Red phosphorus: A rising star of anode materials for advanced K-ion batteries

Recent advances in emerging red phosphorus anodes with high capacity and superior cost-effectiveness have opened up a new avenue to build next-generation high-performance K-ion batteries (KIBs). This mini-review focuses on the recent progress on development of red phosphorus anode materials for highly-efficient potassium ion storage. The review is started with a short introduction to expound why red phosphorus is a valuable and promising anode material for KIBs. After that, the synthetic methods of red phosphorus anode materials are briefly summarized, including ball-milling, evaporation-deposition, and others. Then, the electrochemical mechanism of red phosphorus anodes for potassium ion storage is summarized and discussed. Next, some useful improvement strategies are put forward to address the challenges facing red phosphorus anodes, encompassing carbon hybridization, nanostructure engineering, defect engineering, chalcogenide modification, construction of passivation layers, electrolyte optimization, and phosphide alloying. Finally, we present a brief summary and some perspectives for further development of red phosphorus materials.