Ultrasmall Fe2O3 Nanoparticles Anchored on Three-Dimensional Hierarchical Porous Graphene-like Networks for High Rate Capability Supercapacitors

Abstract

An ultrasmall Fe<inf>2</inf>O<inf>3</inf> nanoparticle/three-dimensional hierarchical porous graphene-like (Fe<inf>2</inf>O<inf>3</inf>/3D HPG) composite has been synthesized by a facile hydrothermal method, which is investigated as a high performance electrode material for supercapacitors. In the composite, the ultra-small-sized Fe<inf>2</inf>O<inf>3</inf> nanoparticles, with an average size of approximately 5 nm, are uniformly distributed on the 3D HPG substrate. The as-prepared Fe<inf>2</inf>O<inf>3</inf>/3D HPG composite electrode exhibits good electrochemical performance with a maximum specific capacitance of 967 F g⁻¹ at 1.0 A g⁻¹ in the three-electrode system in 2.0 mol L⁻¹ KOH aqueous solution, and an outstanding rate capability (74 % capacitance retention at 30 A g⁻¹). In addition, the composite electrode also exhibits an excellent cycling performance with 92 % capacitance retention of the initial capacity after 5000 cycles at 1.0 A g⁻¹.