Electrochemical behavior of vinyl ethylene sulfite as an electrolyte film-forming additive in lithium ion batteries

A film-forming additive, vinyl ethylene sulfite (VES) with both vinylene group and sulfite group, affects the electrochemical performance of carbonaceous mesophase spherules (CMS) and LiFePO4 electrode. The results indicated that a small amount of VES (5%) could be reduced prior to the propylene carbonate (PC) solvent on the surface of CMS electrode in PC-based electrolyte to form a stable solid electrolyte interphase (SEI) layer, so co-intercalation of PC and solvated lithium ions to graphite could be suppressed. Furthermore, the electrolyte of 1 mol/L LiClO4/PC+5%VES (V:V) exhibited excellent electrochemical stability in the LiFePO4 electrode