Low‐Temperature Synthesis of Honeycomb CuP2@C in Molten ZnCl2 Salt for High‐Performance Lithium Ion Batteries

Abstract Phosphorus‐rich metal phosphides have very high lithium storage capacities, but they are difficult to prepare. A low‐temperature phosphorization method based on Mg reducing PCl 3 in ZnCl 2 molten salt at 300 °C is developed to synthesize phosphorus‐rich CuP 2 @C from a Cu‐MOF derived Cu@C composite. Abnormal oxidation of Cu by Zn 2+ in the molten salt is observed, which leads to the porous honeycomb nanostructure and homogeneously distributed ultrafine CuP 2 nanocrystals. The honeycomb CuP 2 @C exhibits excellent lithium storage performance with high reversible capacity (1146 mAh g −1 at 0.2 A g −1 ) and superior cycling stability (720 mAh g −1 after 600 cycles at 1.0 A g −1 ), showing the promising application of P‐rich metal phosphides in lithium ion batteries.