Electrochemical behavior of Al current collector of rechargeable lithium batteries in propylene carbonate with LiCF3SO3, Li(CF3SO2)2N, or Li(C4F9SO2)(CF3SO2)N

A corrosion of Al in nonaqueous electrolytes containing LiCF3SO3Li(CF3SO2)(2)N, or Li(CF3SO3)(C4F9SO3)N was investigated by using electrochemical methods and surface analyses (X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy). The corrosion actively occurred in propylene carbonate (PC) containing LiCF3SO3 or Li(CF3SO2)(2)N at more cathodic potential than 3.8 V vs. Li/Li+. These results indicate that LiCF3SO3 and Li(CF3SO2)(2)N do not provide a good passivation surface film on the Al electrode. In order to suppress the corrosion, a small amount of HF was added. This additive produced a new surface film that worked as a passivation film. However, the corrosion of Al was still observed in the potential region more anodic than 3.8 V vs. Li/Li+. On the other hand, Al electrode was stable in PC containing Li(C4F9SO2)(CF3SO2)N. In this electrolyte, the surface film on Al works as a passivation film, probably due to a large distribution of negative charge on this electrolyte. (C) 2002 The Electrochemical Society.