Optimizing potassium polysulfides for high performance potassium-sulfur batteries

作者：Wanqing Song, Xinyi Yang, Tao Zhang, Zechuan Huang, Haozhi Wang, Jie Sun, Yunhua Xu, Jia Ding, Wenbin Hu · 发表于：Nature Communications · 年份：2024 · DOI：10.1038/s41467-024-45405-w · 被引用次数：69 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Thermal Expansion and Ionic Conductivity

Abstract Potassium-sulfur batteries attract tremendous attention as high-energy and low-cost energy storage system, but achieving high utilization and long-term cycling of sulfur remains challenging. Here we show a strategy of optimizing potassium polysulfides for building high-performance potassium-sulfur batteries. We design the composite of tungsten single atom and tungsten carbide possessing potassium polysulfide migration/conversion bi-functionality by theoretical screening. We create two ligand environments for tungsten in the metal-organic framework, which respectively transmute into tungsten single atom and tungsten carbide nanocrystals during pyrolysis. Tungsten carbide provide catalytic sites for potassium polysulfides conversion, while tungsten single atoms facilitate sulfides migration thereby significantly alleviating the insulating sulfides accumulation and the associated catalytic poisoning. Resultantly, highly efficient potassium-sulfur electrochemistry is achieved under high-rate and long-cycling conditions. The batteries deliver 89.8% sulfur utilization (1504 mAh g −1 ), superior rate capability (1059 mAh g −1 at 1675 mA g −1 ) and long lifespan of 200 cycles at 25 °C. These advances enlighten direction for future KSBs development.