基于EDOT原位包覆碳硫复合物锂硫电池的正极设计及其性能研究  

Cathode design and performance study of lithium-sulfur battery based on EDOT in-situ coated carbon sulfur composites

作　　者：贾洪声 赵兴 王钊 魏祎 李海波[1] JIA Hong-sheng;ZHAO Xing;WANG Zhao;WEI Yi;LI Hai-bo(College of Physics,Jilin Normal University,Siping 136000,China)

机构地区：[1]吉林师范大学物理学院,吉林四平136000

出　　处：《吉林师范大学学报（自然科学版）》2022年第1期43-49,共7页Journal of Jilin Normal University:Natural Science Edition

基　　金：国家自然科学基金项目(21978110);吉林省自然科学基金项目(20200201236JC)。

摘　　要：锂硫电池被认为是最有前途的高能量密度储能系统,但充电过程中多聚硫化物的溶解限制了活性材料的利用率和循环稳定性,影响了锂硫电池的实际应用.通过电化学聚合电解质中所含的3,4-乙烯二氧噻吩(EDOT)单体,使其在正极碳硫复合物表面原位形成聚乙烯二氧噻吩包覆层.在电池内部原位形成包覆层,可以增加电解液与活性物质的浸润性,提高Li+电导率,从而增加活性物质利用率.通过极性-极性键吸附多硫化物,抑制穿梭效应,从而提高循环稳定性.实验结果显示,添加50 mmol/L EDOT的锂硫电池的初始放电比容量为1155 mA·h/g,200次循环比容量仍高达770 mA·h/g,优于未添加EDOT的锂硫电池.Lithium sulfur battery is considered to be the most promising high energy density energy storage system,but the dissolution of polysulfides during charging limits the utilization and cycle stability of active materials,which affects the practical application of lithium sulfur battery.A polyethylene dioxythiophene coating was formed on the surface of the positive carbon sulfur composites by using the 3,4-ethylene dioxythiophene(EDOT)monomer contained in the electrochemical polyelectrolyte.Forming a coating layer in situ inside the battery can increase the wettability of electrolyte and active substances,improve Li+conductivity,and increase the utilization of active substances.Polysulfides are adsorbed through polar polar bonds to inhibit the shuttle effect,so as to improve the cycle stability.The experimental results show that the initial discharge specific capacity of lithium sulfur battery with 50 mmol/L EDOT is 1155 mA·h/g,and the specific capacity of 200 cycles is still as high as 770 mA·h/g,which is better than that of lithium sulfur battery without EDOT.

关 键 词：锂硫电池 导电聚合物 原位包覆 飞梭效应 

分 类 号：TM912[电气工程—电力电子与电力传动]