Analysis of the surface layer on a petroleum coke electrode in tetraglyme solutions of lithium salts

The surface layer on a petroleum coke in tetraglyme solutions of LiAsF 6 or LiCF 3SO 3 was analysed with X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy, Gas Chromatography and fluoride selective electrode. Results indicate that solvent reduction is a minor process and salt reduction a major one. Results are consistent with the reduction mechanism of LiAsF 6 proposed in the literature. But with LiCF 3SO 3, we suggest that reduction proceeds via the cleavage of a CF bond instead of a CS bond.