聚阴离子单离子导体凝胶电解质的制备及其在锂离子电池中的应用

Preparation of Single-ion Conducting Polyanionic Gel Electrolyte and Its Application on Lithium-ion Batteries

以2-丙烯酰胺-2-甲基丙磺酸(AMPS)与Li_(2)CO_(3)反应制得AMPSLi单体,以(聚偏氟乙烯-六氟丙烯)共聚物(PVDF-HFP)为基膜条件进行原位聚合,加入乙二醇二甲醚(DME),1,3-二氧戊烷(DOL)作为增塑剂,制备了一种聚阴离子单离子导体凝胶电解质。采用电化学工作站进行电化学稳定窗口与迁移数表征。结果表明:单离子导体凝胶电解质具有2~4.5 V的宽电化学稳定窗口以及高达0.74的锂离子迁移数。采用磷酸铁锂(LFP)作正极,金属锂作负极,PVDF-HFP-PAMPSLi单离子导体作为电解质组装电池。在不加入锂盐时,电池在2 C电流密度下具有125 mAh·g^(-1)的高比容量和超过500次的循环次数;在5 C的高电流密度下具有100 mAh·g^(-1)的比容量与超过300次的稳定循环能力,并保持接近100%的稳定库伦效率。

AMPSLi monomer was prepared by the reaction of AMPS and Li_(2)CO_(3),and polymerized in(poly vinylidenefluoride-hexafluoro propylene)copolymer(PVDF-HFP)film.Subsequently,the polyanionic single-ion conductor gel electrolyte was prepared with dimethoxymethane(DME)and 1,3-dioxolane(DOL)as plasticizer.The electrochemical stability window and ion transference number were characterized by electrochemical workstation.The results show that the polyanionic gel electrolyte owns a wide electrochemical stability window of 2~4.5 V and a high transference number of 0.74.When assembled with LFP as cathode electrode and Li metal as anode electrode,the battery can provide an excellent reversible specific capacity of 125 mAh·g^(-1) even after 500 cycles at a high current density of 2 C,and a specific capacity of 100 mAh·g^(-1) at 5 C for more than 300 stable cycles.