▎ 摘　　要

The LiFePO4-Graphene/LiNi0.8Co0.15Al0.05O2 composite for lithium ion batteries has been prepared by a two-step dry-mixing and ball-milling procedure to achieve high capacity and high security of LiNi0.8Co0.15Al0.05O2. The crystalline structure, morphology and electrochemical performance were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectronic spectroscopy (XPS) and electrochemical tests. With the addition of graphene, the LiFePO4 nanoparticles can cover the surface of LiNi0.8Co0.15Al0.05O2 tightly, further protecting LiNi0.8Co0.15Al0.05O2 from the side reaction with electrolyte, increasing the utilization of active materials and enhancing the cycling performance. The conductive networks consisted of LiNi0.8Co0.15Al0.05O2 LiFePO4 and graphene can facilitate electron infiltration and transport, thus improving the rate performance. The LiFePO4-Graphene/LiNi0.8Co0.15Al0.05O2 composite with 20% (w/w) LiFePO4 content exhibits a reversible capacitance up to 202.5 mAh . g(-1) at 0.1 C, good rate capability with