Aluminum corrosion in electrolyte of Li-ion battery

The effect of lithium salt and electrolyte solvent on Al corrosion in Li-ion battery electrolytes was studied by using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results showed that, in 1:1 (w/w) ethylene carbonate (EC)/1,2-dimethoxyethane (DME) solutions, the pitting potential of Al corrosion is about 3.2 V versus Li+/Li, being independent of the type of salts. However, the salt has considerable impact on Al corrosion. Among the studied Li salts, the stability of Al with respect to the oxidative potentials was found to increase in an order of CF3SO3Li < LiN(SO2CF3)(2) < LiClO4 < LiPF6 < LiBF4. We observed that a combination of two salts, such as LiPF6 and CF3SO3Li, lowers the pitting potential and aggravates Al corrosion. Addition of compounds, which contain active fluoride, such as perfluoro-l-butanesulfonyl fluoride (C4F9SO2F), into electrolytes can increase the pitting potential but cannot suppress Al corrosion. (C) 2002 Elsevier Science B.V. All rights reserved.