Li₂FeSiO₄/C hollow nanospheres as cathode materials for lithium-ion batteries

Undoubtedly, it is imperative to figure out two stubborn issues concerning low electronic conductivity and sluggish lithium ion diffusion to promote the practical application of Li₂FeSiO₄ materials in lithium-ion battery (LIB) cathode. Herein, we report an innovative and simple strategy that combines a hydrothermal process with subsequent annealing to synthesize highly uniform Li₂FeSiO₄/C hollow nanospheres. During the hydrothermal process, polystyrene nanospheres are employed not only as the template but also, more tactfully, as carbon source to form amorphous carbon layers, which will function to enhance the electronic conductivity and restrict particle aggregations. The use of the LIB Li₂FeSiO₄/C hollow nanospheres as a LIB cathode delivers a desired stable capacity at each rate stage, and even at a high rate of 10 C, the hollow nanosphere cathode can present a specific discharge capacity as high as 50.5 mAh·g^-1. After 100 cycles, the capacity retentions at 1 and 10 C remain as high as 93% and 72%, respectively. The superior electrochemical performance is believed to be related to special architectures of the Li₂FeSiO₄/C hollow nanosphere cathode.