Facile fabrication of oxygen vacancy-rich α-Fe2O3 microspheres on carbon cloth as negative electrode for supercapacitors

Abstract

There are an increasing attention of the oxygen vacancy α-Fe2O3 because of its high electron donor density and pseudocapacitance contribution. At present, the reported methods of generating oxygen vacancies are to reduce iron oxides or hydroxides through various reductants, such as H2 and NaBH4 etc. However, these reactions are complex, and difficult to control. Herein, a facile and controllable impurity-free hydrothermal method to synthesize α-Fe2O3 electrode with abundant oxygen vacancies, and uniformly aligned on a carbon cloth is developed in this work. Besides, the influences of reaction temperature on the morphology of oxygen vacancy-rich α-Fe2O3 (α-Fe2O3-Vo) microspheres have been systematically investigated. The morphology could be tuned and controlled by adjusting the reaction temperature. At 160 °C, the introduction of oxygen vacancies into α-Fe2O3 electrode can effectively increase the amount of active sites to improve specific capacitance as well as pseudocapacitance contribution, so the α-Fe2O3-Vo microspheres electrode exhibits a superior specific capacitance of 862.12 mF cm−2 at a current density of 1 mA cm−2, and the contribution of pseudocapacitance reaches 75.45% at the sweep rate of 10 mV s−1. The one-step hydrothermal reported in this work proposes a simple and effective strategy for designing oxygen vacancy-rich electrodes, and boost the capacitance of the electrodes.