Cathode materials for potassium-ion batteries: current status and perspective

Potassium-ion batteries (PIBs) have recently attracted considerable attention in electrochemical energy storage applications due to abundant and widely distributed potassium resources and encouraging intercalation chemistries with graphite, the commercial anode of lithium-ion batteries. One main challenge in PIBs, however, is to develop suitable cathode materials to accommodate the large size of K+ ions with reasonable capacity, voltage, kinetics, cycle life, cost, etc. In this review, recent advancements of cathode materials for PIBs are reviewed, covering various fundamental aspects of PIBs, and various cathode materials in terms of synthesis, structure, and electrochemical performance, such as capacity, working potential, and K-storage mechanisms. Furthermore, strategies to improve the electrochemical performance of cathode materials through increasing crystallinity, using buffering and conducting matrixes, designing nanostructures, optimizing electrolytes, and selecting binders are summarized and discussed. Finally, challenges and prospects of these materials are provided to guide future development of cathode materials in PIBs.Qing Zhang, Zhijie Wang, Shilin Zhang, Tengfei Zhou, Jianfeng Mao, Zaiping Gu