Synthesis and electrochemical performance of hierarchical nanocomposite of carbon coated LiCoPO4 crosslinked by graphene

We report the design and synthesis of a novel hierarchical LiCoPO4@C/G cathode material, consisting of carbon coated LiCoPO4 nanoparticles crosslinked by wrinkled graphene, for high-energy-density lithium ion batteries. This material is facilely prepared by a solid-state milling process followed by heat annealing. Its morphology and structure are characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction. It is revealed that the LiCoPO4 nanoparticles are coated by an amorphous carbon layer with ∼3 nm thickness and further crosslinked by wrinkled graphene. The LiCoPO4@C/G material delivers a high discharge capacity of 146.1 mAh g−1 at 0.1 C rate and 93.0 mAh g−1 at 2 C rate. The enhanced electrochemical properties are attributed to the nanosized LiCoPO4 particles and the high electronic conductivity resulted from the synergistic carbon coating and graphene crosslinking. Our work provides a facile approach to prepare high performance LiCoPO4 cathode materials for lithium ion batteries.