High-rate performance of a three-dimensional LiFePO4/graphene composite as cathode material for Li-ion batteries

Based on the graphene sheet stacking via van der Waals and π-π interactions during the solvothermal treatment, a 3D structure, with the carbon-decorated LiFePO₄ particles embedded in interconnected graphene aerogels, is established. As the graphene and the carbon-decorated LiFePO₄ particles contact adequately and efficiently, the rate performance of the LiFePO₄-based cathode material is enhanced significantly. Thus, the 3D carbon-decorated LiFePO₄/graphene composite cathode shows high reversible capacities of 112.4 and 96.7 mAh g^-1 at extremely high rates of 30C and 50C, respectively. Moreover, good high-rate cycling stability is achieved with a capacity retention of 96.3% after 300 cycles at 30C. The excellent high-rate performance can be ascribed to the 3D conductive framework constructed by graphene, which facilitates fast electron and lithium ion transport. These results not only demonstrate the superiority of the 3D graphene framework in electrode material design, but also offer a promising candidate for high-rate cathode material in high-power Li-ion batteries.