Electrochemical Behavior of Al Current Collector of Rechargeable Lithium Batteries in Propylene Carbonate with LiCF[sub 3]SO[sub 3], Li(CF[sub 3]SO[sub 2])[sub 2]N, or Li(C[sub 4]F[sub 9]SO[sub 2])(CF[sub 3]SO[sub 2])N

Abstract

A corrosion of Al in nonaqueous electrolytes containing LiCF3SO3,LiCF3SO3, Li(CF3SO2)2N,Li(CF3SO2)2N, or Li(CF3SO3)(C4F9SO3)NLi(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 LiCF3SO3LiCF3SO3 or Li(CF3SO2)2NLi(CF3SO2)2N at more cathodic potential than 3.8 V vs. Li/Li+.Li/Li+. These results indicate that LiCF3SO3LiCF3SO3 and Li(CF3SO2)2NLi(CF3SO2)2N 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+.Li/Li+. On the other hand, Al electrode was stable in PC containing Li(C4F9SO2)(CF3SO2)N.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. © 2002 The Electrochemical Society. All rights reserved.