Red Phosphorus Nanoparticle@3D Interconnected Carbon Nanosheet Framework Composite for Potassium-Ion Battery Anodes.

Red phosphorus (P) has been recognized as a promising storage material for Li and Na. However, it has not been reported for K storage and the reaction mechanism remains unknown. Herein, a novel nanocomposite anode material is designed and synthesized by anchoring red P nanoparticles on a 3D carbon nanosheet framework for K-ion batteries (KIBs). The red P@CN composite demonstrates a superior electrochemical performance with a high reversible capacity of 655 mA h g-1 at 100 mA g-1 and a good rate capability remaining 323.7 mA h g-1 at 2000 mA g-1 , which outperform reported anode materials for KIBs. The transmission electron microscopy and theoretical calculation results suggest a one-electron reaction mechanism ofP + K+ + e- → KP, corresponding to a theoretical capacity of 843 mA h g-1 ,which is the highest value for anode materials investigated for KIBs. The study not only sheds light on the rational design of high performance red P anodes for KIBs but also offers a fundamental understanding of the potassium storage mechanism of red P.