Graphene modified LiFePO4 cathode materials for high power lithium ion batteries

Graphene-modified LiFePO4 composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO4 nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO4 primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO4 nanoparticles and graphene sheets was beneficial for Li+ diffusion. The composite cathode material could deliver a capacity of 70 mAh g(-1) at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.