Superior lithium storage performance of an Fe3O4 anode encapsulated by dual-layered interwoven carbon nanostructures using a facile one-step pyrolysis approach

Abstract

Magnetite (Fe₃O₄) has garnered significant attention as a promising anode material for next-generation lithium-ion batteries (LIBs) due to its cost-effectiveness, high theoretical capacity, and environmental sustainability. However, its practical application is severely limited by poor electrical conductivity and significant volumetric expansion during charge–discharge cycles. To address these challenges, a composite of interwoven hard–soft carbon-coated Fe₃O₄ (HCSC@Fe₃O₄) has been prepared via a simple one-step pyrolysis approach. Microscopic structural characterization revealed that the carbon shell of the HCSC@Fe₃O₄ composite exhibited a unique dual-layer structure consisting of an outer carbon framework formed by in-plane porous S/N-codoping carbon sheets and an inner graphite-like carbon layer doped with N. Owing to this distinctive structure, the HCSC@Fe₃O₄-1000-1 anode exhibited exceptional electrochemical performance, delivering a high specific capacity of 1647 mA h g⁻¹ after 170 cycles at 100 mA g⁻¹ and 1009.6 mA h g⁻¹ after 520 cycles at 1000 mA g⁻¹. The outstanding rate capability, evidenced by discharge capacities of 1639 mA h g⁻¹ at 100 mA g⁻¹ and 849 mA h g⁻¹ at 1000 mA g⁻¹, is ascribed to the synergistic interaction between its unique dual-layered carbon structure, comprising hard and soft interwoven carbon. This eco-friendly and efficient strategy can be utilized in other anodes based on transition metal oxides, contributing broad potential for future LIB applications.