Inhibition of anodic corrosion of aluminum cathode current collector on recharging in lithium imide electrolytes

Fitting corrosion of aluminum as cathode current collector for lithium rech argeable batteries was found to take place at potential positive of 3.5 V i n 1 mol dm(-3) LiN(SO2CF3)(2)/EC + DME (1:1) electrolyte. The corrosion mec hanism of aluminum in the presence of LIN(SO2CF3)(2) was proposed, and thre e methods were deduced to inhibit the aluminum corrosion based on this mech anism. As a result, an additive of lithium salts based on perfluorinated in organic anions, especially LiPF6, was found to inhibit the aluminum corrosi on to a certain extent by forming a protective film on aluminum surface. Th e oxidation stability of aluminum in LiN(SO2CF3)(2)-containing electrolytes depended strongly on the solvent structure. The ether solvents such as tet rahydrofuran (THF) and dimethoxyethane (DME) were effective in preventing a luminum corrosion due to their low dielectric constants. Furthermore, LiN(S O2C2F5)(2) salt with a larger anion than that of LIN(SO2CF3)(2) was evaluat ed and good oxidation stability of waluminum was obtained regardless of the kind of solvents. (C) 2000 Elsevier Science Ltd. All rights reserved.