Selective sulfur conversion with surface engineering of electrocatalysts in a lithium-sulfur battery  

作　　者：Yuejin Zhu Yinze Zuo Xuechao Jiao Revanasiddappa Manjunatha Ejikeme Raphael Ezeigwe Wei Yan Jiujun Zhang 

机构地区：[1]Institute for Sustainable Energy,College of Sciences,Shanghai University,Shanghai,PR China [2]College of Materials Science and Engineering,Fuzhou University,Fuzhou,PR China

出　　处：《Carbon Energy》2023年第2期72-84,共13页碳能源（英文）

基　　金：National Nature Science Foundation of China,Grant/Award Number:21908124。

摘　　要：The sluggish kinetics of multiphase sulfur conversion with homogeneous and heterogeneous electrochemical processes,causing the“shuttle effect”of soluble polysulfide species(PSs),is the challenges in terms of lithium-sulfur batteries(LSBs).In this paper,a Mn_(3)O_(4-x) catalyst,which has much higher activity for heterogeneous reactions than for homogeneous reactions(namely,preferentialactivity catalysts),is designed by surface engineering with rational oxygen vacancies.Due to the rational design of the electronic structure,the Mn_(3)O_(4-x) catalyst prefers to accelerate the conversion of Li2S4 into Li_(2)S_(2)/Li_(2)S and optimize Li_(2)S deposition,reducing the accumulation of PSs and thus suppressing the“shuttle effect.”Both density functional theory calculations and in situ X-ray diffraction measurements are used to probe the catalytic mechanism and identify the reaction intermediates of MnS and Li_(y)Mn_(z)O_(4-x) for fundamental understanding.The cell with Mn_(3)O_(4-x) delivers an ultralow attenuation rate of 0.028% per cycle over 2000 cycles at 2.5 C.Even with sulfur loadings of 4.93 and 7.10mg cm^(-2) in a lean electrolyte(8.4μL mg s^(-1)),the cell still shows an initial areal capacity of 7.3mAh cm^(-2).This study may provide a new way to develop preferential-activity heterogeneous-reaction catalysts to suppress the“shuttle effect”of the soluble PSs generated during the redox process of LSBs.

关 键 词：electrochemical kinetics heterogeneous catalysis lithium-sulfur batteries Mn3O4-x-catalyzed separator surface engineering 

分 类 号：O64[理学—物理化学]