Ceria nanoflowers decorated Co3O4 nanosheets electrodes for highly efficient electrochemical supercapacitors

Abstract

Overcoming a low energy density (1–50 Whkg−1) limitation is a challenge for supercapacitor electrode materials. To achieve higher performance (up to 100 Whkg−1), the transition metal-based pseudocapacitors (PCs) have been utilized owing to advantages viz. Faradaic reversible redox reaction significantly boosts the capacitance compared to that of the traditional electrical double layers capacitors (EDLCs). In this work, ceria nanoflowers decorated Co3O4 nanosheets structured active material deposited on nickel foam (denoted as CeO2@Co3O4/NF) by hydrothermal synthesis, demonstrates enhanced supercapacitor performance due to high conductivity, large surface area, and stable reversible oxidation states of Ce3+/Ce4+ and Co2+/Co3+ and greatly supported the Faradaic redox reaction of PCs. The CeO2@Co3O4/NF electrode showed a high areal-specific capacitance of 1598 mFcm−2 at 1 mAcm−2 for the 0–0.5 V potential windows and stability up to 96.6% after 6000 cycles. In an asymmetric supercapacitor (ASC) device, the CeO2@Co3O4/NF was used as a positive electrode which revealed an excellent energy density and power density viz. 92 Whkg−1 and 1580 Wkg−1, respectively. Overall, the present research findings signify the advantages of the novel combination of nanostructured ceria and cobalt oxide active materials for enhanced supercapacitor performance.