Study of SEI forming process with Li BOB-DMS/SL electrolyte in first cycle

Abstract

Lithium bis (oxalate) borate (Li BOB) has attracted much attention as a lithium salt or an additive in no aqueous electrolyte for lithium-ion battery. Tn this work, the formation of a solid electrolyte interphase (SET) film of sulfolane (SL) with Li BOB was studied by employment of dimethyl sulfite (DMS) as mixed solvents. When used in Li/MCMB (mesosphere carbon micro beads) cells, cell with 0.7M Li BOB-zSL/DMS (1:1) electrolyte at high temperature shows lower impedance than that at room temperature. The scanning electron microscope (SEM) results find that 0.7M Li BOB-SL/DMS (1:1) electrolyte at high temperature shows excellent film-forming characteristics than that at room temperature. The Li2SO3, ROSO2Li, Li2S, Li2CO3 substances are found in SET film by X-ray photoelectron spectroscopy (XPS). It suggests that Li BOB-SL/DMS electrolyte has an excellent solid electrolyte interphase formation capacity.