层层自组装MoS_2多晶片增强锂硫电池性能（英文）  

Edge-rich MoS_2 nanosheets for high performance self-supporting Li-S batteries

作　　者：姚琳 周玲 李世雄[1] 李晓敏 何凯 何青泉[2] 宰建陶[1] 任奇志[1] 钱雪峰[1] YAO Lin;ZHOU Ling;LI Shixiong;LI Xiaomin;HE Kai;HE Qingquan;ZAI Jiantao;REN Qizhi;QIAN Xuefeng(School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China)

机构地区：[1]上海交通大学化学化工学院,上海200240 [2]上海大学环境与工程学院,上海200444

出　　处：《储能科学与技术》2019年第3期523-531,共9页Energy Storage Science and Technology

基　　金：National Natural Science Foundation of China(21771124,21673273 and 21371120);National Basic Research Program of China(2014CB239702);Science and Technology Commission of Shanghai Municipality(17ZR1441200,18230743400);Shanghai Rising-Star Program(18QA1402400);Scientific Innovation Talent of Henan Province(174200510017);China Postdoctoral Science Foundation(2017M611529 and 2017M621445)

摘　　要：提高硫的电化学活性和抑制多硫离子的溶解是提高锂硫电池性能的关键问题。层状二维金属硫化物的边缘位点相对于平面位点具有更强的吸附多硫离子的能力。然而利用液相法控制合成具有丰富边缘位点的层状二维过渡金属硫化物材料仍是一个挑战。本文以碳布作为导电基体,设计生长了由小尺寸单层S-Mo-S单元通过层层自组装而成的MoS_2多晶纳米片(V-MoS_2/CC)。探究了该复合材料作为活性物质S载体时对锂硫电池倍率性能和循环稳定性的影响。垂直生长的MoS_2纳米片暴露较多的S-Mo-S层边缘活性位点,不仅可以使得随后负载的硫单质的尺寸保持在纳米级(5~10 nm),而且对多硫化锂的催化转化及抑制溶解具有一定程度的促进作用。同时,基底材料碳布的存在使得电极材料无需添加导电剂和黏结剂且提高了整体导电性。使用V-MoS_2/CC@S复合材料组装而成的半电池,在1 C和2 C下循环400和800圈后比容量维持在857 mA?h/g和579 mA?h/g。Despite the high theoretical energy density and specific capacity, the practical application of Li-S battery is still impeded because of the low electrical conductivity of sulfur and the dissolution of lithium polysulfides in electrolyte. Edge sites of 2D layered transition metal dichalcogenides have been show advantages than in-plane sites on preventing the shuttling effects of polysulfides. While the synthesis of 3D hierarchical MoS2 structures with abundant active edge sites is still a challenge. Herein, vertically aligned MoS2 nanosheets with richly exposed (002) plane edges on the carbon cloth were fabricated via hydrothermal process and served as the host of sulfur to improve its electrochemical performance. Besides the carbon cloth as ideal supporting material to facilitate electron/ion transport, edge-rich layered MoS2 nanosheets with abundant dangling Mo-S bonds can localized the size of sulfur particles to 5-10 nm, which results a high utilization of active substances (~1174 mA·h·g^-1 at 0.1 C) and improve the reversibility and polysulfide redox kinetics. Furthermore, the edge sites have strong rules to absorb and catalyze the conversion of polysulfides. Therefore, the self-supporting cathode can deliver a specific discharge capacity (based on sulfur) of 857 mA·h·g^-1 at 1 C after 400 cycles and 579 mA·h·g^-1 at 2 C after 800 cycles.

关 键 词：锂硫电池 边缘位点 催化转化 自支撑 

分 类 号：TM911[电气工程—电力电子与电力传动]