CoS 2 @SC modified separator for high-performance lithium-sulfur batteries: suppression of polysulfide shuttling

ABSTRACTDue to their high energy density and cost-effective electrode materials, lithium sulfur batteries (LSBs) have been considered as one promising candidate of energy devices. However, the practical application is impeded by the shuttle effect of lithium polysulfides and slow redox kinetics of electrode. Here, we report a successful synthesis of CoS2@SC composite material via in-situ growth and sulfuration pyrolysis method and prepared CoS2@SC modified separator. The carbon matrix derived from sucrose carbonization with a porous structure promotes the uniform distribution of active adsorption sites. According to Lewis acid–base interaction, CoS2@SC separator exhibits strong chemisorption of lithium polysulfides, reducing the loss of active material during cycling. Furthermore, the enhanced wettability of the CoS2@SC separator with the electrolyte accelerates the ion transfer, improving the reaction kinetics. Compared with the blank separator, the cell with CoS2@SC separator has an initial specific capacity of 1135.5 mAh g−1 and notably, the capacity decay rate of the modified battery is only 0.052% per cycle after 800 long cycles at 0.5 C. This unique attribute ensures enhanced stability and durability of the battery system. Consequently, LSBs with the CoS2@SC separator exhibit an improved electrochemical performance.KEYWORDS: Lithium sulfur batteriesmodified separatorshuttle effectchemical adsorptionmetal sulfide AcknowledgementsThis work is financially supported by the National Natural Science Foundation of China, China (No. 21676148), and the Fundamental Research Funds for the Central Universities, China (No. 30918012202)Disclosure statementWenju Wang reports financial support was provided by National Natural Science Foundation ofl China. Wenju Wang reports financial support was provided by Fundamental Research Funds for the Central Universities.Supplementary materialSupplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2023.2259836.Additional informationFundingThis work was supported by the Fundamental Research Funds for the Central Universities [30918012202]; National Natural Science Foundation of China [21676148].Notes on contributorsYongan CaoYongan Cao is the student of Nanjing University of Science and Technology.Jiyuan YouJiyuan You is the student of Nanjing University of Science and Technology.Xuefei LiuXuefei Liu is the staff of the Fourth Construction Co, LTD of China Construction Eighth Engineering Division.Xiaoqian HaoXiaoqian Hao is the student of Nanjing University of Science and Technology.Qiao WuQiao Wu is the student of Nanjing University of Science and Technology.Bo ZhangBo Zhang is the student of Nanjing University of Science and Technology.Zhiming XuZhiming Xu is the student of Nanjing University of Science and Technology.Liwei DengLiwei Deng is the student of Nanjing University of Science and Technology.Wenju WangWenju Wang is the teacher of Nanjing University of Science and Technology.Yuqian LiYuqian Li is the teacher of Nanjing University of Science and Technology.