锂离子电池电解液成膜添加剂乙烯基亚硫酸乙烯酯的电化学行为

Electrochemical Behavior of Vinyl Ethylene Sulfite as an Electrolyte Film-forming Additive in Lithium Ion Batteries

研究了具有不饱和双键和亚硫酸酯双官能团的乙烯基亚硫酸乙烯酯(VES)作为锂离子电池电解液成膜添加剂对中间相碳微球(CMS)和LiFePO4电极电化学性能的影响.结果表明:在1mol/LLiClO4/PC电解液体系中,少量的VES(5%)能够在电化学过程中先于PC在CMS表面还原,形成稳定的SEI膜,明显抑制PC和溶剂化锂离子共嵌入石墨层间,改善了电池的循环性能.此外,电解液1mol/LLiClO4/PC+5%VES(V∶V)在LiFePO4电极中展现出良好的电化学稳定性.

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.