A Core‐Shell NiFe 2 O 4 @SiO 2 Structure as a High‐Performance Anode Material for Lithium‐Ion Batteries

Smart surface coatings composed of transition‐metal oxides are shown to significantly improve the cycling performance of batteries. Currently, most studies are mainly focused on coating materials such as TiO 2 and carbon‐based materials. However, these coating materials face significant challenges, including their low capacity and tedious processing. Herein, a simple and novel amorphous SiO 2 coating is successfully used on the surface of NiFe 2 O 4 to form a core‐shell structure. When tested as an anode, it delivers a high initial discharge capacity of 2022.3 mAh g −1 and retains a high specific capacity of 1224.6 mAh g −1 after 100 cycles at a current density of 0.1 C. The superior performance of NiFe 2 O 4 @SiO 2 is mainly attributed to the SiO 2 coatings, which can provide a high capacity, alleviate drastic volume changes in NiFe 2 O 4 and form a stable solid electrolyte interphase (SEI) layer. The results demonstrated that SiO 2 can be used as a novel coating material to improve the cycling properties of metal oxide materials.