Technical Field
[0001] The present invention relates to non-aqueous secondary lithium-ion electrochemical
cells and batteries.
Background Art
[0002] Lithium-ion batteries are considered to be the rechargeable batteries of the future
for portable electronics to aerospace to vehicular applications. In a known construction
for a lithium-ion battery, carbon or graphite is used as an anode, a lithiated transition
metal intercalation compound is used as a cathode and LiPF
6 is used as an electrolyte in carbonate-based nonaqueous solvents.
[0003] The electrochemical process is the uptake of lithium ions at the anode during charge
and their release during discharge, rather than lithium plating and stripping as occurs
in metallic lithium rechargeable battery systems. As metallic lithium is not present
in the cell, lithium-ion cells have enhanced safety and a longer cycle life than the
cells containing metallic lithium.
[0004] At present, disordered carbon (hard carbon) and ordered carbon (graphite) are used
as anodes in commercial lithium-ion batteries. The carbonaceous materials can deliver
a reversible specific capacity of 372 mAh/g, corresponding to the chemical formula
LiC
6 as compared to 3830 mAh/g for metallic lithium. The practical reversible capacity
of these carbonaceous materials is even lower in the range of 300-340 mAh/g.
[0005] Other carbonaceous materials, also of disordered structure and are known as "soft
carbon", of high reversible capacity have been prepared by pyrolysis of suitable starting
materials.
Sato et al (Science, 264, 556, 1994) disclosed a carbonaceous material prepared by heating polyparaphenylene at 700°C
which has a reversible capacity of 680 mAh/g.
Mabuchi et al (Seventh International Meeting on Lithium Batteries, Extended Abstracts,
Page 212, Boston, Massachusetts, 1994) disclosed a low density carbonaceous material prepared by heating coal tar pitch
at 700°C which has a reversible capacity of about 750 mAh/g.
Yamada et al (U. S. Patent, 5,834,138, Nov. 10, 1998) disclosed a carbonaceous material prepared by heat treatment of coffee beans, tea
leaves, corns, etc. at 1100-1200°C. The carbonaceous material delivers a reversible
capacity of 500 mAh/g.
[0006] These values of reversible capacities are much greater than that of the carbonaceous
materials used in commercial lithium-ion cells. However, low density and very high
irreversible capacity loss of the above carbonaceous materials limit their commercial
use as anodes for lithium-ion batteries.
[0007] It has been suggested that the reversible capacity of anodes formed of carbonaceous
materials can be increased by the addition of other elements to the carbonaceous materials.
For example, the addition of small amounts of phosphorous (European Patent Application
No.
EP 486950) and boron (Japanese Application Laid-Open No.
03-245458) are alleged to enhance the specific capacity of a carbonaceous anode. Moreover,
Canadian Application Serial No.
2,098,248 discloses that substituting electron acceptors (such as boron, aluminum, etc.) for
carbon atoms in the structure of the carbonaceous materials will enhance anode capacity.
Toyoguchi (Japanese Publication No.
10-05299) discloses a secondary battery that includes a carbide compound containing an alkali
metal in a charged state. Saito (Japanese Publication No.
06-290782) discloses an electrolyte leak proof secondary battery containing an electrode material
consisting of at least one carbide of chromium, silicon, colbalt, zirconium, tungsten,
germanium, tantalum, titanium, iron, niobium, nickel, vanadium, boron, halfnium, and
molybdenum.
Nagamine et al. (U.S. Patent No. 5,932,373) disclose a non-aqueous electrolyte secondary cell comprising (i) a positive electrode
including a lithium-transition metal composite oxide material, (ii) a negative electrode
including a graphite material prepared by carbonizing an organic compound to form
a carbide, and (iii) an electrolyte solution comprising a lithium salt dissolved in
a non-aqueous solvent.
Okamura et al. (Japanese Publication No. 10-112316) disclose a non-aqueous electrolyte secondary battery for portable equipment, wherein
the negative electrode comprises a carbide material of formula M
XC wherein x = 1-4 and M is a transition metal element substituted by Li. The negative
electrode is made by mixing metal carbide with polyvinylidene fluoride as a binding
agent.
Bito et al (U.S. Patent No. 5,939,224) disclose a nonaqueous electrolyte secondary battery employing a carbide containing
an alkali metal in a charged stage as a negative electrode active material wherein
the carbide is an ionic bond type carbide, a covalent bond type carbide, or an intermetallic
compound.
Choi et al (U.S. Publication No. 2002-0012845 A1) disclose a negative active material for rechargeable lithium battery and a method
of preparing the same, wherein the negative active material comprises crystalline
carbon having a dispersed element serving as graphitization catalyst selected from
the group consisting of transition metals, alkaline metals, alkaline earth metals,
semi-metals of Group 3A, Group 3B, Group 4A and Group 4B of the periodic table, elements
of Group 5A, and elements of Group 5B, and carbides thereof.
Sheem et al (U.S. Patent No. 6,355,377 Bl) disclose a negative active material for a rechargeable lithium battery comprising
a crystalline carbon core, and semi-crystalline carbon shell including metal boride
and metal carbide serving as graphitization catalyst and changing the structure of
the surrounding carbon.
Idota et al (U.S. Patent No. 5,686,203) disclose a non-aqueous secondary battery comprising a positive electrode, a negative
electrode and a non-aqueous electrolyte. The electrode mixture for positive electrode
contains the positive electrode active material comprising a compound in which anions
can be inserted and at least one member selected from group consisting of transition
metals, elements of Group IIIB and IVB (except C) and carbides thereof.
Disclosure of Invention
[0008] The present invention provides a new and different concept for enhancing the reversible
capacity of the carbonaceous material forming the active material of an anode in a
lithium ion cell or battery. Specifically, the present invention provides a lithium-ion
cell in which molybdenum carbide is combined with the carbonaceous material of the
anode to enhance the reversible capacity of the carbonaceous material. This concept
is also believed to promote the development of high specific energy and energy density
lithium-ion cells and batteries.
[0009] Accordingly, it is the principal objective of the present invention to improve the
reversible capacity of carbonaceous material forming the active material of an anode
of a lithium-ion cell or battery.
[0010] Another objective of the present invention is to provide a novel and improved rechargeable
lithium-ion cell and/or battery having high specific energy and energy density.
[0011] Further features of the present invention will become apparent from the following
detailed description and the accompanying drawings.
Brief Description of the Drawings
[0012] Illustrative and presently preferred embodiments of the invention are shown in the
accompanying drawing in which:
Figure 1 is a graph representing the discharge charge characteristics of a carbonaceous
material containing 8% molybdenum carbide additive in demonstrating the principle
of the present invention;
Figure 2 is a graph representing the charge capacity of a carbonaceous material containing
8% molybdenum carbide additive in demonstrating the principles of the present invention;
Figure 3 is a graph representing the discharge charge characteristics of a carbonaceous
material without molybdenum carbide;
Figure 4 is a graph representing the charge capacity of a carbonaceous material without
molybdenum carbide;
Figure 5 shows the cycling behavior of a lithium-ion cell made with molybdenum carbide
added to carbonaceous anode material, in accordance with the present invention;
Figure 6 shows the cycling behavior of a lithium-ion cell made in accordance with
known prior techniques; and
Figure 7 is a schematic representation of a lithium-ion cell (both in assembled and
exploded stages) embodying an anode in accordance with the present invention.
Best Mode for Carrying Out the Invention
[0013] According to the present invention, a lithium-ion cell or battery comprises a negative
electrode (anode) formed of carbonaceous materials combined with molybdenum carbide
in an amount of less than 20% (by weight), and a positive electrode (cathode) containing
LiCoO
2, LiNiCoO
2, LiNiCoAlO
2, LiNiO
2, LiMn
2O
4, LiMnO
2, LiV
2O
5, LiV
6O
13, LiTiS
2, Li
3FeN
2, Li
7VN
4 or combinations of these materials. The substrates for the negative and positive
electrodes are preferably copper and aluminum foils, respectively.
[0014] The electrolyte used in a lithium-ion cell and/or battery of the present invention
is a non-aqueous aprotic organic electrolyte and preferably a non-aqueous solution
consisting of a solute, such as LiPF
6, LiBF
4, LiASF
6, LiCF
3SO
3, LiN(CF
3SO
2)
2 or LiClO
4, dissolved in a solvent such as propylene carbonate, ethylene carbonate, diethyl
carbonate, ethyl methyl carbonate, and dimethyl carbonate as well as combinations
of such materials.
[0015] The high reversible capacity of the lithium-ion cell or battery embodying an anode
made of carbonaceous material combined with molybdenum carbide, in accordance with
the present invention, provides ease of cell balance with high capacity cathode and
results in a high capacity and high energy density lithium-ion cell. The present invention,
however, is not limited to that theory. Suffice it to say, as shall become more apparent
in the following Examples, it has been surprisingly discovered that a significant
improvement in performance, beyond what might normally be expected, is possible with
the lithium-ion cell and/or battery of the present invention.
[0017] A preferred form of lithium-ion cell embodying a carbonaceous anode combined with
molybdenum carbide is shown at 101 in Figure 7. The assembled cell 101 is shown with
the anode, cathode, and electrolyte not shown but enclosed in a sealed sandwich structure
with the anode electrically accessible by means of protruding conductive copper tab
102 and the lithiated intercalation compound cathode electrically accessible by means
of a protruding conductive aluminum tab 103. The anode and cathode of the assembled
cell 101 are separated by a porous separator that is permeated with an aprotic non-aqueous
electrolyte that is in effective contact with both the anode and cathode.
[0018] More specifically, as shown in the exploded component portion of Figure 7, a pair
of one-sided anodes 104A and 104B and a two-sided cathode 105, are configured to be
assembled as a sandwich (cell 101) with the two-sided cathode 105 positioned between
and separated from the respective anodes 104A and 104B by respective porous separators
106A and 106B that are permeated with an aprotic, non-aqueous electrolyte that is
in effective contact with both the cathode and the facing anodes. Conductive copper
tabs 102A and 102B are provided for the respective anodes 104A and 104B and an aluminum
tab 103A is provided for the two-sided cathode 105, whereby the respective electrodes
of the cell 101 are electrically accessible when assembled as a sandwich and enclosed
within a sealed enclosure (not shown).
[0019] In the cell 101, the anodes 104A, 104B each comprises carbonaceous material (e.g
of an ordered carbon such as graphite, or of a disordered carbon such as 'soft carbon'
combined with molybdenum carbide and supported by a copper foil substrate. The cathode
105 may be formed of LiCoO
2, LiNiCoO
2, LiNiCoAlO
2, LiNiO
2, LiMn
2O
4, LiMnO
2, LiV
2O
5, LiV
6O
13, LiTiS
2, Li
3FeN
2, Li
7VN
4 or a combination of such materials, supported by an aluminum foil substrate. The
respective anode and cathode electrodes are maintained spaced from one another by
a respective electrically non-conductive separator that is permeable whereby the aprotic,
non-aqueous electrolyte is carried by the separators 106A, 106B, and maintained in
effective electrochemical contact with both the cathode and facing anode. The permeable
separators may each be formed of a micro-porous poly-olefin film.
[0020] Although the respective anodes and cathodes of the cell 101 are shown as flat plates,
it is to be understood that other configuration can be used, such as spiral or so-called
jelly-roll configuration, wherein the respective anode and cathode electrodes are
nevertheless maintained physically and electrically spaced from one another by a permeable
spacer that carries the electrolyte and maintains it in effective electrochemical
contact with the respective anode and cathode surfaces.
[0021] Moreover, there are different ways to form the anode of carbonaceous material and
to combine the carbonaceous material with molybdenum carbide. For example, one way
of combining the carbonaceous material with molybdenum carbide is to thoroughly mix
molybdenum carbide with the carbonaceous material. Another way is to add molybdenum
compound to carbonaceous material and heat-treat to convert the added molybdenum compound
to molybdenum carbide. The present invention is directed to an anode for a lithium
ion cell, in which carbonaceous material is combined with molybdenum carbide, but
is not intended to be limited to any particular way of combining the carbonaceous
material with the molybdenum carbide.
[0022] Also, it should be noted that it is preferred that a relatively small amount (by
weight) of the molybdenum carbide is combined with the carbonaceous material. More
specifically, it is preferred that the molybdenum carbide be in the range of 0.1 %
to 15% (by weight). In addition, it is preferred that the particle size of molybdenum
carbide in the second electrode is in the range of 0.05 µm to 3 µm.
[0023] It is to be understood that a plurality of electrochemical cells as described above
can be used to assemble a battery of such cells by connecting the respective electrodes
of the assembly of cells in an electrical circuit defining a battery (in a known manner)
to produce a battery with the voltage or current characteristics as determined by
the number of cells connected in series or parallel circuit relationship.
[0024] The following specific examples are given to illustrate the practice of the invention,
but are not to be considered as limiting in any way. Examples 1 and 2 demonstrate
the proof of principle of the present invention, and Examples 3, cells B1 and B2,
and the first cell described in Example 4 (whose performance is illustrated in Figure
5) relate to lithium ion cells made according to the principles of the present invention.
Examples 1
[0025] 0.465 g of molybdenum carbide (of particle size of about 1µm) obtained from Climax
Molybdenum Company, Tucson, Arizona was thoroughly mixed with 5.00 g of S26813 graphite
obtained from Superior Graphite Co, Chicago, Illinois. The mixture was then used as
the active material of the working electrode of a half-cell to evaluate the concept
of the present invention. The half-cell included a working electrode made from the
mixture of the graphite and molybdenum carbide, a metallic lithium counter electrode
and 1M LiPF
6 electrolyte in a mixture (2:1 w/w) of ethylene carbonate/dimethyl carbonate (EC/DMC)
solvents. A micro-porous poly-olefin (Celgard 2400) separator was used in between
the working and counter electrodes to isolate them electronically. A slurry of the
graphite-molybdenum carbide mixture and 6% poly(vinyledene fluoride) was prepared
in dimethyl formamide (DMF) and coated on to a copper foil to make the working electrode.
The counter electrode was made of metallic lithium of 50 µm thick press fitted to
the expanded nickel mesh substrate.
[0026] The aprotic, non-aqueous 1M LiPF
6 electrolyte mixture permeated the micro-porous poly-olefin separator, whereby the
electrolyte was in effective contact with both the positive and negative electrodes,
which were nevertheless maintained space and electrically isolated from one another.
[0027] The developed half-cell was discharged (intercalation of lithium-ions) at a constant
current of 2 mA to 0.00 V and then charged (de-intercalation of lithium-ions) at the
same current rate to a cut-off voltage of 1.0 V. The discharge charge process was
repeated several times (usually 2-5) until a fairly constant capacity value of discharge
charge was obtained. Figure 1 shows the discharge charge characteristics of the developed
half-cell containing the mixture of the graphite and molybdenum carbide according
to the present invention. The charge capacity (de-intercalation of lithium ions) of
the cell was 425 mAh/g as shown in Fig. 2, which is considered to be the reversible
capacity of the working electrode (i.e. the electrode containing carbonaceous material
and molybdenum carbide).
[0028] A half-cell was made with the same components as described above except the active
material of the working electrode was S26813 graphite (Superior Graphite Co) without
molybdenum carbide. The half-cell was discharged and charged under the same conditions
as the previous half-cell. Figure 3 shows the discharge charge behavior of this half-cell
containing the electrode material. The charge capacity of the cell was 330 mAh/g as
shown in Fig. 4, which is almost 30% lower than that obtained in accordance with the
present invention.
Example 2
[0029] Several half-cells were made as in Example 1 with as received BG39 graphite (Superior
Graphite Co) and varying amounts of molybdenum carbide (Climax Molybdenum Co.) mixed
with BG39 graphite as working electrodes and metallic lithium counter electrodes and
an electrolyte comprising 1M LiPF
6 in a mixture of ethylene carbonate and diethyl carbonate (2:1 w/w). The half-cells
were first discharged at a constant current to 0.00 V and then charged at the same
current rate to a cut-off voltage of 1.0 V. The discharge charge process was repeated
several times (usually 2-5) until a fairly constant capacity value of discharge charge
was obtained. The charge capacities of these half-cells are shown in Table 1. The
results indicate that the addition of molybdenum carbide increases the charge capacity
of BG39 graphite. Thus, addition of only 5% molybdenum carbide to BG39 graphite increases
its charge capacity from 334 mAh/g to 464 mAh/g.
Table 1: Effect of the Addition of Molybdenum Carbide on Charge Capacity of BG39 Graphite
Amount of Mo2C
(%) |
Charge Capacity
(mAh/g) |
Increase in Capacity
(%) |
0.0 |
334 |
0 |
5.0 |
464 |
39 |
8.0 |
460 |
38 |
15.0 |
391 |
17 |
Example 3
[0030] Two lithium-ion cells designated A1 and A2 were made according to known prior techniques
with LiCoO
2 as cathode material and F399 graphite supplied by Alumina Trading Company, New Jersey
(No molybdenum carbide added) as anode material in 1M LiPF
6 electrolyte in a mixture of EC/DMC solvents (1:1 v/v). Two similar type of lithium-ion
cells designated B 1 and B2 were also built but the F399 graphite anodes of these
cells contained 8% of molybdenum carbide of about 1µm (Climax Molybdenum Co) additive.
The four lithium-ion cells were charged first at 0.5 mA/cm
2 to 4.2 V and then at constant voltage (4.2 V) for 3 hours or until the residual current
dropped to 0.025 mA/cm
2. The cells were then discharged at 0.5 mA/cm
2 to a cut-off voltage of 3.0 V. The cells were charged and discharged for several
times until a fairly constant values of charge and discharge capacities were obtained.
The observed electrochemical performance of the cells is shown in Table 2. Again,
the results demonstrate capacity improvement due to molybdenum carbide additive to
the graphite anodes of cells B1 and B2 as compared with cells A1 and A2 having no
molybdenum carbide additive to graphite anodes.
Table 2: Effects of Molybdenum Carbide Additive to Graphite Anode on Capacity of Lithium-ion
Cell
Cell # |
Molybdenum carbide Additive
(%) |
Cathode Weight
(g) |
Anode Weight
(g) |
Cell Capacity
(mAh) |
Specific Capacity of Anode
(mAh/g) |
A1 |
0 |
0.446 |
0.113 |
35 |
333 |
A2 |
0 |
0.446 |
0.117 |
36 |
331 |
B1 |
8 |
0.446 |
0.115 |
48 |
449 |
B2 |
8 |
0.446 |
0.112 |
47 |
451 |
Example 4
[0031] SFG44 graphite (Timcal Corporation, New Jersey) mixed with 5% molybdenum carbide
(of about 2µm particle size) was used as an anode of a lithium-ion cell to evaluate
the concept of the present invention. The lithium-ion cell included a negative electrode
made from the mixture of SFG44 graphite and 5% molybdenum carbide (about 2 µm), a
lithiated nickel cobalt dioxide positive electrode and 1M LiPF
6 electrolyte in a mixture (1:1 v/v) of ethylene carbonate/dimethyl carbonate (EC/DMC)
solvents. A micro-porous poly-olefin (Celgard 2400) separator was used in between
the positive and negative electrodes to isolate them electronically. The positive
electrode was made from a mixture of 85% LiNi
0.8Co
0.2O
2, 6% carbon black and 9% PVDF in DMF by coating on to an aluminum foil.
[0032] The aprotic, non-aqueous 1M LiPF
6 electrolyte mixture permeated the micro-porous poly-olefin separator, whereby the
electrolyte was in effective contact with both the positive and negative electrodes,
which were nevertheless maintained space and electrically isolated from one another.
[0033] The developed cell was charged at a constant current of 0.5 mA/cm
2 to 4.0 V and then at a constant voltage (4.1 V) for 3 hours or until the current
dropped to 0.02 mA/cm
2. The cell was then discharged at a constant current of 0.5 mA/cm
2 to a cut-off voltage of 2.75 V. The charge discharge process was repeated in order
to evaluate the cycle life. Figure 5 shows the cycling characteristics of the developed
cell according to the present invention. The cell delivered 80 cycles with 93% capacity
retention. The initial anode capacity of the cell was 439 mAh/g and after 80 cycles
the anode capacity was 412 mAh/g.
[0034] A lithium-ion cell was made with the same components as described above except the
negative electrode was made from a mixture of 90% MCMB 2528 carbon and 10% PVDF in
DMF (NO molybdenum carbide) by coating on to a copper foil. It is noteworthy to mention
that MCMB 2528 carbon is used as an active material of anode for commercial lithium-ion
cell. The cell was charged and discharged under the same conditions as the previous
cell. Figure 6 shows the cycling behavior of this cell. The cell lost 9% capacity
after delivering only 80 cycles. The initial anode capacity of the cell was only 327
mAh/g and after 80 cycles, the anode capacity dropped to 296 mAh/g.
[0035] Thus, according to the foregoing description, applicant has provided a concept for
enhancing the reversible capacity of the carbonaceous anode of a lithium ion cell
and/or battery, by combining the carbonaceous material with molybdenum carbide. It
is believed that with the foregoing description in mind, the manner in which various
types of lithium ion cells and/or batteries, with enhanced reversible capacity of
the carbonaceous material(s) of the anode(s) of the cells and/or batteries, will become
apparent to those skilled in the art.
1. A rechargeable electrochemical cell comprising a body of aprotic, non-aqueous electrolyte,
first and second electrodes in effective contact with said electrolyte, the first
electrode comprising a lithiated intercalation compound, and the second electrode
comprising carbonaceous material combined with molybdenum carbide in an amount of
less than 20% (by weight).
2. An electrochemical cell as defined in claim 1, wherein the amount of molybdenum carbide
in the second electrode is in the range of 0. 1% to 15% (by weight).
3. An electrochemical cell as defined in claim 1, wherein the particle size of molybdenum
carbide in the second electrode is in the range of 0.05 µm to 3 µm.
4. An electrochemical cell as defined in claim 1, wherein the lithiated intercalation
compound of the first electrode is selected from the group consisting of LiCoO2, LiNiCoO2, LiNiCoAlO2, LiNiO2, LiMn204, LiMnO2, LiV205, LiV6O13, LiTiS2, Li3FeN2, Li7VN4 and combinations of the foregoing.
5. An electrochemical cell as defined in claim 1, wherein the electrolyte comprises a
lithium compound solute dissolved in a non-aqueous solvent.
6. An electrochemical cell as defined in claim 4, wherein the electrolyte comprises a
solute selected from the group consisting of LiPF6, LiBF4, LiAsF6, LiCF3SO3, LiN (CF3SO2)2, LiCl04, and combinations of the foregoing.
7. An electrochemical cell as defined in claim 5, wherein the electrolyte comprises a
solvent selected from the group consisting of propylene carbonate, ethylene carbonate,
diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, and combinations of
the foregoing.
8. An electrochemical cell as defined in claim 1, wherein the first electrode is a cathode
having a first metal substrate having a high stability in the operating voltage of
the electrochemical cell.
9. An electrochemical cell as defined in claim 8, wherein said first metal substrate
comprises aluminum.
10. An electrochemical cell as defined in claim 8, wherein said second electrode is an
anode having a second metal substrate having a high stability in the operating voltage
of the electrochemical cell.
11. An electrochemical cell as defined in claim 10, wherein said second metal substrate
comprises copper.
12. An electrochemical cell as defined in claim 1, wherein the first electrode is a cathode
that comprises a metal substrate having the lithiated intercalation compound affixed
to a surface thereof, wherein the second electrode is an anode that comprises a second
metal substrate having affixed to a surface thereof the carbon mixed with molybdenum
carbide material thereon, and wherein said respective surfaces of the cathode and
anode are separated from one another by a micro-porous electrically non-conductive
separator that is permeated by said aprotic, non-aqueous electrolyte which is in effective
contact with said respective surfaces of the anode and cathode.
13. An electrochemical cell as defined in claim 12, wherein the metal substrate of the
cathode comprises aluminum and the metal substrate of the anode comprises copper.
14. An electrochemical cell as defined in claim 12, wherein the separator comprises a
micro-porous poly-olefin film.
15. An electrochemical cell as defined in claim 12, wherein the cathode and anode and
their respective substrates and the electrolyte permeated separator are all contained
within a sealed enclosure and wherein means including the respective substrates of
the cathode and anode are provided for connecting said cell to an external electric
circuit.
16. A battery comprising a plurality of electrochemical cells as defined in one of claims
1, 12 and 14, having their respective electrodes connected in an electric circuit
defining a battery of said cells.
1. Aufladbare elektrochemische Zelle, die einen protonenfreien, nicht-wässrigen Elektrolytkörper,
eine erste und eine zweite Elektrode umfasst, die mit dem Elektrolyt in einem wirksamen
Kontakt stehen, wobei die erste Elektrode eine lithiierte Zwischenschichtverbindung
umfasst und die zweite Elektrode ein kohlenstoffhaltiges Material umfasst, das mit
einem Molybdäncarbid in einer Menge von weniger als 20 % (Massenanteil) kombiniert
ist.
2. Elektrochemische Zelle nach Anspruch 1, wobei die Menge des Molybdäncarbids in der
zweiten Elektrode im Bereich von 0,1 % bis 15 % (Massenanteil) liegt.
3. Elektrochemische Zelle nach Anspruch 1, wobei die Partikelgröße des Molybdäncarbids
in der zweiten Elektrode im Bereich von 0,05 µm bis 3 µm liegt.
4. Elektrochemische Zelle nach Anspruch 1, wobei die lithiierte Zwischenschichtverbindung
der ersten Elektrode aus der Gruppe ausgewählt ist, die aus LiCoO2, LiNiCoO2, LiNiCoAl02, LiNiO2, LiMn2O4, LiMnO2, LiV205, LiV6O13, LiTiS2, Li3FeN2, Li7VN4 und Kombinationen der Vorhergehenden besteht.
5. Elektrochemische Zelle nach Anspruch 1, wobei das Elektrolyt einen aufgelösten Lithiumverbindungstoff
umfasst, der in einem nicht-wässrigen Lösungsmittel gelöst ist.
6. Elektrochemische Zelle nach Anspruch 4, wobei das Elektrolyt einen aufgelösten Stoff
umfasst, der aus der Gruppe ausgewählt ist, die aus LiPF6, LiBF4, LiAsF6, LiCF3SO3, LiN (CF3SO2)2, LiCl04, und Kombinationen der Vorhergehenden besteht.
7. Elektrochemische Zelle nach Anspruch 5, wobei das Elektrolyt ein Lösungsmittel umfasst,
das aus der Gruppe ausgewählt ist, die aus Propylencarbonat, Ethylencarbonat, Diethylcarbonat,
Ethylmethylcarbonat, Dimethylcarbonat und Kombinationen der Vorhergehenden besteht.
8. Elektrochemische Zelle nach Anspruch 1, wobei die erste Elektrode eine Kathode mit
einem ersten Metallsubstrat mit einer hohen Stabilität in der Betriebsspannung der
elektrochemischen Zelle ist.
9. Elektrochemische Zelle nach Anspruch 8, wobei das erste Metallsubstrat Aluminium umfasst.
10. Elektrochemische Zelle nach Anspruch 8, wobei die zweite Elektrode eine Anode mit
einem zweiten Metallsubstrat mit einer hohen Stabilität in der Betriebsspannung der
elektrochemischen Zelle ist.
11. Elektrochemische Zelle nach Anspruch 10, wobei das zweite Metallsubstrat Kupfer umfasst.
12. Elektrochemische Zelle nach Anspruch 1, wobei die erste Elektrode eine Kathode ist,
die ein Metallsubstrat umfasst, wobei die lithiierte Zwischenschichtverbindung an
eine Oberfläche davon angebracht ist, und die zweite Elektrode eine Anode ist, die
ein zweites Metallsubstrat umfasst, wobei an eine Oberfläche davon der Kohlenstoff
angebracht ist, der darauf mit dem Molybdäncarbidmaterial gemischt ist, und wobei
die entsprechenden Oberflächen der Kathode und der Anode voneinander durch einen mikroporösen
elektrisch nicht-leitenden Separator getrennt sind, der von dem protonenfreien nicht-wässrigen
Elektrolyt durchdrungen ist, das mit den entsprechenden Oberflächen der Anode und
der Kathode im wirksamen Kontakt steht.
13. Elektrochemische Zelle nach Anspruch 12, wobei das Metallsubstrat der Kathode Aluminium
umfasst und das Metallsubstrat der Anode Kupfer umfasst.
14. Elektrochemische Zelle nach Anspruch 12, wobei der Separator eine mikroporöse Polyolefinschicht
umfasst.
15. Elektrochemische Zelle nach Anspruch 12, wobei die Kathode und die Anode und ihre
entsprechenden Substrate und der von Elektrolyt durchdrungene Separator alle innerhalb
einer versiegelten Umhüllung aufgenommen sind und wobei Mittel, die die entsprechenden
Substrate der Kathode und der Anode aufweisen, zum Verbinden der Zelle mit einer externen
elektrischen Schaltung bereitgestellt sind.
16. Batterie, die eine Vielzahl von elektrochemischen Zellen nach einem der Ansprüche
1, 12 und 14 umfasst, wobei ihre entsprechenden Elektroden in einer elektrischen Schaltung
verbunden sind, die eine Batterie dieser Zellen definiert.
1. Cellule électrochimique rechargeable comportant un corps d'électrolyte non aqueux,
aprotique, des première et seconde électrodes en contact effectif avec ledit électrolyte,
la première électrode comportant un composé d'intercalation lithié, et la seconde
électrode comportant une matière carbonée combinée avec du carbure de molybdène dans
une quantité inférieure à 20 % (en poids).
2. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle la
quantité de carbure de molybdène dans la seconde électrode est dans la gamme de 0,1
% à 15 % (en poids).
3. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle la
taille de particule du carbure de molybdène dans la seconde électrode est dans la
gamme de 0,05 µm à 3 µm.
4. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle le
composé d'intercalation lithié de la première électrode est choisi dans le groupe
constitué de LiCoO2, LiNiCoO2, LiNiCoAlO2, LiNiO2, LiMn2O4, LiMnO2, LiV2O5, LiV6O13, LiTiS2, Li3FeN2, Li7VN4 et de combinaisons de ce qui précède.
5. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle l'électrolyte
comporte un soluté de composé de lithium dissous dans un solvant non aqueux.
6. Cellule électrochimique telle que définie dans la revendication 4, dans laquelle l'électrolyte
comporte un soluté choisi dans le groupe constitué de LiPF6, LiBF4, LiAsF6, LiCF3SO3, LiN(CF3SO2)2, LiClO4, et leurs combinaisons.
7. Cellule électrochimique telle que définie dans la revendication 5, dans laquelle l'électrolyte
comporte un solvant choisi dans le groupe constitué de carbonate de propylène, de
carbonate d'éthylène, de carbonate de diéthyle, de carbonate d'éthylméthyle, de carbonate
de diméthyle, et de leurs combinaisons.
8. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle la
première électrode est une cathode ayant un premier substrat de métal ayant une stabilité
élevée dans la tension de fonctionnement de la cellule électrochimique.
9. Cellule électrochimique telle que définie dans la revendication 8, dans laquelle ledit
premier substrat de métal comporte de l'aluminium.
10. Cellule électrochimique telle que définie dans la revendication 8, dans laquelle ladite
seconde électrode est une anode ayant un second substrat de métal ayant une stabilité
élevée dans la tension de fonctionnement de la cellule électrochimique.
11. Cellule électrochimique telle que définie dans la revendication 10, dans laquelle
ledit second substrat de métal comporte du cuivre.
12. Cellule électrochimique telle que définie dans la revendication 1, dans laquelle la
première électrode est une cathode qui comporte un substrat de métal ayant le composé
d'intercalation lithié fixé sur une surface de celui-ci, dans laquelle la seconde
électrode est une anode qui comporte un second substrat de métal ayant, fixé sur une
surface de celui-ci, le carbone mélangé avec du carbure de molybdène sur celui-ci,
et dans laquelle lesdites surfaces respectives de la cathode et de l'anode sont séparées
l'une de l'autre par un séparateur microporeux, électriquement non conducteur qui
est infiltré par ledit électrolyte non aqueux, aprotique qui est en contact effectif
avec lesdites surfaces respectives de l'anode et de la cathode.
13. Cellule électrochimique telle que définie dans la revendication 12, dans laquelle
le substrat de métal de la cathode comporte de l'aluminium et le substrat de métal
de l'anode comporte du cuivre.
14. Cellule électrochimique telle que définie dans la revendication 12, dans laquelle
le séparateur comporte un film de polyoléfine microporeux.
15. Cellule électrochimique telle que définie dans la revendication 12, dans laquelle
la cathode et l'anode et leurs substrats respectifs et le séparateur infiltré par
l'électrolyte sont tous contenus à l'intérieur d'une enceinte scellée, et dans laquelle
des moyens incluant les substrats respectifs de la cathode et de l'anode permettent
de relier ladite cellule à un circuit électrique externe.
16. Batterie comportant une pluralité de cellules électrochimiques telles que définies
dans l'une des revendications 1, 12 et 14, ayant leurs électrodes respectives reliées
dans un circuit électrique définissant une batterie desdites cellules.