Non-aqueous electrolytes for electrochemical cells

1. A non-aqueous electrolyte comprising:

an alkali metal salt;

from 0.01 wt % to 10 wt % vinylene carbonate, fluorinated ethylene carbonate, biphenyl, or cyclohexyl benzene;

an aprotic solvent; and

a siloxane compound represented by Formula III:

wherein:

the siloxane compound is present at a concentration from about 0.5 to about 5 weight percent of the electrolyte;

the alkali metal salt is present at a concentration from about 0.01 M to about 2 M;

each R′ is represented by Formula I-A:

each R″ is represented by R, Formula I-A, or I-B;

each R is individually H, an alkyl group, an alkenyl group, an alkynyl group, an alk(poly)enyl group, an alk(poly)ynyl group, or an aryl group;

R 1 is a fluorinated alkylene group, an alkylene oxide group, a fluorinated alkylene oxide group, an ether group, or a fluorinated ether group;

R 2 is a bond, a fluorinated alkylene group, an alkylene oxide group, a fluorinated alkylene oxide group, an ether group, or a fluorinated ether group;

R 3 is an alkyl group or an aryl group;

m is 0-15;

n is 1 or 2; and

p is 1, 2, or 3.

2. The non-aqueous electrolyte of claim 1 , wherein R 1 is a fluorinated alkylene, fluorinated alkylene oxide, or fluorinated ether and R 2 is a bond, a fluorinated alkylene, fluorinated alkylene oxide, or fluorinated ether.

3. The non-aqueous electrolyte of claim 1 , wherein the aprotic solvent comprises a silicon-based solvent or an organic solvent.

4. The non-aqueous electrolyte of claim 1 , wherein the aprotic solvent comprises a cyclic carbonate, linear carbonate, dialkyl carbonate, aliphatic carbonxylate ester, γ-lactone, linear ether, cyclic ether, or a fluorinated carboxylate ester.

5. The non-aqueous electrolyte of claim 1 , wherein the alkali metal salt comprises Li[(C 2 O 4 ) 2 B], Li(C 2 O 4 )BF 2 , LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 2 N, Li(CF 3 SO 2 ) 3 C, LiN(SO 2 C 2 F 5 ) 2 , or a lithium alkyl fluorophosphate.

6. The non-aqueous electrolyte of claim 1 , wherein the concentration of the alkali metal salt is from 0.5M to 2.0M.

7. An electrochemical cell comprising:

a negative electrode intercalated with lithium;

a positive electrode comprising an electrode active material which intercalates with lithium; and

the non-aqueous electrolyte of claim 1 .

8. The electrochemical cell of claim 7 , wherein the negative electrode comprises graphite particles or silicon particles.