Patent ID: 7675737

Claim:
A non-aqueous electrolyte for electrochemical devices that function below −50° C. which comprises a mixture, eutectic or tereutectic of at least two low viscosity aprotic solvents which includes 20 to 75% acetonitrile and a mixture of conductive salts having a molecular weight of up to 240 selected from the group consisting of; a) an imidazolium compound of the formula: wherein R 1 , R 2 , R 3 , R 4 , and R 5 are the same or different and are selected from the group consisting of hydrogen, an alkyl group of 1-4 carbon atoms, or fluoroalkyl, with the proviso that at least one of R 1 , R 2 , R 3 , R 4 , and R 5 being hydrogen; b) an ammonium compound of the formula: wherein R 5 , R 6 , R 7 , and R 8 are the same or different and consists of alkyl group of 1-4 carbon atoms, or fluoroalkyl, and c) a pyrrolidinyl compound of the formula; wherein R 8 , and R 9 are the same or different and consists of alkyl group of 1-4 carbon atoms, and an anion selected from the group consisting of tetrafluoroborate (BF 4 − ), hexafluoroarsenate (AsF6) − , hexafluorophosphate (PF 6 − ), fluoro hydrogen fluoride F(HF)x − , wherein x=1 to 4, (SbF 6 − ), (CF 3 BF 3 − ), trifluoromethylsulfonate (triflate), and bis (trifluoromethylsufonyl) imide.