Binding Fe2O3 nanoparticles in polydopamine-reduced graphene as negative electrode materials for high-performance asymmetric supercapacitors

Abstract

Ternary composite with immobilization of Fe2O3 nanoparticles (NPs) onto porous polydopamine-reduced graphene oxide framework, abbreviated as Fe2O3@PDA-RGO, was fabricated via a simple, scalable and cost-efficient hydrothermal reaction. The as-prepared 3D Fe2O3@PDA-RGO nanocomposite provides a specific surface area of 119.9 m2 g-1 on account of the well-dispersed Fe2O3 NPs (~35 nm) onto the PDA-RGO sheets as spacer. When applied as a special faradic electrode material in negative potential region, Fe2O3@PDA-RGO can offer 169 mA h g-1 (609 F g−1) at 1 A g-1. The fabricated AC//Fe2O3@PDA-RGO asymmetric supercapacitor (ASC) delivers an energy density of 35.8 W h kg-1 (0.94 mW h cm-3) at 800 W kg-1 (21 mW cm-3) and an outstanding cyclic stability (75.7% capacity retention after 10,000 cycles). The good performance of Fe2O3@PDA-RGO in single-electrode and ASC manifests the potential the ternary composite in energy storage devices.