Achieving super lithium storage of FeC2O4/Gs composites with dual-level structured graphene sheets through electrostatic adherence

Abstract

Iron oxalate (FeC₂O₄) is a promising candidate as an anode material for lithium-ion batteries (LIBs) with its advantages of low cost and high capacity. However, its commercial application is limited by its poor electrical conductivity, which leads to slow chemical reaction kinetics. Herein, a novel FeC₂O₄-based composite (FeC₂O₄/Gs) with dual-level structured graphene sheets (Gs) was constructed via electrostatic adherence technology, which enhanced the combination form and composite effect for two discrepant materials. Based on the dual-level structured Gs in FeC₂O₄/Gs composites, micro-based Gs (∼5 μm) was dispersed between the FeC₂O₄ particles. Meanwhile, the nano-based (∼50 nm) Gs was coated and embedded on the surface of rod-like FeC₂O₄ particles. Because of the special structure of FeC₂O₄/Gs, it has a dual promotion of electron transport both within and on the surface of the FeC₂O₄ particles, favoring electrochemical activity and efficiently inducing the conversion reaction. Consequently, the FeC₂O₄/Gs composite achieved a high reversible capacity of 820 mA h g⁻¹ and excellent cycling stability with a capacity retention of 41% after 200 cycles under 10C. This study provides a novel opportunity to design composites and electrodes with electronic conductivity, excellent electrochemical activity and ultrahigh cycling stability for lithium storage.