高电压锂金属二次电池用离子型局部高浓电解液

Ionic-type localized-high concentration electrolytes for high-voltage lithium metal secondary battery

基于有机离子盐(离子液体或离子塑性晶体)的离子型局部高浓电解液(iLHCEs)可用于高性能锂金属二次电池,但Li+传导能力、与锂金属负极和高电压正极的兼容性等需优化。使用有机离子塑性晶体N-乙基-N-甲基吡咯烷鎓双(三氟甲基磺酰)亚胺盐(Pyr12TFSI)构筑iLHCEs,形成的[Li^(+)][FSI-][TFSI-][Pyr12^(+)]紧密离子簇可衍生稳定的固体电解质相界面(SEI),抑制副反应发生与锂枝晶生成,使锂沉积/剥离的库仑效率高达99.03%。使用基于Pyr12TFSI的iLHCEs的高电压Li|LiCoO_(2)(4.5 V)及Li|LiNi_(0.5)Mn_(1.5)O_(4)(5.0 V)电池,具有较高的首次库仑效率、长循环稳定性及理想的倍率性能。

Ionic-type localized high concentration electrolytes(iLHCEs)based on organic ionic salts(ionic liquids or ionic plastic crystals)could be used for high performance lithium metal secondary batteries.Nevertheless,the Li+conductivity,lithium metal anode and high-voltage cathode compatibility still remained to be optimized.The iLHCEs were constructed by using an organic ionic plastic crystal N-ethyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide(Pyr12TFSI).The formed[Li^(+)][FSI-][TFSI-][Pyr12^(+)]compact ion clusters could derive a stable solid electrolyte phase interface(SEI)to inhibit the occurrence of side reactions and the formation of lithium dendrites,making the lithium deposition/stripping Coulombic efficiency up to 99.03%.The high-voltage Li|LiCoO_(2)(4.5 V)and Li|LiNi_(0.5)Mn_(1.5)O_(4)(5.0 V)battery using Pyr12TFSI-based iLHCEs had higher Coulombic efficiency,long-term cycle stability and fine rate capability.