Na2FePO4F/biocarbon nanocomposite hollow microspheres derived from biological cell template as high-performance cathode material for sodium-ion batteries.

we successfully synthesized Na 2 FePO 4 F/biocarbon nanocomposite hollow microspheres from Fe III precursor as cathodes for sodium-ion batteries through self-assembly of yeast cell biotemplate and sol-gel technology. The carbon coating on nanoparticle surface with a mesoporous structure enhances electron diffusion into Na 2 FePO 4 F crystal particles. The improved electrochemical performance of Na 2 FePO 4 F/biocarbon nanocomposites is attributed to the larger electrode-electrolyte contact area and more active sites for Na + on the surface of hollow microspheres compared with those of Na 2 FePO 4 F/C. The Na 2 FePO 4 F/biocarbon nanocomposite exhibits a high initial discharge capacity of 114.3 mAh g -1 at 0.1 C, long-cycle stability with a capacity retention of 74.3% after 500 cycles at 5 C, and excellent rate capability (70.2 mAh g -1 at 5 C) compared with Na 2 FePO 4 F/C. This novel nanocomposite hollow microsphere structure is suitable for improving the property of other cathode materials for high-power batteries.