Enhanced pseudocapacitive performances of eco-friendly co-precipitated Fe-doped cerium oxide nanoparticles

Abstract

In this study, we report a method to enhance the performance of environmentally friendly cerium oxide (CeO2) based pseudocapacitive electrode materials synthesized by a facile and safe co-precipitation method. Although co-precipitation can be considered as one of the most safe and facile procedures for the preparation of metal oxide nanoparticles, co-precipitated CeO2 often exhibits substantially reduced specific capacitance. However, by simply doping Fe into CeO2, we observed a notable enhancement in the performance of the CeO2 electrode. Although co-precipitated CeO2 demonstrates a specific capacitance of 121.0 F g-1 at 1 A g-1, the performance of the CeO2 electrode increased by 4.6 times to 559.0 F g-1 after 10 at.% Fe doping (10FDC). The specific capacitance of 10FDC at a high rate (10 A g-1) significantly increased by 8.9 times compared to that of CeO2 (21.6 F g-1 for CeO2 and 192.7 F g-1 for 10FDC). In addition, 10FDC exhibited excellent cycling stability, and less than 5% decrease in its specific capacitance was observed even after 7,300 charging and discharging cycles. The mechanism behind the capacitance enhancement was investigated via electrochemical analysis, which suggested that the contribution of the surface-capacitive limited process and the electrical conductivity of the electrode enhanced after Fe doping. Our study proposes a new possibility for the development of high-performance eco-friendly energy storage materials via the modification of electrical properties and introduction of defects by facile acceptor doping.