A molten salt route to binder-free CeO2 on carbon cloth for high performance supercapacitors

Abstract

Cerium oxide is one of the most abundant and environment-benignity rare earth oxides, which is thus of interesting to explore its feasibility to serve as a safe and efficient candidate for supercapacitor electrodes. We report herein a facile one-step molten salt method to synthesize CeO2 nanoparticles abundant in surface oxygen vacancies, which are directly grown on a carbon cloth (CeO2@CC). The CeO2@CC exhibits a high specific capacitance of 811.5 mF cm−2 at the current density of 5 mA cm−2 in −0.8–0 V, with a good capacitance retention of 86.3 % at 5 mA cm−2 after 10,000 cycles in 6 M KOH aqueous electrolyte. When assembled with a Co3O4@CC positive electrode, the Co3O4@CC//CeO2@CC asymmetric supercapacitor achieves an energy density of 0.11 mWh cm−2 at a power density of 3.25 mW cm−2. Both the abundant oxygen vacancies and the conductive carbon cloth contribute to the electrochemical performance. This work suggests that CeO2 could be a candidate material for high performance supercapacitors.