Fabrication of hafnium oxide/polypyrrole composite with enhanced electrochemical performance for supercapacitor electrode materials

Hafnium oxide has demonstrated significant potential in the semiconductor industry, yet its application in energy storage remains underexplored. This study introduces a cost-effective and straightforward in situ chemical oxidative polymerization method to synthesize polypyrrole (PPy)-supported HfO2nanoparticles, showcasing improved structural, optical, and electrochemical properties for supercapacitor applications. When assessed as electrode materials, the (HfO2)0.7(PPy)0.3composite demonstrated superior electrochemical performance, with a superb specific capacitance of 804 F/g at 5 mV/s and 2 A/g, outstanding energy density of 31 Wh/kg at a remarkable power density of 1800 W/kg and compared to its component counterparts in an aqueous alkaline electrolyte (1M KOH). Moreover, the nanocomposite exhibits enhanced electrochemical kinetics and 83% capacity retention after 5000 charge–discharge cycles at 10 A/g. The exceptional electrochemical results indicate that HfO2/PPy nanocomposites represent a powerful approach for next-generation energy storage electrodes.Graphical abstract