Additives to improve electrolyte performance in lithium ion batteries

1. A lithium ion battery comprising:

a) a stabilized manganese cathode comprising:

a lithium-containing manganese composite oxide having a spinel structure as active material, the lithium-containing manganese composite oxide being represented by the formula:

Li x Ni y M z Mn 2-y-z O 4-d ,

wherein x is 0.03 to 1.0; x changes in accordance with release and uptake of lithium ions and electrons during charge and discharge; y is 0.3 to 0.6; M comprises one or more of Cr, Fe, Co, Li, Al, Ga, Nb, Mo, Ti, Zr, Mg, Zn, V, and Cu; z is 0.01 to 0.18, and d is 0 to 0.3;

b) an anode;

c) a porous separator between said anode and said cathode;

d) a nonaqueous electrolyte composition providing an ionically conductive pathway between said anode and said cathode, wherein said electrolyte comprises:

(i) a solvent mixture comprising:

(A) ethylene carbonate at about 10% to about 40% by weight;

(B) at least one fluorine-containing carboxylic acid ester selected from the group consisting of CH 3 —COO—CH 2 CF 2 H, CH 3 CH 2 —COO—CH 2 CF 2 H, F 2 CHCH 2 —COO—CH 3 , F 2 CHCH 2 —COO—CH 2 CH 3 , CH 3 —COO—CH 2 CH 2 CF 2 H, CH 3 CH 2 —COO—CH 2 CH 2 CF 2 H, and F 2 CHCH 2 CH 2 —COO—CH 2 CH 3 at about 20% to about 80% by weight; and

(C) at least one phosphate additive at about 0.2% to about 10% by weight, said at least one phosphate additive represented by the formula:

wherein R 1 , R 2 , and R 3 are each independently normal or branched C1 to C10 alkyl or fluoroalkyl, C3 to C10 cyclic alkyl, C2 to C10 ether, C2 to C10 ether wherein at least one of the hydrogens is replaced with a fluorine, R 1 and R 2 , R 2 and R 3 , or R 1 and R 3 may be joined to form a ring; and

(ii) at least one electrolyte salt.

2. The lithium ion battery of claim 1 , wherein the electrolyte composition further comprises 4-fluoroethylene carbonate at a concentration of about 0.5% to about 2% by weight.

3. The lithium ion battery of claim 1 , wherein the solvent mixture comprises ethylene carbonate and CH 3 —COO—CH 2 CF 2 H, or CH 3 CH 2 —COO—CH 2 CF 2 H at a weight ratio of about 30:70 and the phosphate additive at about 1% by weight.

4. The lithium ion battery of claim 1 , wherein the phosphate additive is selected from the group consisting of tris(1,1,1,3,3,3-hexafluoropropan-2yl) phosphate, tris(2,2,2-trifluoroethyl) phosphate, tri(2,2,3,3,3-pentafluoropropyl) phosphate, tris(2,2,3,3-tetrafluoropropyl) phosphate, triethyl phosphate, trimethyl phosphate, tripropyl phosphate, triphenyl phosphate, triisopropyl phosphate, tris(2,2,3,3,4,4,5,5,6,6-decafluorohexyl) phosphate, and tris(2,2-difluoroethyl) phosphate.

5. The lithium ion battery of claim 1 , wherein the anode is lithium titanate or graphite.

6. The lithium ion battery of claim 1 , wherein y is 0.38 to 0.48, z is 0.03 to 0.12, and d is 0 to 0.1.

7. The lithium ion battery of claim 1 , wherein M is one or more of Li, Cr, Fe, Co, and Ga.

8. An electronic device that comprises a lithium ion battery according to claim 1 .

9. A lithium ion battery comprising:

a) a stabilized manganese cathode comprising:

a lithium-containing manganese composite oxide having a spinel structure as active material, the lithium-containing manganese composite oxide being represented by the formula:

Li x Ni y M z Mn 2-y-z O 4-d ,

wherein x is 0.03 to 1.0; x changes in accordance with release and uptake of lithium ions and electrons during charge and discharge; y is 0.3 to 0.6; M comprises one or more of Cr, Fe, Co, Li, Al, Ga, Nb, Mo, Ti, Zr, Mg, Zn, V, and Cu; z is 0.01 to 0.18, and d is 0 to 0.3;

b) an anode;

c) a porous separator between said anode and said cathode;

d) a nonaqueous electrolyte composition providing an ionically conductive pathway between said anode and said cathode, wherein said electrolyte comprises:

(i) a solvent mixture comprising:

(A) ethylene carbonate at about 15% to about 40% by weight;

(B) at least one fluorine-containing carboxylic acid ester selected from the group consisting of CH 3 —COO—CH 2 CF 2 H, CH 3 CH 2 —COO—CH 2 CF 2 H, F 2 CHCH 2 —COO—CH 3 , F 2 CHCH 2 —COO—CH 2 CH 3 , CH 3 —COO—CH 2 CH 2 CF 2 H, CH 3 CH 2 —COO—CH 2 CH 2 CF 2 H, and F 2 CHCH 2 CH 2 —COO—CH 2 CH 3 at about 40% to about 80% by weight; and

(C) at least one phosphate additive at about 0.5% to about 5% by weight, said at least one phosphate additive represented by the formula:

wherein R 1 , R 2 , and R 3 are each independently normal or branched C1 to C10 alkyl or fluoroalkyl, C3 to C10 cyclic alkyl, C2 to C10 ether, C2 to C10 ether wherein at least one of the hydrogens is replaced with a fluorine, R 1 and R 2 , R 2 and R 3 , or R 1 and R 3 may be joined to form a ring; and

(ii) at least one electrolyte salt.

10. The lithium ion battery of claim 9 , wherein the electrolyte composition further comprises 4-fluoroethylene carbonate at a concentration of about 0.5% to about 2% by weight.

11. The lithium ion battery of claim 9 , wherein the solvent mixture comprises ethylene carbonate and CH 3 —COO—CH 2 CF 2 H, or CH 3 CH 2 —COO—CH 2 CF 2 H at a weight ratio of about 30:70 and the phosphate additive at about 1% by weight.

12. The lithium ion battery of claim 9 , wherein the phosphate additive is selected from the group consisting of tris(1,1,1,3,3,3-hexafluoropropan-2yl) phosphate, tris(2,2,2-trifluoroethyl) phosphate, tri(2,2,3,3,3-pentafluoropropyl) phosphate, tris(2,2,3,3-tetrafluoropropyl) phosphate, triethyl phosphate, trimethyl phosphate, tripropyl phosphate, triphenyl phosphate, triisopropyl phosphate, tris(2,2,3,3,4,4,5,5,6,6-decafluorohexyl) phosphate, and tris(2,2-difluoroethyl) phosphate.

13. The lithium ion battery of claim 9 , wherein the anode is lithium titanate or graphite.

14. The lithium ion battery of claim 9 , wherein y is 0.38 to 0.48, z is 0.03 to 0.12, and d is 0 to 0.1.

15. The lithium ion battery of claim 9 , wherein M is one or more of Li, Cr, Fe, Co, and Ga.

16. An electronic device that comprises a lithium ion battery according to claim 9 .