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电化学(中英文) ›› 2020, Vol. 26 ›› Issue (5): 694-715.  doi: 10.13208/j.electrochem.200654

• 综述 • 上一篇    下一篇

锂硫电池硫正极催化转换反应的研究进展

邵钦君1,2, 陈剑1,*()   

  1. 1.中国科学院大连化学物理研究所,辽宁 大连 116023
    2.中国科学院大学,北京 100049
  • 收稿日期:2020-08-03 修回日期:2020-09-08 出版日期:2020-10-28 发布日期:2020-10-28
  • 通讯作者: 陈剑 E-mail:chenjian@dicp.ac.cn
  • 基金资助:
    中国科学院战略性先导科技专项(XDA17020404);国家重点项目研发计划(2016YFB0100100)

Research Progress of Sulfur Cathode Catalytic Conversions for Lithium-Sulfur Batteries

SHAO Qin-jun1,2, CHEN Jian1,*()   

  1. 1. Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, Liaoning, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-08-03 Revised:2020-09-08 Published:2020-10-28 Online:2020-10-28
  • Contact: CHEN Jian E-mail:chenjian@dicp.ac.cn

摘要:

单质硫作为电池的正极材料,其电化学过程历经多个步骤,完全放电生成最终产物是一个2电子反应. 低阶多硫化锂的生成需克服一定的能垒,且由Li2S2得到一个电子还原生成Li2S的反应是速控步骤. 硫正极的反应动力学是决定锂硫电池电化学性能,如比能量、比功率、低温性能等的关键因素. 提高速控步骤的反应动力学还能加速可溶性多硫化锂Li2S4向不溶性Li2S2和Li2S的转化,有利于减缓或消除多硫化锂的“穿梭效应”. 近年,已有大量的过渡金属氧化物、硫化物、碳化物、氮化物、磷化物,单原子催化剂和氧化还原电子中继体等被应用于催化硫正极反应,提高了电极的电化学性能和循环稳定性. 但是,目前详细的催化反应机制尚不完全清晰. 本文重点综述了这些化合物在硫正极反应中的作用机制,总结了近年来的研究进展,并对硫正极催化转换反应的研究和发展进行了展望.

关键词: 锂硫电池, 硫正极, 催化转换

Abstract:

The electrochemical reduction of sulfur (S) takes place through multistep reactions when S is used as a cathode material. The complete discharge of S to form final product lithium sulfide (Li2S) is a two-electron reaction. The formation of low-order lithium polysulfides (LiPS) needs to overcome certain energy barriers. And the reduction of Li2S2 to Li2S is the rate-limited step. The reaction kinetic of sulfur cathode is the critical key to determine the electrochemical performance of Li-S batteries, such as specific energy, specific power and low temperature performance, etc. Accelerating the rate-limited step kinetics of sulfur cathodes can promote the conversion of soluble Li2S4 to insoluble Li2S2/Li2S, contributing to suppressed or eliminated “shuttle effect”. Recently, there are lots of transition metal oxides, sulfides, carbides, nitrides, phosphate, single atoms and redox electron mediators being applied in the preparations of sulfur cathodes, which improve the electrochemical performances and cycle stabilities. However, detailed mechanism of catalytic reaction is not completely clear. This review focuses on the functional and catalytic mechanisms of those metal compounds towards polysulfides, summarizes the recent research progress, and prospects the development and ongoing research of sulfur cathodes.

Key words: lithium-sulfur batteries, sulfur cathodes, catalytic conversions

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