Acta Phys. -Chim. Sin. ›› 2023, Vol. 39 ›› Issue (5): 2212005.doi: 10.3866/PKU.WHXB202212005

• REVIEW • Previous Articles     Next Articles

Advances in Single Metal Atom Catalysts Enhancing Kinetics of Sulfur Cathode

Jingjing Wang1,2, Guiqiang Cao1,2, Ruixian Duan1,2, Xiangyang Li3,*(), Xifei Li1,2,*()   

  1. 1 Institute of Advanced Electrochemical Energy, School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, China
    2 Engineering Research Center of Conducting Materials and Composite Technology, Ministry of Education, Xi'an 710048, China
    3 Science and Technology on Electromechanical Dynamic Control Laboratory, Xi'an Institute of Electromechanical Information Technology, Xi'an 710065, China
  • Received:2022-12-03 Accepted:2023-01-02 Published:2023-02-13
  • Contact: Xiangyang Li, Xifei Li E-mail:liyang2039@163.com;xfli@xaut.edu.cn
  • Supported by:
    the Scientific Research Program Funded by Education Department of Shaanxi Provincial Government(22JP056)

Abstract:

Sulfur has been considered as an ideal cathode of lithium sulfur batteries (LSBs) owing to its high theoretical energy density (2600 Wh∙Kg-1), excellent discharge capacity (1672 mAh∙g-1), and low cost. During sulfur reduction and oxidation processes, nevertheless, the sluggish redox reaction kinetics of the sulfur cathode and severe shuttle effect of soluble lithium polysulfides intermediates significantly result in poor battery performance. It has been demonstrated that a sulfur host with high adsorption energy and excellent catalytic activity/selectivity can effectively enhance the cycle stability and rate capability of LSBs. As a result, a variety of hosts, such as metal compounds, heterojunctions, defect matrices, and single metal atom catalysts, have been widely developed. Interestingly, single metal atom catalysts with a unique electronic structure, low metal content, theoretical 100% atom utilization efficiency, and high catalytic performance can effectively promote the conversion of different lithium polysulfides intermediates and provide abundant absorption sites for sulfur-contained species, thereby optimizing the redox reaction kinetics of the sulfur cathode and shuttle behavior of the soluble lithium polysulfides. Various single metal atom catalysts, mainly including iron, cobalt, nickel, zinc, tungsten, vanadium, molybdenum, and manganese, have been developed via atomic bonding, spatial confinement, and defect engineering strategies to solve the key challenges of sulfur cathode since single metal atom catalysts were for the first time to be utilized as catalytic agents for LSBs. In this review, the interaction among support materials in single metal atom catalysts, atomically dispersed metal catalytic sites, and the sulfur cathode were addressed in detail, providing a basis for the development of high-performance single metal atom catalysts. Furthermore, advanced characterization techniques such as in situ Raman spectroscopy, X-ray absorption spectroscopy, cyclic voltammograms, and electrochemical impedance spectroscopy, were employed to investigate the catalytic effect of single metal atom catalysts. Notably, the effects of the coordination environment on the catalytic activity and selectivity of single metal atom catalysts were systematically discussed. Simultaneously, the catalytic mechanism of single metal atom catalysts with different metal/nonmetallic atoms and coordination configurations was elucidated using theoretical calculations. In addition, some significant challenges of single metal atom catalyst in LSBs were proposed. It is believed that this review will provide a novel insight into the optimization of atomic catalysts with high activity and catalytic selectivity toward long-lifespan LSBs.

Key words: Sulfur cathode, Reaction kinetics, Single metal atom catalyst, Polysulfide conversion, Lithium sulfur battery