理论揭示锂硫电池第二放电平台的主要液固相转换机制
Theoretically revealing the major liquid-to-solid phase conversion mechanism of the second plateau in lithium-sulfur batteries
张洪毅 1薛红涛 1魏承东 1孙杰 1许健 1汤富领1
作者信息
- 1. School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China
- 折叠
摘要
锂硫电池因其高理论能量密度、环境友好和低廉的成本而被认为是前景广阔的新型储能设备,但在放电后半程中缓慢的还原动力学严重阻碍其实际应用.虽然各种先进的正极材料改善了反应动力学,但硫还原反应(SRR)的复杂机理给提高锂硫电池性能设下许多障碍.深入研究其电催化机理是指导阴极材料设计和应用的重要环节.本文将揭示从Li2S3向Li2S2/Li2S的转化机制,即揭示从液相多硫化物到固相多硫化物的硫还原反应.以Ti、V、Fe、Co和Ni单原子催化剂为正极催化材料,建立基于密度泛函理论计算的电催化模型.中间产物*LiS、*LiS2被用作预测反应路径、速率决定步骤和过电位的描述因子.这项工作解释了放电后期可溶多硫化物向不溶多硫化物的转化机理,为设计先进的高性能锂硫电池电催化剂提供了指导.
Abstract
Lithium-sulfur(Li-S)batteries are considered promising new energy storage devices due to their high the-oretical energy density,environmental friendliness,and low cost.The sluggish reduction kinetics during the second half of the discharge hampers the practical applications of Li-S bat-teries.Although the reaction kinetics has been improved by various advanced cathode materials,the complex mechanism of the sulfur reduction reaction(SRR)leaves many obstacles to guide people in improving Li-S battery performances.An in-depth investigation of its electrocatalytic mechanism is an vital link to guide the design and application of cathode materials.Herein,the chemical mechanism from Li2S3 to Li2S2/Li2S will be revealed,which also means that SRR from liquid-phase polysulfides to solid-phase polysulfides will be unveiled.An electrocatalytic model based on systematic density-functional theory calculations was developed using single-atom catalysts involving Ti,V,Fe,Co,and Ni as the cathodic catalytic ma-terials.Intermediate products*LiS and*LiS2 are used as de-scriptors to predict reaction pathways,rate-determining steps and overpotentials.This work explains the conversion me-chanism of soluble to insoluble polysulfides at the late dis-charge stage and guides for the design of advanced high-performance lithium-sulfur battery electrocatalysts.
关键词
density functional theory/electrocatalytic model/Li2S3 conversion/lithium-sulfur battery/single atom catalysisKey words
density functional theory/electrocatalytic model/Li2S3 conversion/lithium-sulfur battery/single atom catalysis引用本文复制引用
基金项目
Major Science and Technology Project of Gansu Province(22ZD6GA008)
National Natural Science Foundation of China(11764027)
National Natural Science Foundation of China(12204210)
出版年
2024
NETL
NSTL
万方数据