Microstructure and Superior Electrochemical Activity of Cu₃P/Reduced Graphene Oxide Composite for an Anode in Lithium-Ion Batteries

Abstract

Transition-metal phosphides/graphene composites are a promising new anode material for use in Li-ion batteries because of their high capacity for Li-ion storage. In this research, the copper phosphide (Cu3P)/reduced graphene oxide (RGO) composite is prepared successfully via a facile solvothermal method. A large quantity of Cu3P nanoparticles deposit uniformly and firmly on the surface of RGO nanosheets, which not only avoid the aggregation of Cu3P nanoparticles, but also prevent the re-stacking of graphene thereby retaining their extensive active surface area. As a result, the introduction of RGO nanosheets into Cu3P nanoparticles and their unique interfacial interaction give Cu3P/RGO composites outstanding electrochemical performance, such as good cycling stability, high initial discharge and reversible capacities. The material displays a high initial discharge and reversible capacity of 1578 mAh g−1 and 954 mAh g−1, respectively, at a current density of 500 mA g−1 and after 80 cycles. Even at the current density of 800 mA g−1, the reversible capacity is still 792 mAh g−1 after 80 cycles.