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US 6,274,269 B1Granted
Method for reducing voltage delay in alkali metal electrochemical cells activated with a nonaqueous electrolyte having a phosphate additive
AssigneeWilson Greatbatch Ltd.
InventorsHong Gan, Esther S. Takeuchi
Life of this patent
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Abstract
An alkali metal, solid cathode, nonaqueous electrochemical cell capable of delivering high current pulses, rapidly recovering its open circuit voltage and having high current capacity, is described. The stated benefits are realized by the addition of at least one phosphate additive to an electrolyte comprising an alkali metal salt dissolved in a mixture of a low viscosity solvent and a high permittivity solvent. A preferred solvent mixture includes propylene carbonate, dimethoxyethane and an alkyl phosphate additive.
Claims25
A method of reducing voltage delay in a pulse discharging electrochemical cell activated with a nonaqueous electrolyte, comprising the steps of:
- a) providing an anode comprising an alkali metal;
- b) providing a solid cathode of electrically conductive material;
- c) activating the electrochemical cell with the nonaqueous electrolyte operatively associated with the anode and the cathode, the nonaqueous electrolyte comprising:
- i) a phosphate additive having the general formula:
- (R1O)P(═O)(OR2)(OR3), wherein R1, R2 and R3 are the same or different and they can be a hydrogen atom or an organic group, with at least one of them being an unsaturated organic group containing 2 to 13 carbon atoms and having the formula CR4R5R6 with at least R4 being an aromatic substituent or an unsaturated organic or inorganic group and wherein if any of the remaining groups of R1, R2 and R3 is a saturated organic group, the saturated organic group contains 1 to 13 carbon atoms;
- and
- ii) an alkali metal salt dissolved therein;
- and
- d) discharge the cell to deliver at least one current pulse of an electrical current of a greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.
6 more elements
A method of reducing voltage delay in a pulse discharging electrochemical cell activated with a nonaqueous electrolyte, comprising the steps of:
- a) providing an anode comprising an alkali metal;
- b) providing a cathode including a mixed metal oxide comprised of vanadium oxide and a second metal “SM” selected from the group consisting of Groups IB, IIB, IIIB, IVB, VIB, VIIB and VIII of the Periodic Table of the Elements, the mixed metal oxide having the general formula SMxV2Oy, wherein 0.30≦x≦2.0 and 4.5≦y≦6.0;
- c) activating the electrochemical cell with the nonaqueous electrolyte operatively associated with the anode and the cathode, the nonaqueous electrolyte comprising:
- i) a first solvent selected from the group consisting of an ester, an ether and a dialkyl carbonate, and mixtures thereof;
- ii) a second solvent selected from the group consisting of a cyclic carbonate, a cyclic ester and a cyclic amide, and mixtures thereof;
- iii) a phosphate additive having the general formula:
- (R1O)P(═O)(OR2)(OR3), wherein R1, R2 and R3 are the same or different and they can be a hydrogen atom or an organic group, with at least one of them being an unsaturated organic group containing 2 to 13 carbon atoms and having the formula CR4R5R6 with at least R4 being an aromatic substituent or an unsaturated organic or inorganic group and wherein if any of the remaining groups of R1, R2 and R3 is a saturated organic group, the saturated organic group contains 1 to 13 carbon atoms;
- and
- iv) an alkali metal salt dissolved therein;
- and
- d. discharge the cell to deliver at least one current pulse of a short duration burst of electrical current of a significantly greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.
8 more elements
A method of reducing voltage delay in a pulse discharging electrochemical cell activated with a nonaqueous electrolyte, comprising the steps of:
- a) providing an anode comprising an alkali metal;
- b) providing a cathode including a mixed metal oxide comprised of vanadium oxide and a mixture of copper and a second metal “SM” selected from the group consisting of groups IB, IIB, IIIB, IVB, VIB, VIIB, and VIII of the Periodic Table of the Elements, the mixed metal oxide having the general formula CuxSMyV2Oz wherein 0.01≦x≦1.0, 0.01≦y≦1.0 and 5.01≦z≦6.5;
- c) activating the electrochemical cell with the nonaqueous electrolyte operatively associated with the anode and the cathode, the nonaqueous electrolyte comprising:
- i) a first solvent selected from the group consisting of an ester, an ether and a dialkyl carbonate, and mixtures thereof;
- ii) a second solvent selected from the group consisting of a cyclic carbonate, a cyclic ester and a cyclic amide, and mixtures thereof;
- iii) a phosphate additive having the general formula:
- (R1O)P(═O)(OR2)(R3), wherein R1, R2 and R3 are the same or different and they can be a hydrogen atom or an organic group, with at least one of them being an unsaturated organic group containing 2 to 13 carbon atoms and having the formula CR4R5R6 with at least R4 being an aromatic substituent or an unsaturated organic or inorganic group and wherein if any of the remaining groups of R1, R2 and R3 is a saturated organic group, the saturated organic group contains 1 to 13 carbon atoms;
- and
- iv) an alkali metal salt dissolved therein;
- and
- d) discharge the cell to deliver at least one current pulse of an electrical current of a greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.
8 more elements
Dependencies are inferred from the claim text.