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US 6,203,942 B1Granted
Phosphate additives for nonaqueous electrolyte rechargeable electrochemical cells
AssigneeWilson Greatbatch Ltd.
InventorsHong Gan, Esther S. Takeuchi
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Abstract
A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible 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 solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an alkyl phosphate compound.
Claims39
An electrochemical cell, which comprises:
- a) a negative electrode which intercalates with an alkali metal;
- b) a positive electrode comprising an electrode active material which intercalates with the alkali metal;
- c) a nonaqueous electrolyte activating the negative and the positive electrodes;
- and
- d) a phosphate additive provided in the electrolyte, wherein the phosphate additive has the formula:
- (R1O)P(═O)(OR2)(OR3) and wherein R1, R2 and R3 are the same or different, wherein at least one, but not all three, of the R groups is hydrogen, wherein the remaining groups which are not hydrogen are saturated organic groups containing 1 to 13 carbon atoms or unsaturated organic groups containing 2 to 13 carbon atoms.
3 more elements
An electrochemical cell, which comprises:
- a) a negative electrode which intercalates with lithium;
- b) a positive electrode comprising an electrode active material and which intercalates with lithium;
- c) an electrolyte solution activating the anode and the cathode, the electrolyte including an alkali metal salt dissolved in a quaternary, nonaqueous carbonate solvent mixture of ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate;
- and
- d) a phosphate additive provided in the electrolyte, wherein the phosphate additive has the formula:
- (R1O)P(═O)(OR2)(OR3) and wherein R1, R2 and R3 are the same or different, wherein at least one, but not all three, of the R groups is hydrogen, wherein the remaining groups which are not hydrogen are saturated organic groups containing 1 to 13 carbon atoms or unsaturated organic groups containing 2 to 13 carbon atoms.
3 more elements
An electrochemical cell, which comprises:
- a) an anode comprising an active material capable of intercalating an alkali metal;
- b) a solid cathode of electrically conductive material;
- and
- c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising a phosphate additive having the general formula:
- (R1O)P(═O)(OR2)(OR3), wherein at least one, but not all three, of the R groups is hydrogen, the remaining R groups which are not hydrogen being saturated organic groups containing 1 to 13 carbon atoms or unsaturated organic groups containing 2 to 13 carbon atoms.
2 more elements
An electrochemical cell, which comprises:
- a) an anode of a carbonaceous material capable of intercalating lithium;
- b) a cathode comprising lithium cobalt oxide;
- and
- c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising a phosphate additive, wherein the phosphate additive has the formula:
- (R1O)P(═O)(OR2)(OR3) and wherein R1, R2 and R3 are the same or different, wherein at least one, but not all three, of the R groups is hydrogen, wherein the remaining groups which are not hydrogen are saturated organic groups containing 1 to 13 carbon atoms or unsaturated organic groups containing 2 to 13 carbon atoms.
2 more elements
A method for providing an electrochemical cell, comprising the steps of:
- a) providing a negative electrode which intercalates with an alkali metal;
- b) providing a positive electrode comprising an electrode active material which intercalates with the alkali metal;
- c) activating the negative and positive electrodes with a nonaqueous electrolyte;
- and
- d) providing a phosphate additive in the electrolyte, wherein the phosphate additive has the formula:
- (R1O)P(═O)(OR2) (OR3) and wherein R1, R2 and R3 are the same or different, wherein at least one, but not all three, of the R groups is hydrogen, wherein the remaining groups which are not hydrogen are saturated organic groups containing 1 to 13 carbon atoms or unsaturated organic groups containing 2 to 13 carbon atoms.
3 more elements
An electrochemical cell, which comprises:
- a) a negative electrode which intercalates with an alkali metal;
- b) a positive electrode comprising an electrode active material which intercalates with the alkali metal;
- c) a nonaqueous electrolyte activating the negative and the positive electrodes;
- and
- d) dibenzyl phosphate provided in the electrolyte at a concentration up to about 0.20M.
2 more elements
A method for providing an electrochemical cell, comprising the steps of:
- a) providing a negative electrode which intercalates with an alkali metal;
- b) providing a positive electrode comprising an electrode active material which intercalates with the alkali metal;
- c) activating the negative and positive electrodes with a nonaqueous electrolyte;
- and
- d) providing dibenzyl phosphate in the electrolyte at a concentration up to about 0.20M.
2 more elements
Dependencies are inferred from the claim text.