Six lithium salts of tris-and tetrakis͑polyfluoroalkoxy͒aluminate superweak anions have been studied for their potential use as battery electrolytes. Four of the six are based on the formula LiAl͑OCR͑CF 3 ) 2 ) 4 (R ϭ H, Me, CF 3 , Ph); the other two are LiAl͑OCH 2 CF 3 ) 4 and LiAlF͑OCPh͑CF 3 ) 2 ) 3 . The thermally stable electrolytes LiAl͑OCH͑CF 3 ) 2 ) 4 and LiAl͑OCPh͑CF 3 ) 2 ) 4 were not oxidized at potentials less than or equal to 5.0 V vs. Li ϩ/0 in dimethoxyethane ͑DME͒ or in 50:50% ethylene carbonate:dimethylcarbonate ͑EC:DMC͒. The LiAl͑OCH͑CF 3 ) 2 ) 4 electrolyte was not reduced at 0 V vs. Li ϩ/0 in DME. Neither LiAl͑OCH͑CF 3 ) 2 ) 4 nor LiAl͑OCPh͑CF 3 ) 2 ) 4 promoted the corrosion of aluminum at 5.0 V vs. Li ϩ/0 . The electrolyte LiAl͑OCH͑CF 3 ) 2 ) 4 underwent efficient, reversible reductive intercalation of Li ϩ with MCMB carbon or LiCoO 2 electrodes over the potential ranges 0-2 and 2.4-4.8 V, respectively, vs. Li ϩ/0 , but did not react in any other way with these electrode materials. The conductivities of some of the LiAl͑OR F ) 4 electrolytes in DME or in EC:DMC were high enough for them to be considered as potential replacements for LiPF 6 in primary and secondary lithium batteries.

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