Thionyl chloride (SOCl2), sulfuryl chloride (SO2Cl2), dimethyl sulfoxide (DMSO), benzenesulfonyl chloride (BSC) and phenyl vinyl sulfoxide (PVSO) were used as electrolyte additives in 1 mol•L－1 LiPF6-EC/DMC to examine the electrochemical reversibility of lithium deposition-dissolution and the influence on the interface property between lithium metal anode and the electrolyte. The related research tools and methods include constant current deposition and dissolution, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The electrochemical test results indicate that SO2Cl2 and BSC additives can remarkably improve the cycling performance of lithium metal anode. The cycling efficiency is stabilized at 90% under 100% DOD (complete deposition-dissolution). Electrochemical tests, in combination with calculation of electron affinities and XPS results, reveal that a preferential filming reaction of SO2Cl2 with BSC can suppress the electrolyte decomposition and improve the cycling efficiency and life-span of the lithium anode. Judged from the additive structures, sulfuryl compounds are superior over sulfinyl ones.

Key words: sulfinyl and sulfuryl compound, additive, rechargeable lithium battery, lithium metal anode, electrochemical reversibility