Multiple Electron Transfers Enable High‐Capacity Cathode Through Stable Anionic Redox

作者：Lichen Wu, Zhongqin Dai, Hongwei Fu, Mengkang Shen, Limei Cha, Yue Lin, Fanfei Sun, Apparao M. Rao, Jiang Zhou, Shuangchun Wen, Bingan Lu · 发表于：Advanced Materials · 年份：2025 · DOI：10.1002/adma.202416298 · 被引用次数：24 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced battery technologies research

Abstract Single‐electron transfer, low alkali metal contents, and large‐molecular masses limit the capacity of cathodes. This study uses a cost‐effective and light‐molecular‐mass orthosilicate material, K 2 FeSiO 4 , with a high initial potassium content, as a cathode for potassium‐ion batteries to enable the transfer of more than one electron. Despite the limited valence change of Fe ions during cycling, K 2 FeSiO 4 can undergo multiple electron transfers via successive oxygen anionic redox reactions to generate a high reversible capacity. Although the formation of O‒O dimers in K 2 FeSiO 4 occur upon removing large amounts of potassium, the strong binding effect of Si on O mitigates irreversible oxygen release and voltage degradation during cycling. K 2 FeSiO 4 achieves 236 mAh g −1 at 50 mA g −1 , with an energy density of 520 Wh kg −1 , which can be comparable with commercial LiFePO 4 materials. Moreover, it also exhibits 1400 stable cycles under high‐current conditions. These findings enhance the potential commercialization prospects for potassium‐ion batteries.