Cathode materials for high-performance potassium-ion batteries

Potassium (K)-ion batteries (PIBs) have been considered promising as candidates for large-scale energy storage systems due to their potentially low cost and high abundance of K. However, the K+ with a relatively large ionic radius generally makes the cathode materials show slow K+ diffusion kinetics and a large volume change during the charge/discharge process, resulting in unsatisfactory electrochemical performance. Therefore, the development of cathode materials with fast reaction kinetics and superior structural stability is very meaningful for achieving the practical applications of PIBs. Here, the recent progress on cathode materials for high-performance PIBs is overviewed. In addition, the effective strategies toward improving the electrochemical performance of cathode materials have been summarized, including hybridization with high conductive materials, morphology design, element substitution, electrolyte optimization, and surface modification. This review provides a whole picture and valuable guidance for developing suitable cathode materials for high-performance PIBs.