To effectively alleviate the severe shuttle effect and delayed redox kinetics of lithium–sulfur batteries, CoWO4−x/CNT composites with different oxygen vacancy concentrations were prepared. The p–d orbital hybridization caused by oxygen vacancy enhances the bidirectional sulfur conversion, and provides valuable insights for the development of highly active catalysts for lithium–sulfur batteries.
Abstract:
Lithium–sulfur batteries (LSBs) have garnered significant concern as materials with high energy density for energy storage. Nevertheless, their severe shuttle effect and delayed redox kinetics limit their practical application. Herein, a strategy based on the regulation of oxygen vacancy concentration in CoWO4 has been proposed to accelerate polysulfide kinetics. Experiments and density functional theory calculations reveal that catalytic materials with the appropriate number of oxygen vacancies (CWO-M) have moderate adsorption energy and optimal catalytic capacity for polysulfides due to strong p–d orbital hybridization. More importantly, CWO-M not only accelerates the reduction of sulfur during discharge but also significantly accelerates the oxidation of Li2S during charging, showing a favorable bidirectional catalytic effect. Benefiting from these unique advantages, the CWO-M/S-based battery exhibits an excellent rate performance of 768 mAh g−1 at 2 C and a capacity retention of 91.1% after 100 cycles at 0.2 C. Stable cycling performance with a high capacity of nearly 4 mAh cm−2 was achieved even after 100 cycles at a high sulfur loading of 8.02 mg cm−2 and a low electrolyte/sulfur (E/S) ratio of 8 µL mg S−1. This work provides significant insights into bidirectional catalysts by modulating the oxygen vacancy concentration for application in LSBs.
Author list:
Yan Chen†, Dan Li†, Yufang Chen†, Xingqiao Wu*, Manfang Chen*, Yuchao Du, Keyang Fu, Hao Yuan, Shuangying Wei, Xianyou Wang, Hongbo Shu*
How to cite:
Y. Chen, D. Li, Y. Chen, X. Wu, M. Chen, Y. Du, K. Fu, H. Yuan, S. Wei, X. Wang, H. Shu, Exploration 2025, 20240362.
https://doi.org/10.1002/EXP.20240362