according to Comparative Examples 1 and 5 and Example 3;

FIG. 19 shows a 1st cycle charge and discharge curve and a 50th cycle charge and discharge curve of a lithium battery including a negative electrode including respectively active materials prepared according to Comparative Example 1 and Example 3;

FIG. 20 is a graph of a capacity maintenance rate (%) of a lithium battery including a negative electrode including respectively active materials prepared according to Comparative Example 1 and Examples 1 to 4; and

FIG. 21 is a graph of a capacity maintenance rate (%) of a lithium battery including a negative electrode including respectively active materials prepared according to Comparative Example 8 and Examples 7 to 10.


DETAILED DESCRIPTION OF THE EMBODIMENTS



[0011] Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

[0012] Hereinafter, electrode active materials, electrodes including the electrode active materials, lithium batteries and capacitors including the electrodes, and methods of preparing the electrode active materials according to exemplary embodiments of the present invention will be described in detail.

[0013] An electrode active material according to an embodiment of the present invention includes a porous core including at least a metal oxide comprising at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide, and bismuth oxide that enable intercalation and deintercalation of lithium ions; a crystalline carbon thin film having a thickness of 2 nm or less that is formed on at least a portion of a surface of the porous core, wherein the electrode active material is in the form of a particle comprising pores and a skeleton that forms walls between adjacent pores, wherein at least one of the size of the particle, the average size of the pores and the thickness of the skeleton have a nano-size.

[0014] The expression "electrode active material having a nano-structure" means that at least one of the dimensions of the electrode active material has a nano size (of 100 nm or less, for example, in a range of about 1 nm to about 80 nm, or in a range of about 5 nm to about 50 nm). The electrode active material having a nano-structure is in the form of a particle and includes a pore and a skeleton that forms walls between adjacent pores. The average size of the particle, the average size of pores, and the thickness of the skeleton have the nano-sizes as described above.

[0015] Due to the nano-structure of the electrode active material, lithium ions may be smoothly intercalated into and deintercalated from the electrode active material. Also, the electrode active material may be uniformly dispersed in an electrode including the electrode active material. Accordingly, an electrode including the electrode active material having a nano-structure may have improved electrical characteristics.

[0016] Since the electrode active material includes a pore and a skeleton that forms walls between adjacent pores, the pores have a uniform shape and distribution. Thus, the electrode active material may have an ordered porosity. The pore size and the skeleton thickness have nano sizes as described above.

[0017] The electrode active material includes pores, the electrode active material therefore easily tolerates stress caused by volumetric expansion during charge and discharge. Also, due to the pores, the electrode active material has a very large specific area and thus, the contact area between the electrode active material and the electrolyte may be increased. Herein, if the skeleton thickness is a nano-size (for example, 10 nm or less), the diffusion path of lithium ions in the skeleton may be reduced and thus high-rate characteristics may be improved.

[0018] The electrode active material includes the pores and skeleton as described above. Since the electrode active material includes the pores and the skeleton as described above, because the skeleton of the electrode active material has a network structure, resistance may decrease and thus power loss may decrease. Also, because pores of the electrode active material are orderly arranged, an electrochemical reaction may uniformly occur and thus a local loss or deterioration of the electrode active material may be preventable.

[0019] The porous core included in the electrode active material includes at least a metal oxide that enable intercalation and deintercalation of lithium ions. To dehydrate with a carbon-based precursor of Formula 1, the metal oxide may each include an element having a surface to which a hydroxyl group is bondable. The carbon-based precursor of Formula 1 will be described below.

[0020] The metal oxide includes at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide, and bismuth oxide. The porous core may be an alloy or oxide composite that includes different kinds of metal, and the porous core structure may form a composite with lithium.

[0021] For example, the porous core structure may include at least one of SnO2 and MoO2, but is not limited thereto.

[0022] The crystalline carbon thin film may be formed on at least a portion of the surface of the porous core structure to improve rate characteristics and conductivity of the electrode active material. Also, the crystalline carbon thin film may function as a resistor against a volumetric change of the porous core structure during charge and discharge of the electrode active material to reduce any physical structural change of the electrode active material. Accordingly, lifetime characteristics of a lithium battery including an electrode including the electrode active material may have improved lifetime characteristics.

[0023] The thickness of the crystalline carbon thin film is 2 nm or less, for example, about 0.1 nm to about 2 nm. According to an embodiment of the present invention, the thickness of the crystalline carbon thin film may be 1 nm or less, for example, in a range of about 0.1 nm to about 1 nm, but is not limited thereto.

[0024] At least a portion of the crystalline carbon thin film may include a single- or multi-graphene layer. "Graphene" refers to an allotrope or form of carbon that consists of carbon atoms that are bonded by sp2 bonding to form a two-dimensional atomic planar structure. Accordingly, the thickness of the single graphene layer may be substantially the same as a diameter of a carbon atom. The multi-graphene layer refers to a layer that includes a plurality of graphene layers stacking in a direction perpendicular to the direction in which carbon atoms of one graphene layer extend. The multi-graphene layer may be a layer formed by stacking two to ten, for example, two to five graphene sheets. Accordingly, the thickness of the crystalline carbon thin film may be one to ten times, or one to five times, or one to two times, greater than the diameter of a carbon atom, but is not limited thereto.

[0025] Due to excellent crystallinity, the crystalline carbon thin film may improve conductivity of the electrode active material. For example, regarding a Raman spectrum of the crystalline carbon thin film, the peak intensity ratio of ID/IG may be 0.7 or less, for example, 0.65 or less, wherein ID represents the intensity of peak D that is present at a wave number of 1360±10 cm-1 and IG represents the intensity of peak G that is present at a wave number of 1580±10 cm-1. The peak D shows a disorder or defect of the carbon thin film and the peak G shows an sp2 bond which is a graphite bond of the crystalline carbon thin film. If the value ID/IG of the crystalline carbon thin film satisfies the ranges described above, the crystalline carbon thin film may have excellent crystallinity, and thus, conductivity of the electrode active material may be increased.

[0026] Accordingly, at 31.83 Mpa, the electrode active material may have a conductivity of about 2.0 x 10-5 S/cm to about 1.0 x 10-2 S/cm, for example, about 7.1 x 10-4 S/cm to about 1.0 x 10-3 S/cm. As described above, the electrode active material has such a range of conductivity while maintaining the nano-structure, and thus is useful in a lithium battery. The conductivity may be obtained by, for example, using a carbon-based precursor of Formula 1, which will be described below, as a carbon thin film source.

[0027] When A represents the specific surface area of the porous core structure and B represents the mass of the carbon thin film, B/A may be 7.69 x 10-3 g2/m2 or less (in a case of an active material that includes 10 graphene layers as the carbon thin film and the porous core structure having a specific surface area of 100 m2/g), for example, about 5.0 x 10-4 g2/m2 to about 2.0 x 10-4 g2/m2. The B/A value may be obtainable because the carbon thin film has a micro/nano and uniform thickness of, for example, 1 to 10 times greater than the carbon atom diameter. For reference, theoretically, the specific surface area of one graphene layer is 2600 m2/g and if the graphene layer is completely coated, the B/A value may be 7.69 x 10-4 g2/m2.

[0028] The electrode active material has the nano-structure and the carbon thin film described above. FIG. 1A is a schematic enlarged view of a portion of an electrode active material 10 according to an embodiment of the present invention, wherein the electrode active material 10 includes a pore 16 and a skeleton that forms walls between adjacent pores 16, and FIG. 1B is a schematic sectional view of the electrode active material 10 of FIG. 1A. The electrode active material 10 includes a porous core structure 12 and a carbon thin film 14, and the carbon thin film 14 may be formed on at least a portion of the surface of the porous core structure 12. For example, the carbon thin film 14 may be formed on an exposed surface of the porous core structure 12 and an inner wall of the pore 16.

[0029] The pore 16 of the electrode active material 10 may have a bimodal size distribution. Due to the bimodal size distribution of the pore 16, a stress that may occur due to an expansion rate difference caused by an inner structure difference of the electrode active material (for example, porous core 12) during charge and discharge may be easily tolerated. The bimodal size distribution of the pore 16 may be confirmed by appearance of two pore diameter peaks in a Barrett-Joyner-Halenda (BJH) pore size distribution graph obtained by a nitrogen adsorption test.

[0030] The bimodal size distribution graph of the pore 16 may have a first peak that is present in a range of about 1 nm to about 5 nm and a second peak that is present in a range of about 10 nm to about 20 nm. For example, the pore may have a first peak that is present in a range of about 2 nm to about 5 nm and a second peak that is present in a range of about 16 nm to about 20 nm. That is, the electrode active material 10 may include first ordered nano-pores having a size of less than 10 nm and second ordered nano-pores having a size of more than 10 nm.

[0031] The electrode active material 10 may have an ordered mesoporous structure. The detailed order of the pore 16 of the electrode active material 10 may be confirmed in view of a peak that appear in a low angle X-ray diffraction spectrum.

[0032] In a low angle X-ray diffraction spectrum, a peak of the electrode active material 10 with respect to a (110) plane, may appear at 2θ of 0.6±0.2°.

[0033] For example, the electrode active material 10 may have, in a low angle X-ray diffraction spectrum, a typical meso structure of Tetragonal I41/a (or a sub- structure thereof). This shows that the electrode active material 10 has a highly ordered three-dimensional pore structure and skeleton structure. In particular, a diffraction peak with respect to the (110) plane may be related to a pore corresponding to the second peak in the bimodal size distribution of the pore 16. That is, if a peak corresponding to the second peak is present in the bimodal size distribution of the pore 16, a peak corresponding to the (110) plane is also present in the low angle X-ray diffraction spectrum.

[0034] The thickness (D) of the skeleton that forms walls between adjacent pores 16 of the electrode active material 10 may be about 5 nm or more. For example, the thickness (D) of the skeleton may be in a range of about 5 nm to about 20 nm. For example, the thickness (D) of the skeleton may be in a range of about 5 nm to about 10 nm. For example, the thickness (D) of the skeleton may be in a range of about 10 nm to about 20 nm. For example, the thickness (D) of the skeleton may be in a range of about 10 nm to about 15 nm. If the thickness of the skeleton (D) is within the ranges described above, crystallization of the porous core 12 may effectively occur.

[0035] The crystal size of the porous core 12 of the electrode active material 10 may be 5 nm or more. For example, the crystal size of the porous core 12 of the electrode active material 10 may be in a range of about 5 nm to about 30 nm.

[0036] The specific surface area of the electrode active material 10 may be in a range of about 50 m2/g to about 250 m2/g. For example, the specific surface area of the electrode active material 10 may be in a range of about 100 m2/g to about 150 m2/g. Due to having such ranges of the specific surface area, the electrode active material 10 may contribute to electrical performance improvement of a lithium battery, a capacitor, or the like. The specific surface area may be adjusted by controlling the size of the pore 16 or the size (or thickness) of the skeleton (D). When the electrode active material 10 has such specific surface area ranges, a flow or diffusion path of lithium ions with respect to the electrode active material 10 may be easily obtained, and stability of the electrode active material 10 may be secured.

[0037] The volume of the pore 16 of the electrode active material 10 may be in a range of about 0.1 cm3/g to about 2 cm3/g. For example, the volume of the pore 16 of the electrode active material 10 may be in a range of about 0.5 cm3/g to about 1 cm3/g. When the volume of the pore 16 is within the ranges described above, the electrode active material 10 may contribute to an electrical performance improvement of a lithium battery, a capacitor, or the like. The pore volume may be adjusted by controlling the size of the pore 16 or the size (or thickness) of the skeleton (D). When the volume of the pore 16 is within the ranges described above, a flow or diffusion path of lithium ions with respect to the electrode active material 10 may be easily obtained, and stability of the electrode active material 10 may be secured.

[0038] The pores 16 of the electrode active material 10 may be connected to each other to form a channel. Due to the formation of the channel, an electrolyte may easily permeate into the electrode active material 10 and lithium ions may easily move.

[0039] The term "the surface of the porous core" in "crystalline carbon thin film formed on at least a portion of the surface of the porous core" may include, when the porous core includes pores and a skeleton that forms walls between adjacent pores, an inner wall of the pore.

[0040] The porosity of the electrode active material 10 may be 80 % or less. For example, the porosity of the electrode active material 10 may be in a range of about 10 % to about 70 %. The porosity refers to a ratio of a volume of the pore 16 to the whole volume of the electrode active material 10. When the porosity is within the ranges described above, the electrode active material 10 may have excellent lifetime characteristics and energy density.

[0041] The electrode active material may be included in an electrode, for example, an electrode for a lithium battery. Accordingly, an electrode including the electrode active material may be provided. The electrode may be a positive or negative electrode for a lithium battery. For example, the electrode may be a negative electrode for a lithium battery.

[0042] A method of manufacturing the negative electrode for a lithium battery will now be described in detail. The electrode active material, a conducting agent, a binder, and a solvent may be mixed to prepare a negative active material composition, and the prepared negative active material composition may be directly coated on a copper current collector to manufacture a negative electrode plate. Alternatively, the prepared negative active material composition may be cast onto a separate support and a negative active material film separated from the separate support may be laminated on a copper current collector to a negative electrode plate.

[0043] Examples of the conducting agent may be carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, carbon fiber; carbon nanotube; metal powder or metal fiber or metal tube of copper, nickel, aluminum, silver, or the like; and a conductive polymer such as a polyphenylene derivative. However, the conducting agent is not limited thereto, and may be any one of various materials that are used as a conducting agent in the art.

[0044] Examples of the binder are a vinylidene fluoride/hexafluoropropylene copolymer, polyvinylidenefluoride, polyacrylonitrile, polymethylmethacrylate, polytetrafluoroethylene (PTFE), a mixture of the forgoing polymers, and a styrene butadiene rubber-based polymer. Examples of the solvent are N-methylpyrrolidone (NMP), acetone, and water. The binder and the solvent are not limited to these materials and may be any of various materials that are used in the art.

[0045] According to an embodiment, the negative active material composition may further include a plasticizer to form pores in an electrode plate.

[0046] Amounts of the negative active material, the conducting agent, the binder, and the solvent may be at the same levels as conventionally used in a lithium battery. According to the purpose and structure of a lithium battery, one or more of the conducting agent, the binder, and the solvent may be omitted.

[0047] Also, the negative active material may further include, in addition to the electrode active material, a conventional negative active material. The conventional negative active material may be any one of various materials that are used as a negative active material for a lithium battery in the art. For example, the conventional negative active material may include at least one material selected from the group consisting of lithium metal, a metal that is alloyable with lithium, a transition metal oxide, a non-transition metal oxide, and a carbonaceous material.

[0048] For example, the metal that is alloyable with lithium may be Si, Sn, Al, Ge, Pb, Bi, Sb, an Si-X alloy where X is an alkali metal, an alkali earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof and is not silicon (Si), Sn-T alloy where T is an alkali metal, an alkali earth metal, a rare earth element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof and is not tin (Sn), or the like. The elements X or T may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0049] For example, the transition metal oxide may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, or the like.

[0050] For example, the non-transition metal oxide may be SnO2, SiOx(0<x<2), or the like.

[0051] The carbonaceous material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be a natural or artificial graphite of a shapeless, plate, flake, sphere, or fiber type. The amorphous carbon may be soft carbon (low-temperature calcined carbon), hard carbon, a mesophase pitch carbide, calcined coke, or the like.

[0052] Also, the negative electrode may be used, in addition to a lithium battery, in other electrochemical cells, such as a super capacitor. In this case, the manufacturing method, the electrode composition, the electrode structure, or the like may be appropriately modified except for the use of the negative active material described above.

[0053] For example, an electrode for a capacitor may be manufactured by coating the negative active material on a metal structure that has been disposed on a conductive substrate. Alternatively, the negative active material may be directly coated on a conductive substrate to manufacture an electrode for a capacitor.

[0054] Like the negative electrode, a positive electrode including the electrode active material may also be manufactured by using any of various materials that are conventionally used in a positive electrode for a lithium battery and a method that is similar to the method described above.

[0055] A lithium battery according to an embodiment of the present invention includes a positive or negative electrode that includes the electrode active material. For example, the lithium battery may include a negative electrode including the electrode active material. An example of a method of manufacturing the lithium battery will now be described in detail.

[0056] First, a negative electrode including the electrode active material may be manufactured as described above according to an embodiment of the present invention.

[0057] Then, a positive electrode may be manufactured as follows. The positive electrode may be manufactured in the same manner as used to manufacture the negative electrode, except that a positive active material is used instead of the negative active material.

[0058] A positive active material composition may include the conducting agent, the binder, and the solvent which have been used in preparing the negative electrode. A positive active material, a conducting agent, a binder, and a solvent may be mixed to prepare a positive active material composition. The positive active material composition may be coated directly on an aluminum current collector and dried to manufacture a positive electrode plate including a positive active material layer. Alternatively, the positive active material composition may be cast onto a separate support and a film separated from the separate support may be laminated on an aluminum current collector to manufacture a positive electrode plate including a positive active material layer.

[0059] The positive active material may be any one of various lithium-containing metal oxides that are conventionally used in the art. For example, the positive active material may include at least one composite oxide of lithium and metal selected from the group consisting of cobalt, manganese, nickel, and a combination thereof. A detailed example of the positive active material may be a compound represented by any one of various formulae including LiaA1-bLbD2 where 0.90 ≤ a ≤ 1.8 and 0 ≤ b ≤ 0.5; LiaE1-bLbO2-cDc where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05; LiE2-bLbO4-cDc where 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05; LiaN1-b-cCobLcDα where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α ≤ 2; LiaNi1-b-cCobLcO2-αFα where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2; LiaNi1-b-cCobLcO2-αR2 where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2; LiaNi1-b-cMnbLcDα where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α ≤ 2; LiaNi1-b-cMnbLcO2-αRα where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2; LiaNi1-b-cMnbLcO2-αR2 where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2; LiaNibEcGdO2 where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; LiaNibCOcMndGeO2 where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, and 0.001 ≤ e ≤ 0.1; LiaNiGbO2 where 0.90 ≤ a ≤ 1.8, and 0.001 ≤ b ≤ 0.1; LiaCoGbO2 where 0.90 ≤ a ≤ 1.8, and 0.001 ≤ b ≤ 0.1; LiaMnGbO2 where 0.90 ≤ a ≤ 1.8, and 0.001 ≤ b ≤ 0.1; LiaMn2GbO4 where 0.90 ≤ a ≤ 1.8, and 0.001 ≤ b ≤ 0.1; QO2; QS2; LiQS2; V2O5; LiV2O5; LiZO2; LiNiVO4; Li(3-f)J2(PO4)3(0 ≤ f ≤ 2); Li(3-f)Fe2(PO4)3(0 ≤ f ≤ 2); and LiFePO4.

[0060] In these formulae, A is Ni, Co, Mn, or a combination thereof; L is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; R is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; Z is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0061] For example, LiCoO2, LiMnxO2x(x=1, 2), LiNi1-xMnxO2x(0<x<1), Ni1-x-yCoxMnyO2 (0≤x≤0.5, 0≤y≤0.5), LiFePO4, or the like may be used.

[0062] A coating layer may be further formed on these compounds, or a mixture of these compounds and a compound having a coating layer is also used. The coating layer may be an oxide of a coating element, a hydroxide of a coating element, an oxyhydroxide of a coating element, an oxycarbonate of a coating element, or a hydroxycarbonate of a coating element. The compound that forms the coating layer may be amorphous or crystalline. The coating element contained in the coating layer may be Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The coating layer formation process may be any one of various coating methods (for example, spray coating or precipitating) that do not adversely affect properties of the positive active material when these elements are used with respect to the compounds. The coating layer formation process may be obvious to one of ordinary skill in the art and thus will not be described herein in detail.

[0063] Amounts of the positive active material, the conducting agent, the binder, and the solvent may be at the same levels as conventionally used in a lithium battery. Then, a separator that is to be interposed between the positive electrode and the negative electrode may be prepared. The separator may be any separator that is conventionally used in a lithium battery. For example, the separator may be a material that has a low resistance to migration of ions of an electrolyte and an excellent electrolyte -retaining capability. For example, the separator may include a material selected from the group consisting of glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and a combination thereof, each of which may be nonwoven or woven. For example, a separator for use in a lithium ion battery may be a foldable separator formed of polyethylene or polypropylene, and a separator for use in a lithium ion polymer battery may be a separator having an excellent organic electrolyte retaining capability. An example of a method of manufacturing the separator will now be described in detail.

[0064] A separator composition may be prepared by mixing a polymer resin, a filler, and a solvent. The separator composition may be directly coated and dried on an electrode, thereby forming a separator. Alternatively, the separator composition may be cast and dried on a support as a film and then the separator film separated from the support may be laminated on an electrode, thereby forming a separator.

[0065] A polymer resin that is used to produce the separator may be any material that is used in a binder of an electrode plate. For example, the polymer resin may be a vinylidenefluoride/hexafluoropropylene copolymer, polyvinylidenefluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, or a combination thereof.

[0066] Next, an electrolyte may be prepared. For example, the electrolyte may be an organic electrolyte. Also, the electrolyte may be solid. For example, the solid electrolyte may be boron oxide, lithium oxynitride, or the like, but is not limited thereto. For example, the solid electrolyte may be any one of various solid electrolytes that are used in the art. The solid electrolyte may be formed on the negative electrode by, for example, sputtering.

[0067] For example, an organic electrolyte may be prepared. The organic electrolyte may be prepared by dissolving a lithium salt in an organic solvent. The organic solvent may be any one of various organic solvents that are used in the art. For example, the organic solvent may be propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate (methylethyl carbonate), methyl n-propyl carbonate, ethyl n-propyl carbonate, methylisopropyl carbonate, di-n-propyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, , sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethyleneglycol, dimethylether, or a mixture thereof.

[0068] The lithium salt may be any one of various lithium salts that are used in the art. For example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2)(x and y are natural numbers), LiCI, Lil, or a mixture thereof may be used.

[0069] Referring to FIG. 2, a lithium battery 1 includes a positive electrode 3, a negative electrode 2, and a separator 4. The positive electrode 3, the negative electrode 2, and the separator 4 are wound or folded to be housed in a battery case 5. Subsequently, an electrolyte is loaded into the battery case 5 and then sealed with a cap assembly 6, thereby completing manufacture of the lithium battery 1. The battery case 5 may be cylindrical, rectangular, thin film-shaped, or the like. For example, the lithium battery 1 may be a large thin film-type battery. Alternatively, the lithium battery 1 may be a lithium ion battery.

[0070] The separator is disposed between the positive electrode plate and the negative electrode plate to form a battery assembly. A plurality of the battery assemblies are stacked in a bi-cell structure, and then impregnated with an electrolyte, and the obtained structure is housed in a pouch, followed by sealing, thereby completing manufacture of a lithium ion polymer battery.

[0071] Also, a plurality of the battery assemblies are stacked on each other to form a battery pack, and the battery pack may be used in various devices that require high capacity and high power output. For example, the battery pack may be used in a notebook computer, a smart phone, an electric vehicle, or the like.

[0072] Also, the lithium battery may be used in an electric vehicle (EV) due to its storage stability at high temperature, excellent lifetime characteristics, and high-rate characteristics. For example, the lithium battery may be used in hybrid vehicles, such as a plug-in hybrid electric vehicle (PHEV).

[0073] A capacitor according to an embodiment of the present invention includes a negative electrode including the electrode active material. For example, the capacitor may be a super capacitor having a very high power accumulation capacity.

[0074] The capacitor may employ the negative electrode including the electrode active material. The capacitor may be manufactured by disposing a separator between a positive electrode and a negative electrode, followed by injection of an electrolyte into the separator. The positive electrode herein may be any one of various electrodes that are used in the art.

[0075] The electrolyte may include a solvent and, as the solvent, at least one solvent selected from the group consisting of acetonitrile, dimethyl ketone, and propylene carbonate may be used. The electrolyte may include an alkali metal salt that has a solubility of 0.01 mole/L or more with respect to the solvent and that is electrically inactive in a working voltage range of the capacitor. Examples of the alkali metal salt are lithium perchlorate, lithium tetrafluoroborate, lithium hexafluorophosphate, etc. The electrolyte may further include additives for improving properties of the capacitor. For example, a stabilizer or a thickener may be used.

[0076] Also, the lithium battery and/or capacitor may include the electrode active material as a positive active material.

[0077] A method of preparing the electrode active material according to an embodiment of the present invention includes forming a carbon-based moiety represented by Formula 2 below on at least a portion of a surface of a porous core including at least a metal oxide comprising at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide, and bismuth oxide that enable intercalation and deintercalation of lithium ions by mixing i) the porous core, ii) a carbon-based precursor represented by Formula 1 below, and iii) a solvent to form a self-assembled monolayer of the compound according to Formula 2 on said surface; and converting the self-assembled monolayer into a crystalline carbon thin film by heating the porous core on which the self-assembled monolayer is formed in an inert atmosphere.

wherein in Formulae 1 and 2,

ring A is a substituted or unsubstituted C5-C30 aromatic ring or a substituted or unsubstituted C2-C30 heteroaromatic ring,

a and b are each independently an integer of 1 to 5, and

* denotes a binding site with the surface of the porous core.



[0078] The detailed description about the porous core included in the mixture has been already presented above. The porous core may include a nano-structure as described above. For example, if the porous core having a nano-structure is in the form of a particle, the average particle size of the porous core having the nano-structure may be a nano-size as described above. Also, if the porous core having the nano-structure is in the form of a particle and has a pore and a skeleton that forms walls between adjacent pores, the average particle size of the porous core, average particle size of the pore, and thickness of the skeleton may be nano-sizes as described above.

[0079] A method of manufacturing the porous core having pores according to an embodiment of the present invention may include impregnating silica (SiO2), Al2O3, ZnO, MgO, carbon, or the like, which are used as a porous template, with a liquid including a precursor of the porous core; heating the porous template impregnated with the liquid including the porous core precursor to form a porous template-core composite; and removing the porous template from the porous template-core composite.

[0080] The porous template may have a nano-structure that is related to a target nano-structure of the porous core.

[0081] The porous core precursor may be a nitride, a chloride, a sulfide, a salt (for example, ammonium salt), a cyanide, an oxide, or an alkoxide, which are materials including the metal or oxide of the metal included in the porous core. For example, if the porous core includes SnO2, the porous core precursor may be a salt including tin (for example, Sn(NO3)2·6H2O, Sn(CH3COO)2·xH2O, etc.) and a chloride including tin (for example, SnCl2·xH2O, (wherein, x is an integer number and for example, SnCl2· 2H2O (Tin(II) chloride dihydrate)) etc.), but is not limited thereto. Alternatively, if the porous core includes MoO2, the porous core precursor may be a salt including molybdenum (for example, (NH4)6Mo7O24· 4H2O (Ammonium molybdate tetrahydrate)), but is not limited thereto.

[0082] The liquid including the porous core precursor may either be a melted product (for example, SnCl2· 2H2O is used as a melted product) that is obtained by heating the porous core precursor or a solution that is obtained by dissolving the porous core precursor in a solvent, such as water, alcohol, or the like (for example, (NH4)6Mo7O24· 4H2O is used by dissolving in water).

[0083] The heating temperature may be in a range of about 300°C to about 700°C. For example, the heating temperature may be in a range of about 500°C to about 550°C. If the heating temperature is within the ranges described above, crystallinity of the porous core in the porous template-core composite as the heated product may increase. The heating may be performed in an oxidizing atmosphere or a reducing atmosphere. The reducing atmosphere may be an atmosphere including at least one gas selected from the group consisting of nitrogen gas, argon gas, helium gas, and hydrogen gas. The oxidizing atmosphere may be an atmosphere including oxygen. For example, the oxidizing atmosphere may include air.

[0084] The removing of the porous template from the porous template-core composite may be performed by contacting the porous template-core composite with an etchant. For example, the etchant may be selected from the group consisting of a fluoric acid (HF), NaOH, and HF-NH4F (buffer), but is not limited thereto. The etchant may be an acid or a base.

[0085] The carbon-based precursor may include, as represented by Formula 1, an aromatic ring or heteroaromatic ring having a conjugation structure and one to five hydroxyl groups.

[0086] In Formula 1, the ring A may be a substituted or unsubstituted benzene, a substituted or unsubstituted pentalene, a substituted or unsubstituted indene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted azulene, a substituted or unsubstituted heptalene, a substituted or unsubstituted indacene, a substituted or unsubstituted acenaphthylene, a substituted or unsubstituted fluorene, a substituted or unsubstituted phenalene, a substituted or unsubstituted phenanthrene, a substituted or unsubstituted anthracene, a substituted or unsubstituted fluoranthene, a substituted or unsubstituted triphenylene, a substituted or unsubstituted pyrene, a substituted or unsubstituted chrysene, a substituted or unsubstituted naphthacene, a substituted or unsubstituted picene, a substituted or unsubstituted perylene, a substituted or unsubstituted pentaphene, a substituted or unsubstituted hexacene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted imidazole, a substituted or unsubstituted imidazopyridine, a substituted or unsubstituted imidazopyrimidine, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted indole, a substituted or unsubstituted purine, a substituted or unsubstituted quinoline, a substituted or unsubstituted phthalazine, a substituted or unsubstituted indole, a substituted or unsubstituted naphthyridine, a substituted or unsubstituted quinazoline, a substituted or unsubstituted cinnoline, a substituted or unsubstituted indazole, a substituted or unsubstituted carbazole, a substituted or unsubstituted phenazine, a substituted or unsubstituted phenanthridine, a substituted or unsubstituted triazine, a substituted or unsubstituted phenanthroline, or a substituted or unsubstituted quinoxaline, but is not limited thereto.

[0087] If the ring A is a substituted C5-C30 aromatic ring or a substituted or unsubstituted C2-C30 heteroaromatic ring, the substituent may be a halogen atom, a cyano group, a carboxylic group or a salt thereof, a C1-C10 alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, or the like), or a C1-C10 alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or the like), but is not limited thereto.

[0088] For example, the ring A may be a substituted or unsubstituted C5-C30 aromatic ring or a substituted or unsubstituted C2-C30 heteroaromatic ring, which is fused with only an unsubstituted 6-membered ring.

[0089] According to an embodiment of the present invention, in Formula 1, the ring A is benzene, naphthalene, phenalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphene, hexacene, pyridine, pyrazine, pyrimidine, pyridazine, quinoline, phthalazine, quinoxaline, quinazoline, cinnoline, phenanthridine, phenanthroline, or phenazine, and a and b may each be 1 or 2, but is not limited thereto.

[0090] The solvent may be selected from typical solvents that do not chemically react with the porous core and carbon-based precursor, are removable at a relatively low temperature, and function as a medium that allows the porous core to effectively contact with the carbon-based precursor. The solvent may be acetone, ethanol, distilled water, or the like, but is not limited thereto.

[0091] As a result of contacting the porous core and the carbon-based precursor, the carbon-based moiety represented by Formula 2 may be bonded to the surface of the porous core. The carbon-based moiety may be formed by dehydration between a hydroxyl group that is present at the surface of the porous core and a hydroxyl group of the carbon-based precursor.

[0092] The bonding of the carbon-based moiety on the surface of the porous core may be performed by preparing the mixture described above. Alternatively, the bonding may be performed by heating that is performed to promote the dehydration between a hydroxyl group that is present at the surface of the porous core and a hydroxyl group of the carbon-based precursor. Heating conditions for promoting the dehydration may vary according to compositions and amounts of the porous core and the carbon-based precursor. For example, the heating may be performed in an inert atmosphere (for example, an atmosphere including at least one of nitrogen gas, argon gas, helium gas, and hydrogen gas) at a temperature of about 100°C to about 500°C, and for 1 hour to 5 hours.

[0093] Subsequently, the porous core that has a surface to which the carbon-based moiety is bonded may be heated in a gaseous atmosphere (for example, an atmosphere including at least one of nitrogen gas, hydrogen gas, or inert gases such as argon gas or helium gas) to carbonate the carbon-based moiety of FIG. 2 bonded to the surface of the porous core, thereby converting the carbon-based moiety into a crystalline carbon thin film as described above. Thus, the preparation of the electrode active material including the porous core and the crystalline carbon thin film formed on at least a portion of the surface of the porous core may be completed.

[0094] Heating conditions for the porous core having a surface to which the carbon-based moiety is bonded may vary according to compositions and amounts of the porous core and the carbon-based precursor. For example, heating may be performed at a temperature of about 300°C to about 600°C (for example, about 400°C to about 500°C) for 1 hour to 5 hours (for example, 1 hour to 3 hours).

[0095] Because the carbon-based moiety on the surface of the porous core is bonded to the surface of the porous core while oxygen is interposed therebetween as confirmed by Formula 2, a self-assembled mono layer (SEM layer) that includes the carbon-based moiety of Formula 2 may be formed on the surface of the porous core. The SEM layer including the carbon-based moiety of Formula 2 is converted into a crystalline carbon thin film by heating and the crystalline carbon thin film of the electrode active material may be very thin (for example, 2 nm or less) or may have a uniform thickness. Accordingly, as illustrated in FIG. 1B, a crystalline carbon thin film 14 having a uniform thickness may be formed on an inner wall of a pore 16 that has a nano-size.

[0096] Also, because the crystalline carbon thin film is formed by heating the ring A of the carbon-based moiety of Formula 2 and the ring A is an aromatic or heteroaromatic ring having a conjugated structure, the crystalline carbon thin film may have excellent crystallinity. The electrode active material including the crystalline carbon thin film formed from the carbon-based precursor of Formula 1 may have excellent conductivity.

[0097] Also, because the ring A of the carbon-based moiety of Formula 2 is an aromatic or heteroaromatic ring having a conjugated structure, the heating temperature for the conversion into the crystalline carbon thin film is relatively low. Typically, the higher the temperature at which a carbon-based compound is converted into a carbon thin film, the higher crystallinity a formed carbon thin film may have. However, when an active material is exposed at high temperature, the crystal structure of the active material changes and the nano-structure of the active material may collapse (for example, pore collapse). For example, as confirmed in X-ray diffraction patterns (B and C of FIGS. 8 and 9) of active materials prepared according to Comparative Examples 6 and 7 (see below), once exposed to high temperature, pores included in the active material may collapse and the crystal structure of the active material may change. However, because the carbon-based precursor of Formula 1 has the ring A having a conjugated structure and at least one hydroxyl group that is bondable to the surface of the porous core, conversion into the carbon thin film having excellent crystallinity may be easily obtained at low temperature at which the nano-structure and crystal structure of the porous core do not change. By doing so, the electrode active material that maintains a nano-structure and has high conductivity may be obtained.

[0098] One or more embodiments will now be described in further detail with reference to the following examples. These examples are for illustrative purpose only and are not intended to limit the scope of the one or more embodiments. In the following examples, Examples 5 and 6 do not fall within the scope of claim 1 and are provided for references purposes only.

[Example]


(Preparation of Active Material)



[0099] In the following examples the materials of Examples 4 and 5 do not fall within the scope of the claims and are provided for reference purposes only.

Example 1



[0100] SnCl2·2H2O was melted by heating to prepare a SnCl2·2H2O melted product, and the SnCl2·2H2O melted product was loaded into a porous SiO2 (KIT-6, powder in which three-dimensional pores were connected to each other). In this case, the SnCl2·2H2O melted product was loaded into the porous SiO2 in such a way that the amount of SnO2 was 40 parts by weight based on 100 parts by weight of SiO2. Subsequently, the porous SiO2 into which SnCl2·2H2O was loaded was heated under an atmospheric condition at a temperature of 550°C for 3 hours, thereby producing a SiO2-SnO2 composite. The composite was added to a 10 wt% HF aqueous solution and reacted for 10 minutes, and this adding and reacting process was performed again to remove the SiO2 template, followed by filtering. As a result, a SnO2 porous core having a skeleton having a thickness of about 7 nm as illustrated in FIG. 3 was obtained.

[0101] One g of the SnO2 porous core, 0.02 g of 2,3-dihydroxynaphthalene (DN) as a carbon-based precursor, and 0.5 g of acetone as a solvent were mixed and stirred, and then the resultant mixture (the weight ratio of SnO2 porous core to carbon-based precursor was 1:0.02) was first-heat treated in an N2 atmosphere at a temperature of 200 °C for 2 hours to promote dehydration between the porous core and DN. Then, the temperature was increased to 500°C and a second-heating was performed thereon at a temperature of 500°C for 2 hours, thereby forming an active material in which a carbon thin film was formed on at least a portion of the surface of the SnO2 porous core.

Example 2



[0102] An active material was prepared in the same manner as in Example 1, except that 0.04 g of the carbon-based precursor was used to adjust the weight ratio of the SnO2 porous core to the carbon-based precursor to be 1:0.04.

Example 3



[0103] An active material was prepared in the same manner as in Example 1, except that 0.06 g of the carbon-based precursor was used to adjust the weight ratio of the SnO2 porous core to the carbon-based precursor to be 1:0.06.

Example 4



[0104] An active material was prepared in the same manner as in Example 1, except that 0.08 g of the carbon-based precursor was used to adjust the weight ratio of the SnO2 porous core to the carbon-based precursor to be 1:0.08.

Example 5



[0105] An active material was prepared in the same manner as in Example 3, except that instead of the SnO2 porous core, a pore-free SnO2 core being a spherical particle (product of Aldrich Co., Ltd., SnO2 particles having an average particle size of about 100 nm or less) was used.

Example 6



[0106] An active material was prepared in the same manner as in Example 4, except that instead of the SnO2 porous core, a pore-free SnO2 core being a spherical particle (product of Aldrich Co., Ltd., SnO2 particles having an average particle size of about 100 nm or less) was used.

Example 7



[0107] An active material was prepared in the same manner as in Example 1, except that a MoO2 porous core that was prepared by using a (NH4)6Mo7O24· 4H2O dissolved product in water instead of the SnCl2·2H2O melted product, was used instead of the SnO2 porous core.

Example 8



[0108] An active material was prepared in the same manner as in Example 2, except that a MoO2 porous core that was prepared by using a (NH4)6Mo7O24· 4H2O dissolved product in water instead of the SnCl2·2H2O melted product, was used instead of the SnO2 porous core.

Example 9



[0109] An active material was prepared in the same manner as in Example 3, except that a MoO2 porous core that was prepared by using a (NH4)6Mo7O24· 4H2O dissolved product in water instead of the melted product, was used instead of the SnO2 porous core.

Example 10



[0110] An active material was prepared in the same manner as in Example 4, except that a MoO2 porous core that was prepared by using a (NH4)6Mo7O24· 4H2O dissolved product in water instead of the SnCl2·2H2O melted product, was used instead of the SnO2 porous core.

Comparative Example 1



[0111] An active material including the SnO2 porous core was prepared in the same manner as in Example 1, except that the carbon thin film forming process was not performed.

Comparative Example 2



[0112] An active material was prepared in the same manner as in Example 5, except that sucrose was used instead of2,3-dihydroxynaphthalene.

Comparative Example 3



[0113] An active material was prepared in the same manner as in Example 5, except that sucrose was used instead of 2,3-dihydroxynaphthalene and the second heating temperature was 700 °C.

Comparative Example 4



[0114] An active material powder was prepared in the same manner as in Example 5, except that sucrose was used instead of 2,3-dihydroxynaphthalene and the second heating temperature was 900°C.

Comparative Example 5



[0115] An active material was prepared in the same manner as in Example 3, except that sucrose was used instead of2,3-dihydroxynaphthalene.

Comparative Example 6



[0116] An active material was prepared in the same manner as in Example 3, except that sucrose was used instead of 2,3-dihydroxynaphthalene and the second heating temperature was 700°C.

Comparative Example 7



[0117] An active material was prepared in the same manner as in Example 3, except that sucrose was used instead of 2,3-dihydroxynaphthalene and the second heating temperature was 900°C.

Comparative Example 8



[0118] An active material including the MoO2 porous core was prepared in the same manner as in Example 7, except that the carbon thin film forming process was not performed.

[0119] The active materials prepared according to Examples 1 to 10 and Comparative Examples 1 to 8 are shown in Table 1 below:
[Table 1]
 Core componentCore structureCarbon-based thin film forming precursorCore: precursor weight ratioSecond heating temperature (°C)
Example 1 SnO2 porous DN 1:0.02 500
Example 2 SnO2 porous DN 1:0.04 500
Example 3 SnO2 porous DN 1:0.06 500
Example 4 SnO2 porous DN 1:0.08 500
Example 5 SnO2 bulk (no pore) DN 1:0.06 500
Example 6 SnO2 bulk (no pore) DN 1:0.08 500
Example 7 MoO2 porous DN 1:0.02 500
Example 8 MoO2 porous DN 1:0.04 500
Example 9 MoO2 porous DN 1:0.06 500
Example 10 MoO2 porous DN 1:0.08 500
Comparative Example 1 SnO2 porous - - -
Comparative Example 2 SnO2 bulk (no pore) sucrose 1:0.06 500
Comparative Example 3 SnO2 bulk (no pore) sucrose 1:0.06 700
Comparative Example 4 SnO2 bulk (no pore) sucrose 1:0.06 900
Comparative Example 5 SnO2 porous sucrose 1:0.06 500
Comparative Example 6 SnO2 porous sucrose 1:0.06 700
Comparative Example 7 SnO2 porous sucrose 1:0.06 900
Comparative Example 8 MoO2 porous - - -

Evaluation Example 1: Active Material Observation



[0120] The active materials of Comparative Example 1, Example 3, Example 4, Comparative Example 8, and Example 9 were analyzed by using a high-resolution transmission electron microscopy (HR-TEM), and results thereof are shown in FIG. 3 (active material of Comparative Example 1), FIGS. 4A and 4B (active material of Example 3), FIGS. 5A and 5B (active material of Example 4), FIG. 6 (active material of Comparative Example 8), and FIG. 7 (active material of Example 9), respectively.

[0121] Referring to FIGS. 3 to 7, it was confirmed that the active material powders had porous structures.

[0122] Referring to FIGS. 4B, 5B, and 7, it was confirmed that the active materials of Examples 3, 4, and 9 include nano-size pores that were orderly arranged to be connected to each other to form a channel. The thickness of the nano-skeleton that forms walls between adjacent pores is shown in Table 2 below:
[Table 2]
 Thickness of skeleton that forms walls between adjacent pores [nm]
Example 3 7 ± 1
Example 4 7 ± 1
Example 9 7 ± 1

Evaluation Example 2: X-ray diffraction test



[0123] An X-ray diffraction test was performed using CuKα on the active materials of Comparative Example 1, Example 3, and Comparative Examples 5 to 7, and low angle diffraction patterns and high angle diffraction patterns of the active materials are shown in FIGS. 8 and 9.

[0124] Referring to (a) of FIG. 8, peaks of the active materials of Comparative Example 1 (porous core / carbon thin film not formed), Example 3 in which heating was performed at a temperature of 500°C (porous core / carbon thin film formed using DN), and Comparative Example 5 in which heating was performed at a temperature of 500 °C (porous core / carbon thin film formed using sucrose), all with respect to a (110) plane are present at a Bragg 2θ of 0.6 ±0.2°, and peaks thereof with respect to a (221) plane are present at a Bragg 2θ of 1.0 ±0.2°. The (110) plane and the (221) plane correspond to surfaces of a highly ordered three-dimensional skeleton and pore structure in the porous SnO2. The low angle X-ray diffraction spectrum is a diffraction pattern formed by the ordered arrangement of the nano-sized skeleton and pore structure. Referring to (a) of FIG. 8, it was confirmed that the active materials of Comparative Example 1 (porous core / carbon thin film not formed), Example 3 in which heating was performed at a temperature of 500°C (porous core / carbon thin film formed using DN), and Comparative Example 5, which heating was performed at a temperature of 500°C (porous core / carbon thin film formed using sucrose) have mesoporous structures having ordered nano-size pores.

[0125] However, referring to (b) and (c) of FIG. 8, the peaks of the active materials of Comparative Example 6 in which heating was performed at a temperature of 700°C (porous core / carbon thin film formed using sucrose) and Comparative Example 7 in which heating was performed at a temperature of 900°C (porous core / carbon thin film formed using sucrose) with respect to the (110) plane and the (221) plane were not clear. From this result, it was confirmed that the active materials of Comparative Example 6 and Comparative Example 7 did not have the ordered mesoporous structure any more due to the collapse of a majority of the nano-structure of the SnO2 porous core that had been present before the carbon thin film was formed using sucrose. The collapse of the nano-structure may be due to the high-temperature heating (700°C and 900°C) that is required to form the carbon thin film using sucrose.

[0126] Referring to (a) of FIG. 9, the active materials of Example 3 in which heating was performed at a temperature of 500°C (porous core strucutre / carbon thin film formed using DN) and Comparative Example 5 in which heating was performed at a temperature of 500°C (porous core / carbon thin film formed using sucrose) have peaks at the same Bragg 2θ as that of the active material of Comparative Example 1 (porous core / a carbon thin film was not formed). From this result, it is confirmed that the active materials of Example 3 in which heating was performed at a temperature of 500°C

[0127] (porous core / carbon thin film formed using DN) and Comparative Example 5 (porous core / carbon thin film formed using sucrose) may have the same crystal phase as that of the active material of Comparative Example 1 (porous core / carbon thin film not formed).

[0128] However, referring to (b) and (c) of FIG. 9, the active materials of Comparative Example 6 in which heating was performed at a temperature of 700°C (porous core / carbon thin film formed using sucrose) and Comparative Example 7 in which heating was performed at a temperature of 900°C (porous core / carbon thin film formed using sucrose) have peaks that are not present in (a) of FIG. 9 (see arrows of (b) and (c) of FIG. 9). From this result, it is confirmed that due to the high-temperature heating (700°C and 900°C) for forming a carbon thin film using sucrose, the crystal phase of the SnO2 porous core of the active material of Comparative Example 6 and 7 was changed.

[0129] FIG. 10 shows X-ray diffraction test results of the active materials of Comparative Example 1 and Examples 1 to 4. Referring to FIG. 10, the active materials of Examples 1 to 4 in which the carbon-based precursor was used in different amounts have the same X-ray diffraction pattern as the active material of Comparative Example 1. Accordingly, it was confirmed that the active materials of Examples 1 to 4 maintained their nano-porous structures even after the carbon thin film was formed.

[0130] FIG. 11 shows X-ray diffraction test results of the active materials of Comparative Example 8 and Examples 7 to 10. Referring to FIG. 11, the active materials of Examples 7 to 10 in which the carbon-based precursor was used in different amounts, have the same X-ray diffraction pattern as the active material of Comparative Example 8. Accordingly, it was confirmed that the active materials of Examples 7 to 10 maintained their nano-porous structures even after the carbon thin film was formed.

Evaluation Example 3: Nitrogen Adsorption Test



[0131] A nitrogen adsorption test was performed on the active materials of Comparative Example 1, Examples 1 to 4, Comparative Example 8, and Examples 7 to 10.

[0132] In the nitrogen adsorption test, nitrogen was adsorbed to or desorbed from the respective powder, and from the difference between the amount of the adsorbed nitrogen and the amount of the desorbed nitrogen, a specific surface area, a pore volume, and a pore size distribution were obtained. In detail, from an N2 adsorption-desorption isotherm which was obtained by the nitrogen adsorption test, the specific surface area of a pore was calculated by using a Brunauer-Emmett-Teller (BET) method, the whole volume of the pore was directly deduced from the Y axis of the N2 adsorption-desorption graph, and the pore size distribution was obtained by using the Barrett-Joyner-Halenda (BJH) method. The results thereof are shown in Table 3 below, FIG. 12 (the active materials of Comparative Example 1 and Examples 1 to 4), and FIG. 13 (the active materials of Comparative Example 8 and Examples 7 to 10):
[Table 3]
 Core componentSpecific surface area (m2/g)Total pore volume (mL/g)First pore peak (nm)Second pore peak (nm)
Comparative Example 1 SnO2 112 0.25 2.9 15.6
Example 1 SnO2 98 0.28 2.6 17.8
Example 2 SnO2 107 0.28 2.5 17.9
Example 3 SnO2 109 0.26 2.4 15.4
Example 4 SnO2 97 0.25 2.4 15.4
Comparative Example 8 MoO2 115 0.57 1.7 18.2
Example 7 MoO2 118 0.46 1.7 17.6
Example 8 MoO2 110 0.46 1.7 16.5
Example 9 MoO2 91 0.47 · 16.5
Example 10 MoO2 50 0.25 · 18.0


[0133] Referring to FIGS. 12 and 13, the active materials have bimodal size distributions having two pore diameter peaks (pore size distribution). Accordingly, it was confirmed that the active materials of Examples 1 to 4 and 7 to 10 maintain their nano-porous structures even after a carbon thin film was formed.

Evaluation Example 4: Raman spectrum evaluation



[0134] Raman spectra of the carbon thin films of the active materials of Comparative Example 2, Example 5, Example 6, Example 3, and Comparative Example 6 were evaluated, and results thereof are shown in Table 4 below and FIGS. 14 and 15.
[Table 4]
 Comparative Example 2Example 5Example 6Example 3Comparative Example 6
Ratio of Peak D area/peak G area (AD/AG) 1.95 1.81 1.59 1.64 2.27
Ratio of Peak D intensity/peak G intensity (ID/IG) 0.78 0.63 0.60 0.58 0.83


[0135] Referring to Table 4, AD/AG and ID/IG of Comparative Examples 2 and 6 are smaller than AD/AG and ID/IG of Examples 5, 6 and 3. Accordingly, it was confirmed that the carbon thin films of Examples 5, 6 and 3 have better crystallinity than the carbon thin films of Comparative Examples 2 and 6.

Evaluation Example 5: Differential Scanning Calorimetry Analysis



[0136] A thermogravimetric analysis (TGA) was performed on the active materials of Comparative Example 1 and Examples 1 to 4 and results thereof are shown in FIG. 16. The TGA was performed using an SDT2960 manufactured by TA instruments Co., Ltd. Referring to FIG. 16, the mass decrease between 300°C and 700°C seems to correspond to a mass decrease of carbon (assuming that a mass decrease at a temperature of 300°C or lower corresponds to a mass decrease of water and impurities and a mass decrease at a temperature of 700°C or more corresponds to a mass decrease caused by phase transition in a reducing atmosphere at a high temperature). Accordingly, it was confirmed with reference to FIG. 16 that the active materials of Examples 1 to 4 include a carbon thin film.

Evaluation Example 6: Conductivity Evaluation



[0137] Conductivity of the active materials of pore-free SnO2 core being a spherical particle (product of Aldrich Co., Ltd, SnO2 particles having an average particle size of about 100 nm or less), Comparative Example 2, Example 5, Comparative Example 1, Comparative Example 5, and Example 3 were evaluated with respect to pressure by using a powder resistance measurement system LORESTA series (MCP-PD51), and results thereof are shown in FIGS. 17 and 18.

[0138] Referring to FIG. 17, it was confirmed that conductivity of the active material of Example 5 is higher than conductivity of the pore-free SnO2 core being a spherical particle and the active material of Comparative Example 2.

[0139] Referring to FIG. 18, it was confirmed that conductivity of the active material of Example 3 is higher than conductivity of the active materials of Comparative Examples 1 and 5. From these results, it was confirmed that when a carbon thin film is formed, conductivity of the active material of Example 3 is improved while the nano-structure of the porous core is maintained.

Evaluation Example 7: Charge and Discharge Characteristics Evaluation (Manufacture of negative electrode and lithium battery)



[0140] 70 mg of the active material powder of Comparative Example 1, 15 mg of a carbon conducting agent (Super-P, Timcal Inc.), and 15 mg of a binder (polyamide/imide, PAI) were mixed with 15 mL of N-methylpyrrolidone (NMP) in an agate mortar to prepare a slurry. The slurry was applied on a copper current collector to a thickness of about 50µm by using a doctor blade, followed by drying at room temperature for 2 hours and then drying under a vacuum condition at a temperature of 200°C for 2 hours to prepare a negative electrode plate.

[0141] A standard coin cell was manufactured using the negative electrode plate, lithium metal as a counter electrode, a polypropylene separator (Cellgard® 3510) as a separator, and a solution of 1.3 M LiPF6 dissolved in a mixed solution including ethylene carbonate (EC) and diethyl carbonate (DEC)(3:7 weight ratio) as an electrolyte.

[0142] Coin cells were manufactured by using the same method, except that instead of the active material of Comparative Example 1, active materials of Examples 1 to 4, Comparative Example 8 and Examples 7 to 10 were used.

(Charge and Discharge Test)



[0143] Lithium batteries including the active materials of Comparative Example 1, Examples 1 to 4, Comparative Example 8 and Examples 7 to 10 were charged with a current of 100 mA per 1 g of the respective active materials until the voltage reached 0.001 V (vs. Li) and then, with the same amplitude of current, discharging was performed until the voltage reached 2 V (vs. Li). Consequentially, within the same current and voltage ranges, charging and discharging were repeatedly performed 100 times.

[0144] FIG. 19 shows charge and discharge results of the lithium batteries including the active materials respectively of Comparative Example 1 and Example 3 in the first and fifth cycles. FIG. 20 is a graph of a capacity maintenance rate of the lithium batteries including respectively the active materials of Comparative Example 1 and Examples 1 to 4. FIG. 21 is a graph of a capacity maintenance rate of the lithium batteries including the active materials respectively of Comparative Example 8 and Examples 7 to 10. The capacity maintenance rates (%) of FIGS. 20 and 21 were calculated by an equation "(discharge capacity after the respective cycles/ initial discharge capacity) x 100."

[0145] Also, the density of the negative electrode, capacity per g, capacity per cc, an initial efficiency, and 100 cycle lifetime ([discharge capacity after 100 cycles / initial discharge capacity] x 100 (%)) of each of the lithium batteries including the active materials of Comparative Example 1, Examples 1 to 4, Comparative Example 8, and Examples 7 to 10 are shown in Table 5 below. However, in Table 5, in the case of the lithium battery including the active material of Comparative Example 1, a 50 cycle lifetime ([discharge capacity after 50 cycles/ initial discharge capacity] x 100 (%)) is shown.
[Table 5]
Negative active materialDensity (g/m2)Capacity per g (mAh/g)Capacity per CC (mAh/CC)Initial efficiency (%)100 cycle lifetime (%)
Comparative Example 1 1.89 751.2 925.6 46.31 56.1 (50 cycle lifetime)
Example 1 1.94 743.3 1048.4 45.84 80.9
Example 2 2.10 693.1 1126.6 42.14 92.6
Example 3 2.09 662.5 973.2 42.07 95.4
Example 4 2.32 672.4 1092.9 40.72 103.9
Comparative Example 6 1.58 1207.28 1332.37 68.86 64.30
Example 7 1.63 1106.16 1264.48 69.51 82.50
Example 8 1.55 1064.27 1154.63 68.59 87.20
Example 9 1.52 1038.76 1102.79 70.07 87.87
Example 10 1.57 1014.84 1114.23 68.25 83.65


[0146] Referring to FIGS. 20 and 21 and Table 5, it is confirmed that the lithium batteries including the negative electrodes including the active materials of Examples 1 to 4 and Examples 7 to 10 have better capacity and lifetime characteristics than the lithium batteries including the negative electrodes including the active materials of Comparative Example 1 and 8.

[0147] As described above, according to the one or more of the above embodiments of the present invention, lithium batteries including the electrode active materials show excellent capacity and lifetime characteristics.

[0148] It should be understood that the exemplary embodiments described therein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

[0149] Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles of the invention, the scope of which is defined in the claims.


Claims

1. An electrode active material comprising: a porous core (12) comprising at least a metal oxide comprising at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide, and bismuth oxide which enable intercalation and deintercalation of lithium ions; and
a crystalline carbon thin film (14) having a thickness of 2 nm or less that is formed on at least a portion of a surface of the porous core (12);
characterised in that the electrode active material (10) is in the form of a particle comprising pores (16) and a skeleton that forms walls between adjacent pores (16), wherein at least one of the size of the particle, the average size of the pores (16) and the thickness of the skeleton have a nano-size.
 
2. The electrode active material of claim 1, wherein the pores (16) are connected to each other to form a channel.
 
3. The electrode active material of claim 1 or 2, wherein the porous core (12) comprises at least one of SnO2 and MoO2.
 
4. The electrode active material of any one of claims 1 to 3, wherein the peak intensity ratio of ID/IG is 0.7 or lower,
wherein in a Raman spectrum of the crystalline carbon thin film (14), ID represents an intensity of peak D that is present at a wave number of 1360±10 cm-1 and IG represents an intensity of peak G that is present at a wave number of 1580±10 cm-1.
 
5. The electrode active material of any one of claims 1 to 4, wherein B/A is 7.69 x 10-3 g2/m2 or less,
A represents the specific surface area of the porous core (12), and B represents the mass of the carbon thin film (14).
 
6. An electrode comprising the electrode active material (10) of any one of claims 1 to 5.
 
7. A lithium battery comprising the electrode of claim 6.
 
8. A method of preparing the electrode active material (10) of claim 1, the method being characterised by comprising:
forming a self-assembled monolayer of a carbon-based precursor compound according to Formula 2 below on at least a portion of the surface of the porous core (12) including at least a metal oxide comprising at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide, and bismuth oxide that enable intercalation and deintercalation of lithium ions by:

mixing i) the porous core (12), ii) a carbon-containing precursor compound according to Formula 1 below, and iii) a solvent to form a self-assembled monolayer of the compound according to Formula 2 on said surface; and

converting the monolayer into the crystalline carbon thin film (14) having a thickness of 2 nm or less by heating in an inert atmosphere the porous core (12) on which the self-assembled monolayer is formed;

wherein in Formulae 1 and 2,

A is a substituted or unsubstituted C5-C30 aromatic ring or a substituted or unsubstituted C2-C30 heteroaromatic ring;

a and b are each independently an integer of 1 to 5; and

* denotes a binding site with the surface of the porous core (12).


 
9. The method of claim 8, wherein the ring A is a substituted or unsubstituted benzene, a substituted or unsubstituted pentalene, a substituted or unsubstituted indene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted azulene, a substituted or unsubstituted heptalene, a substituted or unsubstituted indacene, a substituted or unsubstituted acenaphthylene, a substituted or unsubstituted fluorene, a substituted or unsubstituted phenalene, a substituted or unsubstituted phenanthrene, a substituted or unsubstituted anthracene, a substituted or unsubstituted fluoranthene, a substituted or unsubstituted triphenylene, a substituted or unsubstituted pyrene, a substituted or unsubstituted chrysene, a substituted or unsubstituted naphthacene, a substituted or unsubstituted picene, a substituted or unsubstituted perylene, a substituted or unsubstituted pentaphene, a substituted or unsubstituted hexacene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted imidazole, a substituted or unsubstituted imidazopyridine, a substituted or unsubstituted imidazopyrimidine, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted indole, a substituted or unsubstituted purine, a substituted or unsubstituted quinoline, a substituted or unsubstituted phthalazine, a substituted or unsubstituted indole, a substituted or unsubstituted naphthyridine, a substituted or unsubstituted quinazoline, a substituted or unsubstituted cinnoline, a substituted or unsubstituted indazole, a substituted or unsubstituted carbazole, a substituted or unsubstituted phenazine, a substituted or unsubstituted phenanthridine, a substituted or unsubstituted triazine, a substituted or unsubstituted phenanthroline, or a substituted or unsubstituted quinoxaline.
 
10. The method of claim 8 or 9, wherein the ring A is benzene, naphthalene, phenalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphene, hexacene, pyridine, pyrazine, pyrimidine, pyridazine, quinoline, phthalazine, quinoxaline, quinazoline, cinnoline, phenanthridine, phenanthroline, or phenazine, and a and b each are 1 or 2.
 


Ansprüche

1. Elektrodenaktivmaterial, umfassend: einen porösen Kern (12), umfassend mindestens ein Metalloxid, umfassend mindestens eines aus Zinnoxid, Eisenoxid, Kobaltoxid, Nickeloxid, Zinkoxid, Manganoxid, Molybdenumoxid und Bismuthoxid, die die Einlagerung und Auslagerung von Lithiumionen ermöglichen; und
einen kristallinen Carbondünnfilm (14) mit einer Dicke von 2 nm oder weniger, der auf mindestens einem Teil einer Oberfläche des porösen Kerns (12) geformt ist;
dadurch gekennzeichnet, dass das Elektrodenaktivmaterial (10) in Form eines Poren (16) umfassenden Partikels und eines Wände zwischen benachbarten Poren (16) formenden Gerüst vorliegt, wobei mindestens eine der Größe des Partikels, der durchschnittlichen Größe der Poren (16) und der Dicke des Gerüsts eine Nanogröße aufweist.
 
2. Elektrodenaktivmaterial nach Anspruch 1, wobei die Poren (16) miteinander verbunden sind, um einen Kanal zu formen.
 
3. Elektrodenaktivmaterial nach Anspruch 1 oder 2, wobei der poröse Kern (12) mindestens eines aus SnO2 und MoO2 umfasst.
 
4. Elektrodenaktivmaterial nach einem der Ansprüche 1 bis 3, wobei das Spitzenintensitätsverhältnis von ID/IG 0,7 oder niedriger ist,
wobei ein Raman-Spektrum des Carbondünnfilms (14), ID, eine Intensität der Spitze D repräsentiert, die bei einer Wellenanzahl von 1360±10 cm-1 vorliegt, und IG eine Intensität der Spitze G repräsentiert, die bei einer Wellenanzahl von 1580±10 cm-1 vorliegt.
 
5. Elektrodenaktivmaterial nach einem der Ansprüche 1 bis 4, wobei B/A 7,69 x 10-3 g2/m2 oder weniger ist,
A die spezifische Oberflächenfläche des porösen Kerns (12) repräsentiert und B die Masse der Carbondünnfilms (14) repräsentiert.
 
6. Elektrode, umfassend das Elektrodenaktivmaterial (10) nach einem der Ansprüche 1 bis 5.
 
7. Lithiumbatterie, umfassend die Elektrode nach Anspruch 6.
 
8. Verfahren zum Herstellen des Elektrodenaktivmaterials (10) nach Anspruch 1, wobei das Verfahren dadurch gekennzeichnet ist, dass es umfasst:
Formen einer selbst-montierten Einfachschicht einer carbonbasierten Vorläuferverbindung nach der unten stehenden Formel 2 auf mindestens einem Teil der Oberfläche des porösen Kerns (12), enthaltend mindestens ein Metalloxid, umfassend mindestens eines aus Zinnoxid, Eisenoxid, Kobaltoxid, Nickeloxid, Zinkoxid, Manganoxid, Molybdenumoxid und Bismuthoxid, die die Einlagerung und Auslagerung von Lithiumionen ermöglichen, durch:

Mischen i) des porösen Kerns (12), ii) einer carbonhaltigen Vorläuferverbindung nach der unten stehenden Formel 1, und iii) eines Lösemittels einer selbst-montierten Einfachschicht der Verbindung nach Formel 2 auf der Oberfläche; und

Konvertieren der Einfachschicht in den kristallinen Carbondünnfilm (14) mit einer Dicke von 2 nm oder weniger durch Heizen des porösen Kerns (12), auf dem die selbst-montierte Einfachschicht geformt ist, in Inertgasatmosphäre;

wobei in Formel 1 und 2,

A ein substituierter oder nicht-substituierter aromatischer C5-C30-Ring oder ein substituierter oder nicht-substituierter heteroaromatischer C2-C30 Ring ist;

a und b jeweils unabhängig eine ganze Zahl von 1 bis 5 sind; und

* eine Bindestelle mit der Oberfläche des porösen Kerns (12) bezeichnet.


 
9. Verfahren nach Anspruch 8, wobei Ring A ein substituiertes oder unsubstituiertes Benzol, ein substituiertes oder unsubstituiertes Pentalen, ein substituiertes oder unsubstituiertes Inden, ein substituiertes oder unsubstituiertes Naphthalen, ein substituiertes oder unsubstituiertes Azulen, ein substituiertes oder unsubstituiertes Heptalen, ein substituiertes oder unsubstituiertes Indacen, ein substituiertes oder unsubstituiertes Acenaphthylen, ein substituiertes oder unsubstituiertes Fluoren, ein substituiertes oder unsubstituiertes Phenalen, ein substituiertes oder unsubstituiertes Phenanthren, ein substituiertes oder unsubstituiertes Anthracen, ein substituiertes oder unsubstituiertes Fluoranthen, ein substituiertes oder unsubstituiertes Triphenylen, ein substituiertes oder unsubstituiertes Pyren, ein substituiertes oder unsubstituiertes Chrysen, ein substituiertes oder unsubstituiertes Naphthacen, ein substituiertes oder unsubstituiertes Picen, ein substituiertes oder unsubstituiertes Perylen, ein substituiertes oder unsubstituiertes Pentaphen, ein substituiertes oder unsubstituiertes Hexacen, ein substituiertes oder unsubstituiertes Pyrrol, ein substituiertes oder unsubstituiertes Pyrazol, ein substituiertes oder unsubstituiertes Imidazol, ein substituiertes oder unsubstituiertes Imidazopyridin, ein substituiertes oder unsubstituiertes Imidazopyrimidin, ein substituiertes oder unsubstituiertes Pyridin, ein substituiertes oder unsubstituiertes Pyrazin, ein substituiertes oder unsubstituiertes Pyrimidin, ein substituiertes oder unsubstituiertes Pyridazin, ein substituiertes oder unsubstituiertes Indol, ein substituiertes oder unsubstituiertes Purin, ein substituiertes oder unsubstituiertes Chinolin, ein substituiertes oder unsubstituiertes Phthalazin, ein substituiertes oder unsubstituiertes Indol, ein substituiertes oder unsubstituiertes Naphthyridin, ein substituiertes oder unsubstituiertes Chinazolin, ein substituiertes oder unsubstituiertes Cinnolin, ein substituiertes oder unsubstituiertes Indazol, ein substituiertes oder unsubstituiertes Carbazol, ein substituiertes oder unsubstituiertes Phenazin, ein substituiertes oder unsubstituiertes Phenanthridin, ein substituiertes oder unsubstituiertes Triazin, ein substituiertes oder unsubstituiertes Phenanthrolin oder ein substituiertes oder unsubstituiertes Chinoxalin ist.
 
10. Verfahren nach Anspruch 8 oder 9, wobei Ring A Benzol, Naphthalen, Phenalen, Phenanthren, Anthracen, Triphenylen, Pyren, Chrysen, Naphthacen, Picen, Perylen, Pentaphen, Hexacen, Pyridin, Pyrazin, Pyrimidin, Pyridazin, Chinolin, Phthalazin, Chinoxalin, Chinazolin, Cinnolin, Phenanthridin, Phenanthrolin oder Phenazin ist und a und b jeweils 1 oder 2 sind.
 


Revendications

1. Matériau actif d'électrode comprenant : un noyau poreux (12) comprenant au moins un oxyde de métal comprenant au moins l'un des suivants : oxyde d'étain, oxyde de fer, oxyde de cobalt, oxyde de nickel, oxyde de zinc, oxyde de manganèse, oxyde de molybdène et oxyde de bismuth, permettant l'intercalation et la désintercalation d'ions de lithium ; et
une pellicule mince de carbone cristallin (14) mesurant 2 nm ou moins d'épaisseur, formée sur au moins une partie d'une surface du noyau poreux (12) ;
caractérisé en ce que le matériau actif d'électrode (10) se présente sous forme d'une particule comprenant des pores (16) et d'un squelette formant des parois entre des pores adjacents (16), au moins une de la taille de la particule, de la taille moyenne des pores (16) et de l'épaisseur du squelette étant de taille nanométrique.
 
2. Matériau actif d'électrode selon la revendication 1, les pores (16) étant connectés entre eux pour former un canal.
 
3. Matériau actif d'électrode selon la revendication 1 ou 2, le noyau poreux (12) comprenant au moins un des suivants : SnO2 et MoO2.
 
4. Matériau actif d'électrode selon une quelconque des revendications 1 à 3, le taux d'intensité de crête de ID/IG étant égal à 0,7 ou inférieur,
dans lequel, dans un spectre de raman de la pellicule mince de carbone cristallin (14), ID représente une intensité de crête D présente à un nombre d'onde égal à 1360±10 cm-1 et IG représente une intensité de crête G présente à un nombre d'onde égal à 1580±10 cm-1.
 
5. Matériau actif d'électrode selon une quelconque des revendications 1 à 4, B/A étant égal à 7,69 x 10-3 g2/m2 ou moins,
A représentant la superficie spécifique du noyau poreux (12), et B représentant la masse de la pellicule mince de carbone (14).
 
6. Électrode comprenant le matériau actif d'électrode (10) selon une quelconque des revendications 1 à 5.
 
7. Accumulateur au lithium comprenant l'électrode selon la revendication 6.
 
8. Méthode de préparation du matériau actif d'électrode (10) selon la revendication 1, la méthode étant caractérisée en ce qu'elle comprend :
la formation d'une monocouche auto-assemblée d'un composé précurseur à base de carbone selon la Formule 2 ci-dessous sur au moins une partie de la surface du noyau poreux (12) comprenant au moins un oxyde de métal comprenant au moins un des suivants : oxyde d'étain, oxyde de fer, oxyde de cobalt, oxyde de nickel, oxyde de zinc, oxyde de manganèse, oxyde de molybdène et oxyde de bismuth, permettant l'intercalation et la désintercalation d'ions de lithium par :

le mélange i) du noyau poreux (12), ii) d'un précurseur contenant du carbone, conformément à la formule 1 ci-dessous, et iii) d'un solvant pour former une monocouche auto-assemblée du composé, conformément à la formule 2, sur ladite surface ; et

la conversion de la monocouche dans la pellicule mince de carbone cristallin (14) d'une épaisseur de 2 nm ou moins, en chauffant, en atmosphère inerte, le noyau poreux (12) sur lequel est formée la monocouche auto-assemblée ;

dans laquelle, dans les formules 1 et 2,

A est un cycle aromatique substitué ou non substitué C5-C30, ou un cycle hétéro-aromatique substitué ou non substitué C2-C30 ;

a et b sont chacun un nombre entier compris entre 1 et 5 ; et

* dénote un site de liaison avec la surface du noyau poreux (12).


 
9. Méthode selon la revendication 8, le cycle A étant un benzène substitué ou non substitué, un pentalène substitué ou non substitué, un indène substitué ou non substitué, un naphtalène substitué ou non substitué, un azulène substitué ou non substitué, un heptalène substitué ou non substitué, un indacène substitué ou non substitué, un acénaphtylène substitué ou non substitué, un fluorène substitué ou non substitué, un phénalène substitué ou non substitué, un phénanthrène substitué ou non substitué, un anthracène substitué ou non substitué, un fluoranthène substitué ou non substitué, un triphénylène substitué ou non substitué, un pyrène substitué ou non substitué, un chrysène substitué ou non substitué, un naphthacène substitué ou non substitué, un picène substitué ou non substitué, un pérylène substitué ou non substitué, un pentaphène substitué ou non substitué, un hexacène substitué ou non substitué, un pyrrole substitué ou non substitué, un pyrazole substitué ou non substitué, un imidazole substitué ou non substitué, une imidazopyridine substituée ou non substituée, une imidazopyrimidine substituée ou non substituée, un pyridine substitué ou non substitué, une pyrazine substituée ou non substituée, une pyrimidine substituée ou non substituée, une pyridazine substituée ou non substituée, un indole substitué ou non substitué, une purine substituée ou non substituée, une quinoline substituée ou non substituée, une phthalazine substituée ou non substituée, un indole substitué ou non substitué, une naphthyridine substituée ou non substituée, une quinazoline substituée ou non substituée, une cinnolline substituée ou non substituée, un indazole substitué ou non substitué, un carbazole substitué ou non substitué, une phénazine substituée ou non substituée, une phenanthridine substituée ou non substituée, une triazine substituée ou non substituée, une phénanthroline substituée ou non substituée, ou une quinoxaline substituée ou non substituée.
 
10. Méthode selon la revendication 8 ou 9, le cycle A étant du benzène, de la naphthalène, du phénalène, du phénanthrène, de l'anthracène, du triphénylène, du pyrène, du chrysène, du naphthacène, du picène, du pérylène, du pentaphène, de l'hexacène, de la pyridine, de la pyrazine, de la pyrimidine, de la pyridazine, de la quinoline, de la phthalazine, de la quinoxaline, de la quinazoline, de la cinnoline, de la phénanthridine, de la phénanthroline, ou de la phénazine, et a et b étant chacun 1 ou 2.
 




Drawing

































































Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description




Non-patent literature cited in the description