【摘要】 使用尖晶石LiMn2O4作为锂离子蓄电池阴极材料,采用恒电流充放电和粉末微电极的循环伏安方法对比研究了电解液中痕量HF对不同电解质溶液体系电化学性能的影响。结果发现, 在1 mol·L-1 LiClO4/(EC+DMC)(体积比为1∶1)电解液中,痕量HF对尖晶石LiMn2O4正极材料的电化学嵌脱锂性能有一定的改善和提高。这是因为在1 mol·L-1 LiClO4/(EC+DMC)电解液中,HF与LiClO4间特殊的相互作用有利于电极界面在首次充电过程中建立有效的固体电解质相界面(SEI)膜,从而改善了电极材料的结构稳定性,提高了电极电化学性能。但HF添加量过大时,电极/电解液相界面形成的SEI膜太厚,导致电极与电解液间的高界面电阻,反而造成尖晶石LiMn2O4电化学性能下降。更多还原

【Abstract】 Spinel LiMn2O4 was employed as cathode material for lithium ion batteries. Influences of trace HF in non-aqueous electrolytes on the electrochemical properties of spinel LiMn2O4 were comparatively examined by means of chronopotentiometry and cyclic voltametry techniques. Results show that the addition of trace HF significantly improves the electrochemical properties of spinel LiMn2O4 in 1 mol·L-1 LiClO4/(EC+DMC)(1∶1) electrolyte. The positive effects of HF in 1 mol·L-1 LiClO4/(EC+DMC)(1∶1) come from the special interaction between HF and LiClO4. The interaction occurred in the electrolyte promotes the build-up of effective solid electrolyte interface(SEI) film on the electrode surface during the first charging process. With the protection of the SEI film, the structural stability of the cathode material can be achieved and the electrochemical properties of the electrode can thus be enhanced. However, thick SEI film formed on the electrode surface resulted from high concentration of HF in the electrolyte leads to high interface resistance and thus decrease the electrochemical properties of spinel LiMn2O4.更多还原