Na<sub>2</sub>FePO<sub>4</sub>F/Biocarbon Nanocomposite Hollow Microspheres Derived from Biological Cell Template as High‐Performance Cathode Material for Sodium‐Ion Batteries
Haiming Li, Tailin Wang, Xue Wang, Guangda Li, Jianxing Shen, Jinling Chai
Abstract
Abstract We have 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 the 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.