Zinc doping effect on the structural and electrochemical properties of LaCoO3 perovskite as a material for hybrid supercapacitor electrodes

Abstract

In the present study, a series of LaCo1−xZnxO3 (0 ≤ x ≤ 0.1) perovskite-type oxides was successfully synthesized via the sol-gel process followed by thermal treatment. The zinc doping effect on the structure, the surface chemical composition, morphology, porosity, as well as the electrochemical properties of LaCoO3 has been investigated, for the first time, for potential use as a material for supercapacitor electrodes. We infer from the results that the LaCo0.95Zn0.05O3 electrode provides the best specific capacitance (300.47 F/g); this is almost four times higher compared to the undoped electrode (75.36 F/g). The electrode material also shows an excellent capacitance retention of 85.73% after 5000 cycles at 5 A/g. In addition, a hybrid supercapacitor with high energy density was constructed by combining LaCo0.95Zn0.05O3 with activated carbon. The LaCo0.95Zn0.05O3//activated carbon hybrid device offers a high energy density of 36.12 Wh.kg−1 at a power density of 390.35 W.kg−1. The device is characterized by an outstanding retention of capacitance of 81% after being subjected to 5000 successive charge-discharge cycles.