A novel litchi-like LiFePO4 sphere/reduced graphene oxide composite Li-ion battery cathode with high capacity, good rate-performance and low-temperature property

High capacity and good safety secondary batteries are desired for portable electronics and electric vehicles. Currently, an effective method for simultaneously improving the intrinsically poor conductivity and the low capacity of cathodes remains a challenge. Here we present a biomimetic composite consisting of novel litchi-like LiFePO4 spheres assembled by 20 nm nanoparticles and reduced graphene oxides (rGO). In particular, this biomimetic cathode provides short electron transfer pathways inside the LiFePO4 spheres (through the hierarchical structure) and on the surface (by the interconnected rGO scaffold). The composite shows a high capacity of 161 mAh g(-1) after 200 cycles, accompanying with a good Coulombic efficiency of about 100%. In addition, the composite retains a capacity of 93 mAh g(-1) after cycling for 400 times, and shows a good capacity retention when cycling at -5 degrees C.