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

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 PCl₃ in ZnCl₂ molten salt at 300 °C is developed to synthesize phosphorus-rich CuP₂ @C from a Cu-MOF derived Cu@C composite. Abnormal oxidation of Cu by Zn²⁺ in the molten salt is observed, which leads to the porous honeycomb nanostructure and homogeneously distributed ultrafine CuP₂ nanocrystals. The honeycomb CuP₂ @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.