Non-aqueous electrolyte for lithium-ion battery

1. A substantially non-aqueous electrolyte solution comprising:

an alkali metal salt;

a polar aprotic solvent; and

an organophosphorus compound of Formula IA or IB:

wherein:

R 1 , R 2 , R 3 and R 4 are each independently hydrogen, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, alkenoxy, alkynoxy, cycloalkoxy, aryloxy, heterocyclyloxy, heteroaryloxy, siloxyl, silyl, or organophosphatyl;

R 5 and R 6 are each independently alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl;

R 7 is

provided that if the organophosphorus compound is of Formula IB, then at least one of R 5 , and R 6 are other alkyl, alkenyl or aryl.

2. The electrolyte of claim 1 , wherein the organophosphorus compound is present in the electrolyte from about 0.0005 wt % to about 50 wt %.

3. The electrolyte of claim 1 , wherein the alkali metal salt is a lithium salt.

4. The electrolyte of claim 3 , wherein the alkali metal salt comprises LiPF 6 , LiClO 4 , Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], Li[PF 4 (C 2 O 4 )], Li[N(CF 3 SO 2 ) 2 ], Li[C(SO 2 CF 3 ) 3 ], Li[N(C 2 F 5 SO 2 ) 2 ], LiCF 3 SO 3 , Li 2 B 12 X 12-n H n , Li 2 B 10 X 10-n′ H n′ , LiAlF 4 , LiBF 4 , Li(FSO 2 ) 2 N, Li 2 SO 4 , LiAlO 2 LiSCN, LiBr, LiI, LiAsF 6 , LiB(Ph) 4 , LiSO 3 CH 3 , Li 2 S x″ , Li 2 Se x″ , (LiS x′ R) y or (LiSe x′ R) y ; wherein X is a halogen, n is an integer from 0 to 12, n′ is an integer from 0 to 10, x″ is an integer from 1 to 20, y is an integer from 1 to 3, and R is H, alkyl, alkenyl, aryl, ether, F, CF 3 , COCF 3 , SO 2 CF 3 , SO 2 F, or a mixture of any two or more thereof.

5. The electrolyte of claim 1 , wherein the polar aprotic solvent is ethyl acetate, propyl acetate, dimethyl ether, diethyl ether, methyl acetate, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, bis(trifluoroethyl) carbonate, bis(pentafluoropropyl) carbonate, trifluoroethyl methyl carbonate, pentafluoroethyl methyl carbonate, heptafluoropropyl methyl carbonate, perfluorobutyl methyl carbonate, trifluoroethyl ethyl carbonate, pentafluoroethyl ethyl carbonate, heptafluoropropyl ethyl carbonate, perfluorobutyl ethyl carbonate, fluorinated oligomers, dimethoxyethane, triglyme, dimethylvinylene carbonate, tetraethyleneglycol, dimethyl ether, polyethylene glycols, sulfones, or gamma-butyrolactone.

6. The electrolyte of claim 1 , wherein R 1 , R 2 , R 3 and R 4 are each independently methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, 2-propenyl, 3-butenyl, 2-propynyl or 3-butynyl.

7. The electrolyte of claim 1 , wherein the organophosphorus compound is of Formula IA.

8. The electrolyte of claim 1 , wherein the organophosphorus compound is of Formula IB.

9. The electrolyte of claim 1 , wherein the electrolyte further comprises a compound of formula:

10. A substantially non-aqueous electrolyte solution comprising:

an alkali metal salt;

a polar aprotic solvent; and

an organophosphorus compound of formula:

11. A substantially non-aqueous electrolyte solution comprising:

an alkali metal salt;

a polar aprotic solvent; and

an organophosphorus compound of formula:

12. A substantially non-aqueous electrolyte solution comprising:

an alkali metal salt;

a polar aprotic solvent; and

an organophosphorus compound of formula:

13. An electrochemical device comprising

a cathode

an anode;

a porous separator which separates the anode and the cathode; and

the electrolyte of claim 1 .

14. The electrochemical device of claim 13 , wherein the device is a lithium secondary battery.

15. The electrochemical device of claim 13 , wherein the cathode comprises a lithium metal oxide.

16. The electrochemical device of claim 13 , wherein the anode comprises a carbon material or a lithium metal.

17. The electrochemical device of claim 16 , wherein the anode is a natural graphite or a hard carbon anode.