Graphene oxide conformally wrapped FeOOH/graphite composite anodes for lithium-ion batteries†

Abstract

β-FeOOH is among the most prevalent anode materials used in lithium-ion batteries (LIBs) due to its high theoretical specific capacity. However, the practical use of such anodes is severely constrained by their limited electrical conductivity and mechanical damage resulting from volume changes during electrochemical cycling. Herein, to circumvent these issues, an environmentally benign synthesis of FeOOH nanorods on graphite sheets encapsulated in a graphene oxide (GO) layer was designed. Graphite mitigated the agglomeration of FeOOH nanorods and provided a conductive network. In addition, GO alleviated volume expansion and established a denser solid-electrolyte interface during the initial cycle, which prevents excessive consumption of Li-ions and maintains cycle life and capacity. The resultant GO@Gr-FeOOH anode demonstrated outstanding electrochemical properties, with an extended lifespan and superior Li-ion diffusion coefficient. Accordingly, the GO@Gr-FeOOH sample retained a capacity of 716 mAh g⁻¹ at 0.2 C after 50 cycles and 428.7 mAh g⁻¹ at 0.5 C after 150 cycles. Therefore, this study presents an effective and practical approach to address the constraints of FeOOH-based anode materials using hybridization with diverse carbon component strategies.