Enhanced Electrochemical Performance of Highly Porous CeO2-Doped Zr Nanoparticles for Supercapacitor Applications.

The aim of this work was to develop an ultrasonic-assisted synthesis method for the fabrication of CeO2-doped Zr nanoparticles that would improve the performance of supercapacitor electrodes. This method, which eliminates the need for high-temperature calcination, involves embedding CeO2 into Zr nanoparticles through 1 hr (CeO2-Zr-1) and 2 hrs (CeO2-Zr-2) of ultrasonic irradiation, resulting in the formation of nanostructures with significant improvements in their electrochemical properties. Through physicochemical analysis, we observed that the CeO2-doped Zr nanoparticles, particularly those treated for 2 hrs (CeO2-Zr-2), exhibit superior crystalline phase purity, optimal chemical surface composition, minimal agglomeration with particle sizes below 50 nm, and an impressive average surface area of 178 m2/g. Compared to the 1 hr irradiation samples (CeO2-Zr-1) and undoped CeO2 nanoparticles, the (CeO2-Zr-2) electrodes demonstrated a remarkable capacitance of 198 Fg-1 at a current density of 1 A/g while maintaining ~94.9% of their capacity after 3750 cycles. This indicates not only good reversibility but also exceptional stability. In (CeO2-Zr-2) samples, the nanospherical structure achieved through ultrasonic synthesis is responsible for the enhanced capacitive behavior and stability, along with the synergistic effects caused by Zr doping, which improves the CeO2 nanoparticle conductivity to a significant extent. Surface areas of the electrodes are larger due to the combination of these two materials, which contribute to their superior performance.