Concurrent hetero-/homo-geneous electrocatalysts to bi-phasically mediate sulfur species for lithium-sulfur batteries  

作　　者：Rui-Bo LingHu Jin-Xiu Chen Jin-Hao Zhang Bo-Quan Li Qing-Shan Fu Gulnur Kalimuldina Geng-Zhi Sun Yunhu Han Long Kong 

机构地区：[1]Xi’an Institute of Flexible Electronics(IFE),Northwestern Polytechnical University,Xi’an 710129,Shaanxi,China [2]Institute of Advanced Materials,Nanjing Tech University,Nanjing 211816,Jiangsu,China [3]Advanced Research Institute of Multidisciplinary Science,Beijing Institute of Technology,Beijing 100081,China [4]Department of Mechanical and Aerospace Engineering,School of Engineering and Digital Sciences,Nazarbayev University,Kabanbay Batyr Ave.53,Astana 010000,Kazakhstan

出　　处：《Journal of Energy Chemistry》2024年第6期663-668,I0016,共7页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(22379121);Shenzhen Foundation Research Program(JCYJ20220530112812028);Fundamental Research Funds for the Central Universities(G2022KY0606);Zhejiang Province Key Laboratory of Flexible Electronics Open Fund(2023FE005)。

摘　　要：Expediting redox kinetics of sulfur species on conductive scaffolds with limited charge accessible surface is considered as an imperative approach to realize energy-dense and power-intensive lithium-sulfur(Li-S)batteries.In this work,the concept of concurrent hetero-/homo-geneous electrocatalysts is proposed to simultaneously mediate liquid-solid conversion of lithium polysulfides(LiPSs)and solid lithium disulfide/sulfide(Li_(2)S_(2)/Li_(2)S)propagation,the latter of which suffers from sluggish reduction kinetics due to buried conductive scaffold surface by extensive deposition of Li_(2)S_(2)/Li_(2)S.The selected model material to verify this concept is a two-in-one catalyst:carbon nanotube(CNT)scaffold supported iron-cobalt(Fe-Co)alloy nanoparticles and partially carbonized selenium(C-Se)component.The Fe-Co alloy serves as a heterogeneous electrocatalyst to seed Li_(2)S_(2)/Li_(2)S through sulphifilic active sites,while the C-Se sustainably releases soluble lithium polyselenides and functions as a homogeneous electrocatalyst to propagate Li_(2)S_(2)/Li_(2)S via solution pathways.Such bi-phasic mediation of the sulfur species benefits reduction kinetics of LiPS conversion,especially for the massive Li_(2)S_(2)/Li_(2)S growth scenario by affording an additional solution directed route in case of conductive surface being largely buried.This strategy endows the Li-S batteries with improved cycling stability(836 mA h g^(-1)after 180 cycles),rate capability(547 mA h g^(-1)at 4 C)and high sulfur loading superiority(2.96 mA h cm^(-2)at 2.4 mg cm^(-2)).This work hopes to enlighten the employment of bi-phasic electrocatalysts to dictate liquid-solid transformation of intermediates for conversion chemistry batteries.

关 键 词：Lithium-sulfur batteries Electrocatalysis Lithium polysulfides Sulfur cathode Energy density 

分 类 号：TQ426[化学工程] TM912[电气工程—电力电子与电力传动]