【摘要】 采用电化学扫描隧道显微镜(EC-STM)研究锂盐存在时,1-乙基-3-甲基咪唑二(三氟甲基磺酰)亚胺(EMITFSI)在Au(111)上的界面行为.随电位负移,表面过程主要分为3个阶段:(1)溶解在离子液体中的恒量氧气约在2 V还原,并与锂盐生成锂氧化物的网状结构;(2)溶液中的微量水约在1.5 V还原,并与锂盐生成较致密的氢氧化锂表面膜层;(3)当电位负移至约0.85 V时,离子液体的分解、锂的欠电位沉积以及锂-金合晶的形成共同发生,形成大量导电性较差的簇状结构膜,相应于金电极上初始形成的SEI膜.研究工作对于理解电极/离子液体界面性质及离子液体中的SEI膜具有重要意义.更多还原

【Abstract】 We report an in situ scanning tunneling microscopic study of surface morphology changes in Au(111) electrode in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMITFSI) ionic liquid containing Li TFSI salt. The surface processes can be divided into three stages: In the first stage, a reduction wave of dissolved oxygen in the ionic liquid appears at approximately 2.0 V and a network structure covers the surface afterward; in the second stage at around 1.5 V, reduction of trace water is initiated and a surface film containing lithium hydroxide is formed; in the third stage, as potential is further decreased to0.85 V, decomposition of the EMITFSI ionic liquid occurs, which is accompanied by lithium underpotential deposition and Au–Li alloying. In this stage, the surface experiences significant morphological changes with formation of many clusters on the surface, and eventually becomes electronically less conductive. This unique surface film is understood to be the initial stage formation of a solid electrolyte interphase on gold,which may be a common feature in ionic liquids in the presence of lithium salt.更多还原