FeC2O4@Fe2O3/rGO composites with a novel interfacial characteristic and enhanced ultrastable lithium storage performance

Iron oxalate (FeC2O4) is considered as a potential new energy storage material because of its high reversible capacity and attractive cost performance platform. However, the slow chemical reaction kinetics and unstable structures of FeC2O4 make it difficult to achieve high-rate and long-cycling lithium storage performance. Herein, a facile and scalable approach is developed to synthesize multilayer FeC2O4 coated with Fe2O3 nanodots and adsorbed on flexible conductive rGO matrix (FeC2O4@Fe2O3/rGO), which exhibits great potential as an anode material for high-rate and stable-cycling performance. Furthermore, encapsulation of Fe2O3 nanodots on surface of FeC2O4 particle promotes the formation of a stable core-shell structure with an irreversible organic layer as the shell, and inhibits the disintegration of repeated volume expansion of FeC2O4 particles at high current density. The improvement of cycling performance is attributed to the existence of flexible rGO which can work like a spider web and anchor of the FeC2O4@Fe2O3 composites onto its one-dimensional scaffold, providing an enhanced electrical pathway of high conductivity for the electrochemical reaction between Li and Fe. This work offers a promising material architecture for obtaining the stable and reliable anode materials with high energy density.