文献类型：期刊文献

英文题名：Unique electrochemical behavior of heterocyclic selenium-sulfur cathode materials in ether-based electrolytes for rechargeable lithium batteries

作者：Wei, Yanju[1];Tao, Yingqing[1];Kong, Zhenkai[1];Liu, Lei[1];Wang, Jitong[1];Qiao, Wenming[1,2];Ling, Licheng[1,2];Long, Donghui[1,2]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Key Lab Specially Funct Polymer Mat & Related Tec, Shanghai 200237, Peoples R China

年份：2016

卷号：5

起止页码：171

外文期刊名：ENERGY STORAGE MATERIALS

收录：EI(收录号：20192907206287);WOS:【ESCI(收录号:WOS:000399335700015)】；

基金：This work was supported by China's Ministry of Science and Technology (MOST) (2014CB239702) and National Natural Science Foundation of China (Nos. 51302083,51172071 and 51272077), and Fundamental Research Funds for the Central Universities and Shanghai Rising-Star Program (15QA1401300).

语种：英文

外文关键词：SexSy cathodes; Mesoporous carbon microsphere; Se-S bonds; Ether-based electrolyte; Rechargeable lithium batteries

摘要：Mixed chalcogenide systems represent a new class of promising cathode materials for high performance rechargeable lithium batteries. Among them, heterocyclic selenium-sulfur (SexSy) cathodes, coupling the good conductivity of Se and high capacity of S, have attracted great attention in recent years. However, further research is still needed to better understand the lithiation/delithiation process of SexSy cathodes in ether-based electrolytes. Herein, SexSy-based composites with covalent Se-S bonds were prepared by infiltrating various proportions of S and Se powders into the mesoporous carbon microsphere (MCM) host at 500 degrees C in vacuum. As cathodes for rechargeable lithium batteries, SexSy/MCM composites exhibit unique electrochemical behavior rather than a simple hybrid of Li-S and Li-Se batteries in ether-based electrolytes. The Se-S bonds in SexSy/MCM could anchor S during cycling, and effectively reduce the formation of long-chain polysulfides. As a result, the SexSy/MCM cathodes demonstrate superior overall electrochemical performance than Se/MCM or S/MCM. Moreover, Se/S ratio could also affect the electrochemical behavior of SexSy/MCM composites. The optimal Se2S5/MCM cathode delivers the best performance with a high reversible capacity of 796.4 mAh g(-1) at 0.5 C over 100 cycles, and good rate capability of 688.8 mAh g(-1) at 5 C. Especially, a superior coulombic efficiency of similar to 100% is achieved without addition of LiNO3. This work could help us to better understand the inherent synergistic mechanism behind SexSy cathodes for high performance rechargeable lithium batteries in ether-based electrolytes. (C) 2016 Elsevier B.V. All rights reserved.