金属配位聚合物衍生的MoS_(2)在锂硫电池多硫化物催化转化中的应用  

Metal-Organic Coordination Polymer-Derived MoS2 Catalysts for High Efficient Polysulfides Conversion in Lithium-Sulfur Batteries

作　　者：程孟浩 颜睿 李爽 程冲[1] 赵长生[1] Menghao Cheng;Rui Yan;Shuang Li;Chong Cheng;Changsheng Zhao(College of Polymer Science and Engineering,State Key Laboratory of Polymer Materials Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学高分子科学与工程学院高分子材料工程国家重点实验室,四川成都610065

出　　处：《高分子材料科学与工程》2022年第9期138-145,共8页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(52161145402,51903178)。

摘　　要：锂硫电池在充放电过程中存在多硫化物的氧化还原反应动力学缓慢的现象,导致多硫化锂穿梭效应严重、电池容量衰减等问题。因此,需要高性能的电催化剂来加速锂硫电池中多硫化物的可逆转化。文中以金属配位聚合物为前驱体合成了多孔碳球负载的钴掺杂二硫化钼(pcs-Co@MoS_(2))材料作为多硫化物催化转化的催化剂,极大地提升了锂硫电池的循环性能。以pcs-Co@MoS_(2)为电极材料的电池在充电和放电过程都展现了较低的Tafel斜率(55.47 mV/dec和27.57 mV/dec),表明其较快的反应动力学。恒压放电测试表明,pcs-Co@MoS_(2)组装的电池具有较高的Li_(2)S沉积容量(155.07 mAh/g),体现出其更高的硫利用率。0.5 C倍率下的充放电测试时,pcs-Co@MoS_(2)的初始放电比容量达到了796 mAh/g;在1 C高倍率的循环测试中,电池容量在200圈后保持率为80%,每圈衰减率仅为0.09%。The redox reaction kinetics of polysulfides conversion was sluggish during the charging/discharging process,which resulted in serious shuttle effect and capacity decay of lithium-sulfur batteries.Therefore,high performance electrocatalysts for accelerating the polysulfides conversion process were highly desired.Herin,porous carbon spheres loaded with Co-doped molybdenum disulfide(pcs-Co@MoS_(2))were synthesized as high performance polysulfides conversion catalysts by using metal-organic coordination polymers as precursors.The lower Tafel slopes(55.47 mV/dec and 27.57 mV/dec)of the batteries consisting of pcs-Co@MoS_(2) are observed during charging and discharging process,indicating a fast reaction kinetics.Potentiostatic discharge test shows that batteries with pcs Co@MoS_(2) have a higher deposition capacity of Li_(2)S(155.07 mAh/g),which reflects the high sulfur utilization.The cycling performance as assembled lithium sulfur batteries is greatly improved in terms of the initial discharge specific capacity at the rate of 0.5 C(796 mAh/g)measured by charge-discharge test.Most importantly,the capacity retention of the battery is up to 80%and the decay rate per cycle is only 0.09%after 200 cycles at the charge/discharge rate of 1 C during cycling test.

关 键 词：金属配位聚合物 锂硫电池 多硫化物 催化转化 二硫化钼 

分 类 号：TM912[电气工程—电力电子与电力传动]