Zinc Oxide/Zinc Fluoride Nanocomposites With Groundnut Shell‐Derived Activated Carbon Electrodes for Energy Storage Applications

ABSTRACT In this work, zinc oxide (ZnO) and zinc oxide/zinc fluoride (ZnO/ZnF 2 ) nano composites were prepared by the hydrothermal method for asymmetric supercapacitor applications. ZnO/ZnF 2 composites represent a new class of electrode materials for supercapacitors with synergistic electrochemical properties. Incorporating fluorine into ZnO introduces additional charge carriers and decreases defect‐related recombination losses, enhancing its electrical conductivity. ZnF 2 in the composite contributes to structural stability and offers more redox‐active sites, allowing an enhancement in charge storage ability. The XRD confirms the formation of ZnO, ZnO/ZnF 2 , and ACGS and is supported by the micro‐Raman analysis. The oxidation states of zinc, oxygen, and fluorine in ZnO/ZnF 2 composites are confirmed by the XPS analysis. The ZnO nanoparticles had a coral‐like structure, while the ZnO/ZnF 2 had a needle‐like morphology. The surface areas of the by BET analysis are found to be 65.021,14.77, and 433.37 m 2 /g, respectively, for ZnO, ZnO/ZnF 2 , and activated carbon from groundnut shell (ACGS). From the three‐electrode analysis, the specific capacitances of ZnO, ZnO/ZnF 2 , and ACGS were found to be 138.70 F/g @ 2.5 A/g, 667.06 F/g @ 2.5 A/g, and 15.672 F/g @ 3 A/g, respectively. The two‐electrode system, ZnO‐ZnF 2 //ACGS device, has a specific capacitance of 184.3 F/g with capacitance retention of 92.84% over 4000 cycles @ 3 A/g current density.