Moderate oxygen-deficient Fe(III) oxide nanoplates for high performance symmetric supercapacitors

As a promising anode material for supercapacitors, Fe2O3 has been widely studied but still face the problem of low conductivity. Inducing oxygen vacancy (Vo) into Fe2O3 is a widely used approach to tune the conductivity to enhance its capacitive performance, but there is little research on the influence of Vo content. Herein, we report the effect of Vo in Fe2O3 nanoplates with various content. We tuned the Vo content by annealing at 200-500 degrees C. XPS and EPR were taken to characterize the Vo content, ranging from 11% to 26%. Electrochemical results show that FO-300 with 17% Vo has the highest capacity of 301 mAh g(-1), and the capacity of the highest Vo content's (26% Vo) is only 107 mAh g(-1). The symmetric supercapacitor based on FO-300 shows a considerably high energy density of 58.5 Wh kg(-1) at a power density of 9.32 kW kg(-1) and remains 84.6% after 12,000 cycles. (C) 2020 Elsevier Inc. All rights reserved.