Controlled synthesis of core-shell Fe2O3@N-C with ultralong cycle life for lithium-ion batteries

Abstract Development of low-cost electrode materials with long cycle life and high volumetric capacity is important for large-scale applications of lithium-ion batteries (LIBs). Here, an electrode made from Fe2O3 encapsulated with N-doped carbon (Fe2O3@N-C) via ZIF-8 coating and carbonization process is reported. A cavity was generated between the Fe2O3 and N-C material during the carbonization process that is conducive to alleviating the volume expansion of Fe2O3. As a result, the Fe2O3@N-C composite exhibits a high specific capacity (1064 mAh/g at 0.1 A/g) and cycle stability (803.6 mAh/g at 1.0 A/g after 1100 cycles) when used as the LIB anode. In addition, the influence of carbonization under air on the LIB performance was investigated by controllably changing the crystal phase of Fe2O3 and the thickness of the carbon layer. This work provides a new method for the design and fabrication of yolk-shell composite electrodes for LIBs and other applications.