A general strategy for enabling Fe₃O₄ with enhanced lithium storage performance: Synergy between yolk-shell nanostructures and doping-free carbon

Transition metal oxides such as Fe₃O₄ have been widely explored as the anode material for lithium-ion batteries (LIBs). The construction of yolk-shelled structure and doping-free carbon shell is considered as an ideal strategy to advance their lithium storage properties. Herein, a facile and scalable strategy is provided to fabricate the carbon shell on the surface of Fe₃O₄ nanocubes. Then, a series of yolk-shelled Fe₃O₄ nanocubes are synthesized through etching-in-a-box strategy. Thanks to the doping-free carbon shelled and the void between the Fe₃O₄ and carbon, the yolk-shelled Fe₃O₄ nanocubes electrode as anode materials for LIBs display a high specific capacity (910 mA h g⁻¹ at 100 mA g⁻¹) and excellent cycle stability (451 mA h g⁻¹ after 2000 cycles at 5 A g⁻¹). The method to produce doping-free carbon shell is easy and efficient and can be readily extended to design other high-performance LIBs anode materials.