溶剂化离子液体修饰的高性能聚环氧乙烷基固态电解质  

High-performance poly(ethylene oxide)-based solid-state electrolytes modified with solvated ionic liquid

作　　者：邱安 王子涵 董鑫 董金超[1,2] 蒋玉雄 李剑锋 QIU An;WANG Zihan;DONG Xin;DONG Jinchao;JIANG Yuxiong;LI Jianfeng(College of Energy,Xiamen University,Xiamen 361102,China;State Key Laboratory of Physical Chemistry of Solid Surfaces,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China;Xiamen Gaorong Nanomaterial Science&Technology Co.,Ltd.,Xiamen 361021,China;Tan Kah Innovation Laboratory,Xiamen 361102,China)

机构地区：[1]厦门大学能源学院,福建厦门361102 [2]厦门大学化学化工学院,固体表面物理化学国家重点实验室,福建厦门361005 [3]厦门高容纳米新材料科技有限公司,福建厦门361021 [4]嘉庚创新实验室,福建厦门361102

出　　处：《厦门大学学报(自然科学版)》2025年第1期93-102,共10页Journal of Xiamen University:Natural Science

基　　金：国家重点研发计划(2019YFA0705402);国家自然科学基金(21925404,22021001);福建省高校产学研联合创新项目(2023H6029)。

摘　　要：[目的]针对聚环氧乙烷(PEO)基固态电解质存在高压稳定性差、锂离子迁移数和电导率低等问题,设计制备了一系列溶剂化离子液体[Li(G4)][FSI]修饰的PEO基固态电解质.[方法]引入溶剂化离子液体[Li(G4)][FSI]作为PEO基固态电解质的锂源和添加剂,运用各种谱学和电化学方法对固态电解质进行表征,并考察了[Li(G4)][FSI]含量对固态电解质的影响.[结果]当n(EO)∶n(Li)=20∶1时,与PEO-LiFSI-20∶1(PF-20)相比,制备的PEO-[Li(G4)][FSI]-20∶1(PGF-20)固态电解质的结晶度和机械强度未产生明显变化,在60℃下其锂离子电导率(0.44 mS/cm)和迁移数(0.253)明显提升.随着[Li(G4)][FSI]含量的增加,固态电解质的结晶度和机械性能未产生明显变化,其60℃下的锂离子电导率随之增加,而孔道直径和数量则呈先减小后增大的趋势,其中PGF-20的孔道直径最小、数量最少,且具有最低的对称电池过电位和最高的氧化电位.将PGF-20应用到Li‖LiFePO_(4)全固态电池,可以在60℃、0.5 C的条件下稳定循环100次,且容量保持率可达88.7%.[结论]溶剂化离子液体的引入使得固态电解质表面产生微米级的孔道结构,从而有利于锂离子的传输;适量引入溶剂化离子液体可生成富含LiF的稳定固态电解质界面,使其锂对称电池具有较低的过电位.本研究成功构筑基于溶剂化离子液体的高性能PEO基固态电解质,可为同类型固态电解质的开发提供借鉴.[Objective]As a cutting-edge innovation designed to enhance the safety and energy density of lithium-based batteries,all-solid-state battery technology has shown significant potential for development.Among these advancements,organic solid-state electrolytes based on poly(ethylene oxide)(PEO)offer promising applications in high-energy-density lithium-metal batteries due to their exceptional chemical stability and compatibility with lithium metal.However,PEO-based solid-state electrolytes face limitations in high-voltage stability,lithium-ion mobility,and conductivity,which significantly hinder their practical application.As a result,researchers are seeking simple and effective methods to improve the electrochemical performance of PEO-based solid-state electrolytes.Recently,ionic liquids,particularly solvated ionic liquids,have emerged as cost-effective and easily prepared materials in solid-state electrolyte,indicating their potential to enhance the performance of solid-state electrolytes.[Methods]In this study,the solvated ionic liquid[Li(G4)][FSI]was introduced as a lithium source and additive for PEO-based solid-state electrolytes.PEO-based solid electrolytes modified with[Li(G4)][FSI]were prepared using the solution casting method.Initially,tetraethylene glycol dimethyl ether(G4)and LiFSI were utilized as raw materials,resulting in the creation of the solvated ionic liquid[Li(G4)][FSI]through a 1∶1 mixing ratio of n(LiFSI)∶n(G4).Subsequently,PEO and[Li(G4)][FSI]/LiFSI were dissolved in acetonitrile at varying ratios of n(EO)∶n(Li)(x∶1,with x values of 16,18,20,22,24)to produce a solid-state electrolyte solution.This solution was then evenly spread within a polytetrafluoroethylene mold,and the solid-state electrolyte film was formed by evaporating the solvent under vacuum at 60℃.The solid-state electrolyte films were characterized using various spectroscopic and electrochemical methods.[Results]Scanning electron microscopy(SEM)images revealed that the incorporation of[Li(G4)][FSI]prompted the formatio

关 键 词：聚环氧乙烷基固态电解质 溶剂化离子液体 固态锂金属电池 锂离子电导率 锂离子迁移数 

分 类 号：O69[理学—化学] O646