Improved Electrochemical Performance of NiO Nanoflakes Anchored Polymer Nanocomposites for Energy Storage Applications

The hybrid polymer nanocomposites (PNCs) exhibit excellent physical and chemical properties that cannot be achieved by the parent compounds. PNCs have fascinated important research interests due to their promising potential applications, such as environmental remediation, supercapacitor, sensor, catalysis, and safety and security systems. In this present work, hybrid composites based on PVA/PVP with various concentrations of NiO nanoflakes have been prepared by the solution casting method. The structural, dielectric, surface morphological, and electrochemical performances have been investigated. The crystalline nature of PNCs improves with increasing NiO concentration, and it is confirmed by powder XRD. The surface morphology of the PNCs has been revealed by the FESEM analysis. The performance of the dielectric nature of the material has been studied at various temperatures using an AC impedance analyzer. From the results, PVA/PVP/0.75 wt.% NiO has a high relative dielectric constant value of 411.85 and a higher relaxation time of 1.57 x 10-2 s. The asymmetric supercapacitor (ASC) device has been fabricated with polymer nanocomposite as the positive electrode and activated carbon as the negative electrode. The higher specific capacitance value of the asymmetric supercapacitor device is 46.28 F/g for PVA/PVP/0.75 wt.% NiO, with an areal capacitance of 277.70 mF/cm2. Moreover, a high energy density of 1.11 Wh/kg and a power density of 83.33 W/kg has been achieved. After 5000 cycles, the capacitance of the device retains about 96% of its initial value.