JP2002270162A - Electrochemical cell constituted by alkaline metal battery or ion electrochemical battery containing double current collecting body cathode structure with usage of two kinds of active material mixtures - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery exhibiting enhanced rate capacity and energy density. SOLUTION: A first cathode structure produced by a first cathode active material exhibiting low energy density and high rate capacity such as vanadium oxide silver (SVO) and a second cathode active material having high energy density and low rate capacity such as CFx are mixed in order to produce a cathode having a smaller ratio of SVO than CFx and fastened between two current collecting bodies. The second cathode mixture comprising the SVO active material and the CFx active material contacts with an outer surface of the current collecting body. The ratio of the SVO to the CFx of the second structure is larger than the first structure. An example of the cathode is as follows: (100-y)%SVO+y%CFx , 0<=y<=100/current collecting body/(100-x)% SVO+x%CFx , 0<=x<=100/current collecting body/(100-y)%SVO+y%CFx , 0<=y<=100 The ratio of x to y is selected from the group consisting of y<x, x<y, and x=y).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the conversion of chemical energy into electrical energy. In particular, the present invention relates to a novel sandwich cathode structure having two types of cathode active materials consisting of two different mixtures. The first cathode active material is a material having a relatively low energy density but a relatively high rate capability, while the second cathode active material is a material having a relatively high energy density but a relatively low rate capability. . The cathode has a sandwich structure in which the first cathode structure is sandwiched between two current collectors. The second cathode structure contacts at least the other side of one of the current collectors,
Preferably it faces the anode. In each of the first and second cathode structures, the weight percentage of the first and second active materials is 100. For example, the weight percentage of the first cathode structure is (100−y)% of the first cathode active material + y% of the second cathode active material, where y is 0 ≦ y.
≦ 100, and the weight percentage of the second cathode structure is (100−x)% of the first cathode active material + x% of the second cathode active material, where x is 0 ≦ x ≦ 100,
Further, the relation between x and y is x <y, y <x or x = y
It is.

The cathode configuration of the present invention is relatively safe even in a short circuit condition and is useful in applications requiring high energy densities, such as power supplies associated with implantable medical devices.

[0003]

2. Description of the Related Art The capacity of an electrochemical cell depends not only on the assembly design and mounting efficiency of electrodes, but also on the type of active material used. For example, in the case of a lithium battery, silver vanadium oxide (SVO 4), particularly ε-phase silver vanadium oxide (Ag
It is generally known that V ₂ O _5.5 ) is desirable as a cathode active material. The theoretical volume of this active material is 1.37
An Ah / ml, CF when _x theoretical volume of material (x = 1.1) is compared as a 2.42 Ah / ml, than the ε-phase silver vanadium oxide towards the CF _x material, 1.77 volumes Will be larger.

[0004] By combining the rate high cathode material with high capacity material such as SVO such CF _x, is an attempt to use as a material for high capacity, U.S. Patent No. 5,
As reported by Weiss et al. In 180,642, electrochemical cells made from such cathode compounds have a lower rate capability. CF
Even though the theoretical capacity of the battery is increased by using x as part of the cathode mixture, the capacity is partially reduced in high rate discharge applications due to its reduced power capability.

No. 5,614,331 to Takeuchi et al., Assigned to the assignee of the present invention, discloses a medium rate CFx cell for powering the circuitry of an implantable defibrillator. SV that simultaneously supplies power to high-rate applications
O Describes how to use batteries. The advantage of this method is that all of the high power SVO energy is reserved for power demanding applications such as charging capacitors, and for functional monitoring devices that generally have low power demands such as monitoring heart rate, for example. Power can be supplied by a high capacity CFx system. However, this battery structure requires very careful design to balance the capacity of both high-power (SVO) and low-power (CFx) batteries to reach their lifetimes at or near the same time. Can be Such a balance is nonetheless difficult to achieve due to the requirements of various devices for use in a particular patient.

[0006]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a new concept in electrode design to improve the performance of lithium electrochemical cells. This new electrode configuration is particularly useful where increased energy density is desired for applications that provide relatively high safety under short circuit conditions. In addition, since the life of the battery is predictable, it is useful for battery replacement in applications such as medical devices that can be implanted in the body.

[0007]

SUMMARY OF THE INVENTION To meet these needs, a new sandwich cathode design comprises a first cathode active material having a relatively low energy density but a relatively high rate capability, such as SVO. And a second cathode structure composed of a second cathode active material having a relatively high energy density but a relatively low rate capability, such as CFx, for example. It is provided by being sandwiched between the bodies, wherein the SVO is mixed in a smaller proportion than CFx. The second cathode mixture composed of the SVO active material and the CFx active material is in contact with the outside of the current collector, but the ratio of SVO to CFx is larger in the second structure than in the first structure. . Such an exemplary cathode design
(100−y)% SVO + y% CFx, 0% by weight
≦ y ≦ 100 / current collector / (100 −x) SVO% + x% CFx, 0
≦ x ≦ 100 / current collector / (100−y)% SVO + y% CFx, 0
≦ y ≦ 100 and may be x <y, y <x or x = y.

[0008] These and other objects of the present invention will become apparent with reference to the following description.

[0009]

DETAILED DESCRIPTION OF THE INVENTION An electrochemical cell according to the present invention comprises:
It consists of an anode made of a metal selected from the IA, IIA and IIIB groups of the Periodic Table of Elements. Such anode active materials include lithium, sodium, potassium and the like, alloys thereof, and, for example, Li-Si, Li-Al, Li-B, Li-Mg, and Li-Si.
-B Intermetallic compounds including alloys and their intermetallic compounds are used. A preferred anode comprises lithium. Another anode is composed of a lithium alloy, such as a lithium-aluminum alloy. The higher the weight ratio of aluminum in the alloy, the lower the energy density of the battery.

[0010] The anode may take various forms, but is preferably a thin metal plate or foil of anode metal pressed or rolled on a metal anode current collector, and preferably the anode component is It is composed of titanium, titanium alloy or nickel. Copper, tungsten and tantalum are also suitable as metals for the anode current collector. In the exemplary battery of the invention, the anode component has an extended tab or lead of the same metal as the anode current collector, i.e., preferably made of nickel or titanium, which is integrally formed therewith, such as by welding, and The case negative electrical configuration is connected to a battery case made of conductive metal by welding. The anode can also have a low surface cell design, such as other geometries, such as bobbins, cylinders or pellets.

The electrochemical cell according to the present invention further comprises:
It has a cathode made of an electrically conductive metal and serves as the other electrode of the battery. The cathode is preferably made of a solid material, and the electrochemical reaction moves ions from the anode to the cathode in atomic or molecular form. The solid (solid layer) cathode is composed of a first active material having a carbonaceous chemical property and a second active material comprising a metal element, a metal oxide, a mixed metal oxide, a metal sulfide and a combination thereof. The metal oxide, mixed metal oxide, and metal sulfide of the second active material have a relatively lower energy density and a relatively higher rate capability than the carbon-based first active material.

In this regard, the first active material has a relatively high energy density and a relatively low rate capability as compared with the second cathode active material. The first active material is preferably a carbon-based compound prepared from carbon and fluorine, including carbon-based graphite and non-graphite species such as coke, charcoal, and activated carbon.
Fluorocarbon is represented by (CFx) n, where x is about 0.1
１1.9, preferably between about 0.5 and 1.2, and for (C ₂ F) n, n is the number of monomer units that can vary widely.

[0013] The sandwich cathode design according to the present invention preferably comprises a chemical addition, a reaction or various other metal oxides, metal sulfides during heat treatment in mixed state, during sol-gel formation, during chemical vapor deposition or during hydrothermal synthesis. And / or a second formed by a contact reaction of a metal element or the like.
Contains active material. The resulting active materials include metals, oxides and sulfides of the IB, IIB, IIB, IVB, VB, VIB, VIIB and VIII groups, including noble metals and / or other oxidized and sulfided compounds. Kinds are included. The preferred second cathode active material is at least a reaction product of silver and vanadium.

One of the preferred mixed metal oxides is
Wherein the general formula is SM _x V ₂ O _y , wherein SM in the general formula is a metal selected from groups IB to VIIB and VIII of the periodic table of elements, x is about 0.3 to 2.0, Transition metal oxides wherein y is about 4.5-6.0. Without limitation, as one illustrative cathode active material, the general formula in any one of its many phases may be Ag _x V ₂ O _y silver vanadium oxide, i.e., x in the general formula 0.35, y is 5.8, β-phase silver vanadium oxide, x in the general formula is 0.80, y is 5.40, γ phase-vanadium oxide, and x is 1.0 in the general formula. There may be mentioned the epsilon phase-silver vanadium oxide with y = 5.5 and cathode active materials composed of combinations and mixtures of the phases. For more information on such cathode active materials, see U.S. Pat. No. 4,477,898 to Liang et al., Assigned to the assignee of the present invention.
No. 310,609.

Another preferred composite transition metal oxide cathode material is Cu _x Ag _y V ₂ O _z (CSVO), which is a combination of V ₂ O _z (z ≦ 5), Ag ₂ O and CuO. Wherein Ag ₂ O has any of silver (II), silver (I) or silver (0) in an oxidized state,
CuO is either oxidized copper (II), copper (I) or copper (0). Composite cathode active material thus a metal oxide - metal oxides - metal oxide, metal - metal oxide - metal oxide or metal - metal - what is known as a metal oxide, the Cu _x Ag _y V ₂ The range of the material composition of O _z is about 0,0.
01 ≦ z ≦ 6.5 is preferred. Typical shape of CSVO is Cu _0.16
Ag _0.67 V ₂ O _{z (z} is about 5.5) _{and, Cu 0.5 Ag 0 .5 V 2} O z (z
Is 5.75). Regarding the oxygen content, the theoretical ratio of oxygen in CSVO depends on whether the cathode material is prepared in an oxidizing atmosphere such as air or oxygen, or in an inert atmosphere such as argon, nitrogen or helium. Since it changes, it is specified by z. For details of this cathode active material, see U.S. Pat.
No. 5,472,810 and U.S. Pat.
No. 340. These two patents are assigned to the assignee of the present invention.

In a broader sense, the first active material in a sandwich cathode design within the scope of the present invention may be any material having a relatively higher energy density and a lower rate capability than the second active material. In addition to fluorocarbon, Ag ₂ O, Ag ₂ O ₂ , CuF ₂ , Ag ₂ CrO ₄ , MnO _2, and SVO itself are also useful as the first active material, in addition to silver vanadium oxide and copper copper vanadium oxide. V ₂ O ₅ , MnO ₂ , LiCo
O ₂ , LiNiO ₂ , LiMn ₂ O ₄ , TiS ₂ , Cu ₂ S, FeS, FeS ₂ , copper oxide, copper vanadium oxide and mixtures thereof are useful as the second active material. In a broader sense, either one of the first and second cathode structures is a mixture of two or three or more of the above active materials, or one of the cathode structures is a single active material, The other may contain two or more of the above active materials.

Table 1 shows the true densities and theoretical volumes (capacities) of some active materials.・ Table 1 Substance True density (g / ml) Theoretical capacity (Ah / ml) CF _x 2.70 2.42 Ag ₂ O ₂ 7.48 3.24 Ag ₂ O 7.14 1.65 AgV ₂ O _5.5 4.34 1.37

According to the data shown in Table 1, CF _x , Ag ₂ O ₂ , Ag ₂ O
Are shown to have higher theoretical volumes than SVO. Further, each of the silver-containing substances listed in Table 1 is pressed into an adhesive pellet that can be easily bonded to a current collector without adding a binder or a conductive additive. This means that these silver-containing materials are useful as second active materials in sandwich cathode designs according to the present invention. In fact, it is very difficult to press the electrode material to its true density,
The actual theoretical capacity is smaller than the capacity listed in Table 1.
Table 2 shows a substantial density and a substantial capacity based on the experimental results of the above-mentioned cathode material.

Table 2 Substance Actual density (g / ml) Theoretical true density Actual volume (Ah / ml)% with respect to AgV ₂ O _5.5 (94%) 3.40 * 78.3 1.07 AgV ₂ O _5.5 (100%) 4.10 94.5 1.29 CF _x (91%) 1.41 * 52.2 1.27 Ag ₂ O (100%) 6.57 92.0 1.52 Ag ₂ O ₂ (100%) 6.01 80.3 2.62 * indicates the actual density of the active material, non- Active substance

According to the data in Table 2, in the case of the silver oxide material,
Similar discharge capacity than the volume of CF _x and SVO material that has been shown is large. For 100% SVO, SVO is 94%,
21% larger in volume than the cathode electrode with 3% PTFE binder and 3% conductive diluent. The capacity data listed in Table 2 is a theoretical value after completely reducing each material.

Prior to making a sandwich electrode for incorporation in an electrochemical cell according to the present invention, the first and second cathode active materials prepared as described above are preferably made of a more active material such as a powdered fluoropolymer. Preferably, it is mixed with a binder material, such as powdered polytetrafluoroethylene or powdered polyvinylidene fluoride, in a ratio of about 1: 5 by weight percentage of the cathode mixture. In addition, to improve conductivity, about 10% by weight
Is added to the cathode mixture. Suitable materials for this purpose include acetylene black, carbon black and / or graphite or metal powders such as powdered nickel or aluminum, powdered titanium and powdered stainless steel. Thus, a preferred cathode active material would contain about 3% by weight powdered fluoropolymer binder, about 3% by weight conductive diluent, and about 94% cathode active material.

Cathode components for incorporation in an electrochemical cell according to the present invention include stainless steel, titanium, tantalum, platinum, gold, aluminum,
First and second cathode active materials in a suitable current collector selected from the group consisting of a cobalt-nickel alloy, a high-alloy ferritic stainless steel containing molybdenum and chromium, and an alloy containing nickel, chromium, and molybdenum. Is produced by rolling, stretching or pressing. The preferred current collector material is titanium, and the most preferred titanium cathode current collector has a thin layer formed with a graphite / carbon paint applied to it. Cathodes made as described above may have one or more plates of anode material functionally associated with one or more plate types, or articles corresponding to anode materials with structures such as "jelly rolls". The strip can be in the form of a wound strip.

According to the present invention, a CFx cathode material providing a relatively low power or rate capability and a relatively high energy density or volume capacity, and an SVO cathode having a relatively low energy density and a relatively high rate capability, In two different mixtures, both materials are mounted on opposite sides of the current collector so that they are in direct contact with each other. Thus, the first cathode structure of the exemplary cathode plate is short-circuited by weight with the second cathode structure having the following configuration. The first cathode structure is composed of a first percentage of (100-x)% of the first cathode active material and a second percentage of x% of the second cathode active material, and the second cathode structure is , A third percentage (100-y)% of the first cathode active material, and a fourth percentage y% of the second cathode active material. The ratio between x and y in the first and second cathode structures is either x <y, y <x or x = y.

An exemplary illustrative cathode configuration, in weight percent, is as follows. (100-y)%
First cathode active material + y% Second cathode active material, 0 ≦ y
≤100 / current collector / (100-x)% first cathode active material + x
% Second cathode active material, 0 ≦ x ≦ 100 / current collector / (100−
y)% first cathode active material + y% second cathode active material,
0 ≦ y ≦ 100. x <y, y <x or x = y.

Another illustrative cathode configuration, in weight percent, is as follows. (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / current collector / (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / (10
0−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / current collector / (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100. In the above, x <y, y <x or x = y. Or (10
0−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / first current collector / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / second current collector / (100−z)% first cathode active material + z% second cathode active material, 0 ≦ z ≦ 100. In the above, y ≦ x and z ≦ x, and y <z or y> z. Or (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / first current collector / (100−y)%
First cathode active material + y% Second cathode active material, 0 ≦ y
≦ 100 / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / (100−z)% first cathode active material + z% second cathode active material, 0 ≦ z ≤100 / second
Current collector / (100−z)% first cathode active material + z% second
Cathode active material, 0 ≦ z ≦ 100. In the above, y ≤ x and
z ≦ x, and y <z or y> z.

A further illustrative cathode configuration is as follows, in weight percentages: (100−y)% first cathode active material + y% second cathode active material / current collector /
(100−x)% first cathode active material + x% second cathode active material. In the above, x <y, y <x or x = y.

Further, the following cathode structure may be employed in terms of weight ratio. (100−y)% SVO + y% CFx, 0 ≦ y ≦
100 / current collector / (100−x)% SVO + x% CFx, 0 ≦ x ≦ 1
00 / current collector / (100−y)% SVO + y% CFx, 0 ≦ y ≦ 1
00. In the above, y <x, x <y or x = y. Also, (100−y)% SVO + y% CFx, 0 ≦ y ≦ 100 / current collector / (100−y)% SVO + y% CFx, 0 ≦ y ≦ 100 / (100
−x)% SVO + x% CFx, 0 ≦ x ≦ 100 / (100−y)%
SVO + y% CFx, 0 ≦ y ≦ 100 / current collector / (100−y)%
SVO + y% CFx, 0 ≦ y ≦ 100. In the above, y <x, x <y
Or x = y.

A preferred electrochemical cell has a lithium anode and the cathode has the following composition in weight percentages: (100-y)% SVO + y
% CFx / current collector / (100−x)% SVO + x% CFx. In the above, y ≦ x for (100−y)% SVO + y% CFx, with the cathode facing the lithium anode.

In another preferred electrochemical cell,
While having an anode made of lithium, the cathode has the following composition in weight percentage. (100-y)% SV
O + y% CFx / current collector / (100-x)% SVO + x% CFx.
In the above, x ≦ y for (100−y)% SVO + y% CFx
Where the cathode faces the lithium anode.

Since the volume of CFx is much larger than the volume of the SVO material, almost 1.77 times the volume, it is technically practical to optimize the final battery capacity, It is advisable to maximize the amount of CFx material and to minimize the amount of SVO material used, to the extent acceptable in terms of performance.

Further, the display of the expired battery life is the same as that of a standard Li / SVO battery. Also according to the invention
SVO electrode material and CFx electrode material have the same life.
This is irrelevant to the use of the battery and there is no waste of energy capacity as both electrode materials end their life at the same time.

To avoid an internal short circuit condition, the sandwich cathode is separated from the anode of the IA, IIA or IIB group by a suitable separator material. The separator is made of an electrically insulating material, the material of which is chemically inert with the anode active material and the cathode active material, both of which are chemically inert to the electrolyte and insoluble in the electrolyte. It is. Further, the material of the separator has sufficient porosity to generate flow through the electrolyte during the electrochemical reaction of the battery. Illustrative separator materials are used alone or woven from fluoropolymeric fibers, including polyvinylidene fluoride, polyethylene tetrafluoroethylene, and polyethylene chlorotrifluoroethylene, laminated with a fluoropolymeric microporous film. Fibers, non-woven glass, polypropylene, polyethylene, glass fiber materials, ceramics, ZITEX (Chemplast In
c.) A commercially available polytetrafluoroethylene membrane under the name CELGARD (Celanese Plastic Company, Inc.)
Polypropylene membrane and DEXI marketed under the name
A thin film commercially available under the name of GLAS (CH Dexter, Div., Dexter Corp.) is used.

The electrochemical cell according to the present invention further includes a non-aqueous ion conductive electrolyte which acts as a medium for ion transfer between the anode and cathode electrodes during the electrochemical reaction of the cell. Electrochemical reactions at the electrodes involve the conversion of atoms or molecular ions that move from the anode to the cathode. Thus, non-aqueous electrolytes suitable for the present invention are substantially inert to the anode and cathode materials,
It exhibits the physical properties required for ion migration, ie, low surface tension and low wettability.

The suitable electrolyte includes an inorganic ion conductive salt dissolved in a non-aqueous solvent, and more preferably, the electrolyte includes a non-aqueous solvent composed of a low viscosity solvent and a high dielectric constant solvent. Includes ionized alkali metal salts that dissolve in the protic organic solvent mixture. The inorganic ion conductive salt is
It functions to promote the reaction or transfer of anode ions to the cathode active material. The ion forming the alkali metal salt is preferably an ion similar to the alkali metal forming the anode.

In the case of an anode composed of lithium,
The alkali metal salt of the electrolyte is a salt based on lithium. The beneficial known lithium salt solvent for transport of alkali metal ions from the anode to the _{cathode, LiPF 6, LiBF 4, LiAsF} 6, LiSbF 6, LiClO 4, LiO 2,
LiAlCl ₄ , LiGaCl ₄ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , Li
SCN, LiO ₃ SCF ₃ , LiC ₆ F ₅ SO ₃ , LiO ₂ CCF ₃ , LiSO ₆ F, LiB
(C ₆ H ₅ ) ₄ , LiCF ₃ SO ₃ and mixtures thereof.

Low viscosity solvents useful in the present invention include
Linear and cyclic et
hers), and tetrahydrofuran (THF) and methyl alcohol
Acetate (MA), diglyme, triglyme
(Triglyme), tetraglyme, dimethyl
Carbonate (DMC), 1,2-dimethoxyethane (DME
 ), 1,2-diethoxyethane (DEE), 1-ethoxy,
2-methoxyethane (EME), ethyl methyl carbonate
G, methyl propyl carbonate, ethyl propyl carbonate
Carbonate, diethyl carbonate, dipropyl carbonate
High dielectric constant solvents include
Lipylene carbonate (PC), ethylene carbonate
(EC), butylene carbonate, acetonitrile, dime
Tylsulfoxide, dimethylformamide, dimethyl
Acetamide, γ-valerolactone, γ-butyrolact
(GBL), N-methyl-pyrrolidinone (NMP) and
Cyclic carbonates, cyclic esters, rings such as mixtures thereof
Amides. In the present invention, preferred ano
The mode is lithium metal and the preferred electrolyte is a high dielectric
Propylene carbonate as a solvent and a low-viscosity solvent
1,2-dimethoxyethane at a volume ratio of 50:50
0.8M to 1.5M LiAsF₆Or LiPF ₆ 
Is dissolved.

The battery assembly described herein is preferably formed in a wound element configuration. That is, the negative electrode, anode, and separator that are made together have an anode on the outside of the roll, either in a “jellyroll” type configuration or to make electrical contact with a battery case in a case-negative configuration. Are arranged in a "wound element cell stack" system. By using appropriate upper and lower insulators, the wound cell stack is placed in a suitably dimensioned metal case. This metal case can be made of materials such as stainless steel, mild steel, nickel plated mild steel, titanium, tantalum or aluminum,
However, the present invention is not limited to these as long as the metal material has compatibility with other battery components.

The battery header is composed of a metal disk-shaped body, the first hole of which is a glass-to-metal seal / terminal pin feedthrough.
The second hole is for electrolyte filling. The glass used is CABAL12, TA23,
It is a corrosion-resistant type containing about 50% by weight of silicon such as FUSITE425 or FUSITE435. The anode terminal pin feedthrough is preferably composed of titanium, but molybdenum, aluminum, nickel alloy or stainless steel can also be used. Battery headers are typically made from materials similar to the material of the case, and the anode terminal pins supported in the seal between glass and metal are:
Next, it is supported by a header welded to the case containing the electrode assembly. The battery is then filled with the electrolyte solution described above and hermetically sealed, such as by tightly welding a stainless steel ball over the fill hole. However, there is no particular limitation to this method.

It should be noted that the exemplary electrochemical system according to the present invention can also be constructed in a case-anode configuration.

As described in detail above, the battery of the present invention can be used for cardiac defibrillators, cardiac pacemakers, and nerve stimulators.
It is particularly useful for powering implantable medical devices such as imulators and drug pumps. As will be appreciated by those skilled in the art, implantable cardiac defibrillators require a stable, constant load power supply to energize circuitry that controls, for example, electrocardiographic sensing and pacing functions. Also, for monitoring the function of this medical device, a current of about 1 microamp to about 100 milliamps is required. Occasionally, in the case of a defibrillator, it is required to deliver an electric shock to the heart, for example, to treat arrhythmias that can be fatal if left uncorrected. This requires a high rate pulse discharge load component during capacitor charging in the defibrillator. Operation of this medical device requires a current of about 1 amp to about 4 amps.

As used herein, "pulse" means a short-term shock wave of a current having a much greater amplitude than the pre-pulse current just before the pulse. The pulse train is composed of at least two current pulses and is a relatively short continuous pulse, regardless of whether there is an open pause between the pulses.

In that regard, an important problem of the present invention is that while the medical device is monitoring its function, that is, during discharge at an intermediate rate, the first and second cathode structures are not connected to the first and second cathode structures. The cathode active materials are in equilibrium because they are both discharging at about the same rate or share an equal current load. However, when the medical device is performing the foregoing operations, i.e., emitting pulses at a high rate, only the first cathode active material, e.g., SVO, in the first and second cathode structures is discharged. Therefore, when the battery returns to the function monitoring operation of the medical device, the CFx as the second cathode active material plays a role of recharging the energy loss consumed during the operation of the medical device to the SVO material again. Fulfill. This charging is continued until the first and second cathode active materials are at equilibrium voltage, so that at relatively high discharges above the current discharge required by the device to monitor function, the battery is discharged. The first and second cathode structures, which have a disproportionate proportion of the first and second cathode active materials when discharged over a long period of time, can be used until the CFx material is reduced to a current load capable of recharging the SVO material. It remains unbalanced.

Various modifications to the inventive concept described herein will be apparent to those skilled in the art, in a proper understanding thereof, without departing from the spirit and scope of the invention as defined by the appended claims.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Esther S., Takeuchi 14051, New York, United States, East Amherst, St. Raphael Court 38 F-term (reference) 5H017 AA03 AS02 DD05 EE01 EE04 EE05 5H024 AA02 AA03 AA04 AA06 AA07 AA12 CC07 CC16 DD15 EE01 FF15 FF16 FF17 FF18 FF20 FF31 HH01 HH04 HH15 5H050 AA02 AA08 BA16 CA02 CA05 CA08 CA09 CA11 CB12 DA02 DA04 DA06 DA08 FA02 FA05 GA22 HA00 HA01 HA07 HA17

Claims (53)

[Claims] 1. An electrochemical cell comprising: a) an anode; b) a first cathode structure shorted by a second cathode structure; c) an electrolyte for activating these anodes and cathodes. The first cathode structure may include a weight ratio of (100−x)% (first percentage) of the first cathode active material and x% (second percentage) of the second cathode active material. The cathode structure comprises (100-y)% (third percentage) of the first cathode active material and y% (fourth percentage) of the second cathode active material.
The first cathode active material is different from the second cathode active material, and the energy density (first energy density) of the first cathode active material is the second energy density;
The rate capacity (first rate capacity) of the first cathode active material was smaller than the energy density (second rate capacity) of the cathode active material, and was larger than the rate capacity (second rate capacity) of the second cathode active material. An electrochemical cell, characterized by: 2. The electrochemical cell according to claim 1, wherein the anode is made of an alkali metal. 3. The method of claim 1, wherein the first and second cathode structures are
The electrochemical cell according to claim 1, wherein the ratio of x and y is selected from the group consisting of x <y, y <x and x = y. 4. The method according to claim 1, wherein the first and second cathode active materials are SVO.
, CSVO, V ₂ O ₅ , MnO ₂ , LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Cu
O ₂ , TiS ₂ , Cu ₂ S, FeS, FeS ₂ , CF _x , Ag ₂ O, Ag ₂ O ₂ , Cu
_{F, Ag 2 CrO 4, MnO} 2, copper oxide electrochemical cell according to claim 1, characterized in that it is selected from the group consisting of copper vanadium oxide, and mixtures thereof. 5. The structure of the cathode is such that the weight ratio is (100−y
)% First cathode active material + y% second cathode active material, 0
≦ y ≦ 100 / current collector / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / current collector /
(100−y)% first cathode active material + y% second cathode active material, and 0 ≦ y ≦ 100, and the ratio of x and y is x <
2. The electrochemical cell according to claim 1, wherein the cell is selected from the group consisting of y, y <x and x = y. 6. The structure of the cathode is (100−y
)% First cathode active material + y% second cathode active material, 0
≦ y ≦ 100 / current collector / (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / (100−
x)% first cathode active material + x% second cathode active material,
0 ≦ x ≦ 100 / (100−y)% first cathode active material + y
% Second cathode active material, 0 ≦ y ≦ 100 / current collector / (100−
y)% first cathode active material + y% second cathode active material, and 0 ≤ y ≤ 100 and the ratio of x to y is x <y, y
2. The electrochemical cell according to claim 1, wherein the cell is selected from the group consisting of <x and x = y. 7. The structure of the cathode is such that the weight ratio is (100−y
)% First cathode active material + y% second cathode active material /
Current collector / (100−x)% first cathode active material + x% second
A cathode active material wherein the ratio of x and y is x <y, y <
The electrochemical cell according to claim 1, wherein the electrochemical cell is selected from the group consisting of x and x = y. 8. The structure of the cathode is such that the weight ratio is (100−y
_{)% SVO + y% CF x} , 0 ≦ y ≦ 100 / current collector / (100 -x
_{)% SVO + x% CF x} 0 ≦ x ≦ 100 / current collector / (100 -y
) _{A% SVO + y% CF x,} 0 ≦ y ≦ 100, x and y
Is selected from the group consisting of: x <y, y <x, and x = y. 9. The structure of the cathode is (100−y
_{)% SVO + y% CF x} , 0 ≦ y ≦ 100 / current collector / (100 -y
)% SVO + y% CFx, 0 ≦ y ≦ 100 / (100−x)% SV
O + x% CFx, 0 ≦ x ≦ 100 / (100−y)% SVO + y%
CFx, 0 ≦ y ≦ 100 / current collector / (100−y)% SVO + y%
CF _x , 0 ≦ y ≦ 100, the ratio of x and y is x <y,
2. The electrochemical cell according to claim 1, wherein the electrochemical cell is selected from the group consisting of y <x and x = y. 10. The anode is lithium, and the weight ratio of the cathode is (100−y)% SVO + y% CF _x / current collector / (100−x)% SVO + x% CFx, y <x. in Te and (100 -y)% SVO + y % CF x, electrochemical cell of claim 1 in which the cathode is characterized in that facing the lithium anode. 11. The anode is lithium, and the weight composition ratio of the cathode is (100−y)% SVO + y% CF _x / current collector / (100−x)% SVO + x% CFx, x <y. in Te and (100 -y)% SVO + y % CF x, electrochemical cell of claim 1 in which the cathode is characterized in that facing the lithium anode. 12. A cathode comprising: a) an anode; and b) a first cathode structure sandwiched between first and second current collectors, wherein the second cathode structure is connected to the first cathode structure. The first cathode structure is in contact with at least one of the opposing current collectors, and the (100-x)
% Of the first cathode active material and x% of the second cathode active material, and the second cathode structure is composed of (100-y)% of the first cathode active material and y% of the second cathode active material. The first cathode active material is different from the second cathode active material, the first cathode active material has a first energy density and a first rate capability, and the second cathode active material has a second energy density and a second energy density. A cathode having a dual rate capability, wherein the first energy density of the first cathode active material is less than the second energy density and the first rate capability is greater than the second rate capability of the second cathode active material; c) an anode; An electrochemical cell comprising an electrolyte for activating a cathode. 13. The electrochemical cell according to claim 12, wherein the anode is made of an alkali metal and the electrolyte is non-aqueous. 14. The method of claim 1, wherein the ratio of x and y in the first and second cathode structures is selected from the group consisting of x <y, y <x and x = y.
3. The electrochemical cell according to 2. 15. The structure of the cathode is as follows:
y)% first cathode active material + y% second cathode active material,
0 ≦ y ≦ 100 / first current collector / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / second current collector / (100−y)% 1 cathode active material + y% a second cathode active material, wherein 0 ≦ y ≦ 100, wherein the ratio of x to y is selected from the group consisting of y <x, x <y and x = y The electrochemical cell according to claim 12, wherein 16. The composition of the cathode may be (100-
y)% SVO + y% CF x, 0 ≦ y ≦ 100 / first current collector / (10
0 −x)% SVO + x% CFx, 0 ≦ x ≦ 100 / second current collector /
A (100 -y)% SVO + y % CF x, 0 ≦ y ≦ 100
13. The electrochemical cell according to claim 12, wherein the ratio of x and y is selected from the group consisting of y <x, x <y and x = y. 17. The composition of the cathode is (100−
y)% SVO + y% CF x, 0 ≦ y ≦ 100 / first current collector / (10
0−y)% SVO + y% CFx, 0 ≦ y ≦ 100 / (100−x
)% SVO + x% CFx, 0 ≦ x ≦ 100 / (100−y)% S
VO + y% CFx, 0 ≦ y ≦ 100 / second current collector / (100−y)
% SVO + y% CF _x , where 0 ≦ y ≦ 100, x and y
14. The electrochemical cell according to claim 12, wherein the ratio is selected from the group consisting of y <x, x <y and x = y. 18. The anode is lithium, and the weight ratio of the cathode is (100−y)% SVO + y% CF _x / current collector / (100−x)% SVO + x% CFx, where y < 13. The electrochemical cell according to claim 12, wherein x is (100-y)% SVO + y% CFx, with the cathode facing the lithium anode. 19. The anode is lithium, and the weight ratio of the cathode is (100−y)% SVO + y% CF _x / current collector / (100−x)% SVO + x% CFx, where x < in y a and and (100 -y)% SVO + y % CF x, electrochemical cell of claim 12 in which the cathode facing the lithium-made anode. 20. A third cathode structure in contact with a second current collector spaced from the second cathode structure, wherein the first cathode structure has first and second current collectors. In the middle of the body, the third cathode structure comprises (100-z)% (fifth percentage) of the first cathode active material and z% (sixth percentage) of the second cathode active material by weight. The electrochemical cell according to claim 12, wherein y <x and z <x, and y <z or y <z. 21. A cathode having a weight composition ratio of (100−y
)% First cathode active material + y% second cathode active material, 0
≦ y ≦ 100 / first current collector / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / second current collector / (100−z)% first Cathode active material + z% The second cathode active material, where 0 ≦ z ≦ 100 and y
21. The electrochemical cell according to claim 20, wherein ≤ x and z ≤ x, y <z or y> z. 22. A cathode having a weight composition ratio of (100−y
)% SVO + y% CFx, 0 ≦ y ≦ 100 / first current collector / (100
−x)% SVO + x% CFx, 0 ≦ x ≦ 100 / second current collector /
(100−z)% SVO + z% CFx, where 0 ≦ z ≦ 100
, Y ≦ x and z ≦ x, and further y <z or y> z
21. The electrochemical cell according to claim 20, wherein 23. Composition of the cathode in terms of weight percentage is (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / first current collector / (100−y)%
First cathode active material + y% Second cathode active material, 0 ≦ y
≦ 100 / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≤100 / second
Current collector / (100−y)% first cathode active material + y% second
A cathode active material, where 0 ≦ y ≦ 100, x and y
The electrochemical cell of claim 12, wherein the ratio of is selected from the group consisting of: y <x, x <y and x = y. 24. A cathode having a weight percentage composition of (10
0−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / first current collector / (100−y)% first cathode active material + y% second cathode active material, 0 ≤y ≤100 /
(100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / (100−z)% first cathode active material + z% second cathode active material, 0 ≦ z ≦ 100 / The second current collector / (100−z)% the first cathode active material + z% the second cathode active material, where 0 ≦ z ≦ 100, y ≦ x and
13. The electrochemical cell according to claim 12, wherein z? x and y <z or y> z. 25. A cathode having a weight composition ratio of (100−y
)% SVO + y% CFx, 0 ≦ y ≦ 100 / first current collector / (100
−y)% SVO + y% CFx, 0 ≦ y ≦ 100 / (100−x)%
SVO + x% CFx, 0 ≦ x ≦ 100 / (100−z)% SVO + z
% CFx, 0 ≦ z ≦ 100 / second current collector / (100−z)% SVO
25. The electrochemical cell according to claim 24, wherein + z% CFx, 0≤z≤100, y≤x and z≤x, and y <z or y> z. . 26. The first and second current collectors are stainless steel, titanium, tantalum, platinum, gold, aluminum, cobalt nickel alloy, high alloy ferritic stainless steel including molybdenum and chromium, and nickel-containing and chromium-containing. The electrochemical cell according to claim 12, wherein the electrochemical cell is selected from the group consisting of: a molybdenum-containing alloy. 27. The method according to claim 27, wherein the first and second current collectors are titanium and a coating selected from the group consisting of graphite / carbon material, iridium, iridium oxide and platinum is formed thereon. 13. The electrochemical cell according to claim 12, wherein: 28. The method of claim 12, wherein the anode is titanium, the first cathode active material is SVO, the second cathode active material is CFx, and the first and second current collectors are titanium. An electrochemical battery according to claim 1. 29. The method according to claim 29, wherein the first and second cathode active materials are SV
O, CSVO, V_TwoO_Five, MnO_Two, LiCoO_Two, LiNiO_Two, LiMnO_Two, CuO
_Two, TiS_Two, Cu_TwoS, FeS, FeS_Two, CFx, Ag_TwoO, Ag_TwoO _Two , CuF
 , Ag_TwoCrO_Four , Copper oxide, copper vanadium oxide and mixtures thereof
Selected from the group consisting of compounds
An electrochemical cell according to claim 12. 30. The non-aqueous electrolyte, wherein the first solvent is selected from esters, linear ethers, cyclic ethers, dialkalicarbonates and mixtures thereof, and the second solvent is cyclic carbonates, cyclic esters, cyclic amides and mixtures thereof. 13. The electrochemical cell according to claim 12, wherein the cell is selected from the group consisting of: 31. A method in which the first solvent is tetrahydrofuran (TH
F), methyl acetate (MA), diglyme, triglyme, tetraglyme, dimethyl carbonate (DMC), 1,
2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), 1-ethoxy, 2-methoxyethane (EME
), Ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate, dipropyl carbonate and mixtures thereof, wherein the second solvent is propylene carbonate (PC), ethylene carbonate (E
C), butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ-valerolactone, γ-butyrolactone (GBL), N-methyl-pyrrolidinone (NMP) and a mixture thereof. 31. The electrochemical cell according to claim 30, wherein: 32. As an electrolyte, LiPF ₆ , LiBF ₄ , LiAs
F ₆ , LiSbF ₆ , LiClO ₄ , LiO ₂ , LiAlCl ₄ , LiGaCl ₄ , LiC
(SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiSCN, LiO ₃ SCF ₃ , LiC ₆ F ₅ S
_{O 3, LiO 2 CCF 3,} LiSO 6 F, LiB (C 6 H 5) 4, LiCF 3 SO 3 and according to claim 12, characterized in that it comprises a lithium salt selected from the group consisting of a mixture thereof Electrochemical battery. 33. An electrolyte comprising a 50:50 mixture of propylene carbonate as a first solvent and 1,2-dimethoxyethane as a second solvent in a volume percentage of 50:50.
The electrochemical cell according to claim 12, characterized in that LiAsF ₆ or LiPF ₆ in 0.8M~1.5M is dissolved. 34. An electrochemical cell comprising: a) an anode; b) a first cathode structure and a second cathode structure, wherein the first cathode structure has first and second major sides. And at least one of the current collectors is in contact with at least one of the first and second major sides, and the second cathode structure is at least one of the current collectors facing the first cathode structure. A first cathode structure, in contact with one and facing the anode, includes a first cathode active material having a first energy density and a first rate capability, and a second cathode material having a second energy density and a second rate capability. From the active material, each is a first percentage by weight (100−x
)% And a second percentage, x%,
The second cathode structure is composed of the first cathode active material and the second cathode active material at a third percentage (100-y)% and a fourth percentage y%, respectively, by weight percentage; The first cathode active material is different from the second cathode active material when y ≦ x, the first energy density of the first cathode active material is smaller than the second energy density, and the first rate capability is the second energy density of the second cathode active material. An electrochemical cell, comprising: a cathode having greater than two-rate capacity; and c) an anode and a non-aqueous electrolyte for activating the cathode. 35. The composition of the cathode in terms of weight percentage is (100-y)% first cathode active material + y% second cathode active material / current collector / (100-x)% first cathode active material + x% 2 It is a cathode active material and the ratio of x and y is y
35. The electrochemical cell according to claim 34, wherein the cell is selected from the group consisting of <x, x <y and x = y. 36. The anode is lithium and the cathode
The composition in percentage by weight of is (100−y)% SVO + y
% CF_x / Current collector / (100-x)% SVO + x% CF _x Ah
And (100−y)% SVO + y% CF_x For y <x
The cathode faces the lithium anode.
35. The electrochemical cell according to claim 34, wherein
pond. 37. The composition in terms of weight percentage of the cathode is (100−y)% SVO + y% CF _x / current collector / (100 −
There x)% SVO + x% CF x, (100 -y)% SVO +
a y% CF _x for x <y, the electrochemical cell of claim 34 in which the cathode is characterized in that facing the anode made of lithium. 38. The method according to claim 38, wherein the first and second cathode active materials are SV.
_{O, CSVO, V 2 O 5} , MnO 2, LiCoO 2, LiNiO 2, LiMnO 2, Cu
O ₂ , TiS ₂ , Cu ₂ S, FeS, FeS ₂ , CF _x , Ag ₂ O, Ag ₂ O ₂ , CuF
The electrochemical cell according to claim 34, characterized in that it is selected from the group consisting of Ag ₂ CrO _4, copper oxide, vanadium oxide copper and mixtures thereof. 39. The first and second current collectors are stainless steel, titanium, tantalum, platinum, gold, aluminum, cobalt nickel alloy, high alloy ferritic stainless steel including molybdenum and chromium, and nickel-containing and chromium-containing. 35. The electrochemical cell of claim 34, selected from the group consisting of: a molybdenum-containing alloy. 40. An implantable device wherein a current pulse is discharged at least once to operate a function of the medical device where a substantially constant discharge current is required while the medical device is monitoring the function. An electrochemical cell for use in combination with a medical device, comprising: a) an anode; b) a first cathode structure sandwiched between first and second current collectors; A second cathode structure in contact with at least one of the current collectors facing the first cathode structure and facing the anode, wherein the first cathode structure has a weight ratio of (100−x)% (second 1%) of the first cathode active material and x% (the second percentage) of the second cathode active material,
The cathode structure is composed of (100-y)% (third percentage) of the first cathode active material and y% (fourth percentage) of the second cathode active material, and the first cathode active material is the second cathode active material. The first cathode active material has a first energy density and a first rate capability; the second cathode active material has a second energy density and a second rate capability; A cathode having a first energy density of the material less than the second energy density and a first rate capability greater than the second rate capability of the second cathode active material; and c) an anode and an electrolyte for activating the cathode. An electrochemical battery characterized by the above. 41. The medical device for monitoring function requires a current of about 1 microamp to about 100 milliamps,
41. The combination of claim 40, wherein the medical device operating the function requires between about 1 amp to about 4 amps of current. 42. The combination of claim 40, wherein the medical device for monitoring function is provided with first and second cathode active materials of the first and second cathode structures. 43. A medical device having a first energy density and a first rate capability as compared to a second cathode active material having substantially a second energy density and a second rate capability. 41. The combination of claim 40, wherein one cathode active material is provided, the second energy density is greater than the first energy density, and the first rate capability is greater than the second rate capability. 44. A method for providing an electrochemical cell, comprising: a) providing an anode; b) a first cathode structure shorted by a second cathode structure; Structure is (100-x)% by weight
(First percentage) of the first cathode active material and x%
(Second percentage) of the second cathode active material, wherein the second cathode structure comprises (100-y)% (third percentage) of the first cathode active material and y% (fourth percentage) of the second cathode active material. Wherein the first cathode active material is different from the second cathode active material, the first cathode active material has a first energy density and a first rate capability, and the second cathode active material is A cathode having a second energy density and a second rate capacity, wherein the first energy density of the first cathode active material is less than the second energy density, and the first rate capacity is greater than the second rate capacity of the second cathode active material. And c) activating the anode and cathode with a non-aqueous electrolyte. 45. The method of claim 44, wherein the ratio of x and y in the first and second cathode structures is selected from the group consisting of x <y, y <x and x = y. The described method. 46. The method according to claim 46, wherein the first and second cathode active materials are SV
_{O, CSVO, V 2 O 5} , MnO 2, LiCoO 2, LiNiO 2, LiMnO 2, Cu
O ₂ , TiS ₂ , Cu ₂ S, FeS, FeS ₂ , CF _x , Ag ₂ O, Ag ₂ O ₂ , CuF
_{, Ag 2 CrO 4, MnO 2} , copper oxide, comprising the step of selecting from the group consisting of vanadium oxide copper and mixtures thereof, The method of claim 44. 47. The composition in weight percent is (100 −
y)% first cathode active material + y% second cathode active material,
0 ≦ y ≦ 100 / current collector / (100−x)% first cathode active material + x% second cathode active material, 0 ≦ x ≦ 100 / current collector /
(100−y)% first cathode active material + y% second cathode active material, where 0 ≦ y ≦ 100 and the ratio of x to y
45. The method of claim 44, comprising providing a cathode selected from the group consisting of: y <x, x <y, and x = y. 48. The composition in percentage by weight is (100 −
y)% first cathode active material + y% second cathode active material,
0 ≦ y ≦ 100 / current collector / (100−y)% first cathode active material + y% second cathode active material, 0 ≦ y ≦ 100 / (100−
x)% first cathode active material + x% second cathode active material,
0 ≦ x ≦ 100 / (100−y)% first cathode active material + y
% Second cathode active material, 0 ≦ y ≦ 100 / current collector / (100−
y)% first cathode active material + y% second cathode active material, where 0 ≤ y ≤ 100 and the ratio of x to y is y <x,
45. A method for providing a cathode selected from the group consisting of x <y and x = y.
The method described in. 49. The composition in weight percentage is (100 −
y)% first cathode active material + y% second cathode active material /
Current collector / (100−x)% first cathode active material + x% second
It is a cathode active material and the ratio of x and y is y <x, x <y
45. The method of claim 44, comprising providing a cathode selected from the group consisting of and x = y. 50. The composition in weight percentage is (100 −
y)% SVO + y% CFx, 0 ≦ y ≦ 100 / current collector / (100 −
x)% SVO + x% CFx, 0 ≦ x ≦ 100 / current collector / (100−
y)% SVO + y% CFx, wherein 0≤y≤100 and wherein the ratio of x to y is selected from the group consisting of y <x, x <y and x = y. 47. The method of claim 44, comprising: 51. The composition in weight percent is (100 −
y)% SVO + y% CFx, 0 ≦ y ≦ 100 / current collector / (100 −
y)% SVO + y% CFx, 0 ≦ y ≦ 100 / (100−x)% SVO
+ X% CFx, 0 ≤ x ≤ 100 / (100-y)% SVO + y% C
Fx, 0 ≦ y ≦ 100 / current collector / (100−y)% SVO + y% C
Fx, 0 ≦ y ≦ 100, and the ratio of x to y is y <x, x
The method of claim 44, comprising providing a cathode selected from the group consisting of <y and x = y. 52. The anode is made of lithium, and the composition in weight percentage is (100−y)% SVO + y% CF _x /
Current collector / A (100 -x)% SVO + x % CF x,
In (100 -y)% SVO + y % CF x for y ≦ x, comprising the step of providing a cathode facing the lithium anode A method according to claim 44. 53. The anode is made of lithium and the composition in percentage by weight is (100−y)% SVO + y% CF _x /
Current collector / A (100 -x)% SVO + x % CF x,
In x ≦ y for (100 -y)% SVO + y % CF x, comprising the step of providing a cathode facing the lithium anode A method according to claim 44.