Phosphorus-Rich CuP Embedded in Carbon Matrix as a High-Performance Anode for Lithium-Ion Batteries.

Phosphorus-rich CuP and its carbon composites have been investigated as an anode material for lithium-ion batteries. Through a facile, low-cost mechanochemical reaction, microsized composites composed of active CuP particles uniformly embedded in the carbon matrix have been successfully synthesized. Combined structural and electrochemical characterizations show that phosphorus-rich CuP undergoes irreversible reaction with lithium, giving metal-rich CuP and amorphous phosphorus at the end of the first cycle. Both CuP and phosphorus are reversibly formed in subsequent cycles, contributing to a high reversible capacity of >1000 mA h g. By controlling the carbon content, the electrochemical reversibility and stability of CuP are greatly improved. The carbon composite demonstrates a remarkable lithium-storage capability in terms of a stable capacity of >720 mA h g over 100 cycles at 200 mA g, a high initial Coulombic efficiency of ∼83%, and a good rate capability with a capacity of >637 mA h g at 1.6 A g. The performance improvement is mainly associated with the formation of the conductive carbon network that offers high conductivity and fast reaction kinetics, as well as enhanced structural stability of CuP anode.