理论揭示锂硫电池第二放电平台的主要液固相转换机制

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中文摘要：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.

外文标题：Theoretically revealing the major liquid-to-solid phase conversion mechanism of the second plateau in lithium-sulfur batteries

外文摘要：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.

外文关键词：

density functional theoryelectrocatalytic modelLi2S3 conversionlithium-sulfur batterysingle atom catalysis

作者：

张洪毅、薛红涛、魏承东、孙杰、许健、汤富领

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作者单位：

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

关键词：

density functional theory electrocatalytic model Li2S3 conversion lithium-sulfur battery single atom catalysis

基金：

Major Science and Technology Project of Gansu ProvinceNational Natural Science Foundation of ChinaNational Natural Science Foundation of China

项目编号：

22ZD6GA0081176402712204210

出版年：

2024

DOI：

10.1007/s40843-024-2925-1

中国科学:材料科学(英文)

CSTPCD

ISSN：

年,卷(期)：2024.67(8)

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