Flexible electronic devices find wide application in wearable electronics and foldable gadgets. This article reports chemical vapor deposited (CVD) few-layers graphene for a solid-state flexible supercapacitor device. Raman spectroscopy analysis reveals up to five layers in the graphene samples. Polyvinyl alcohol-Na2SO4 hydrogel membrane is used as a gel polymer electrolyte (GPE). 50 nm thick silver (Ag) deposited on polyethylene tere­phthalate (PET) through E-beam deposition served as the flexible current collector for the device. Galvanostatic charge-discharge (GCD) executed on the fabricated device to ana­lyze its electrochemical performance yielded a specific areal capacitance of 15.3 mF cm-2 at 0.05 mA cm-2 current density. The obtained power density of the fabricated device is 0.53 µWh cm-2 at a power density of 25 µW cm-2.

In the current study, we report a straightforward and affordable sol‐gel preparation approach for the fabrication of spinel CuCo2O4 nanorods for sodium ion‐based hybrid supercapacitor. The morphological and structural analysis shows that appropriate purity nanorods of CuCo2O4 are formed with good stoichiometry. The electrochemical study of CuCo2O4 nanorods reveals that the electrode has highest specific capacitance of 367 F g−1 at 1 A g−1 in 1 M Na2SO4 electrolyte. Evaluation of the diffusion kinetics of sodium ions through detailed electrochemical evaluations of cyclic voltammogram (CV) showing the charge storage kinetics of CuCo2O4 is primarily performed through the diffusive limited mechanisms, suggesting the battery‐like behavior of CuCo2O4 electrode. Hybrid supercapacitor (HSC) device is fabricated by utilizing CuCo2O4 for positive and reduced graphene oxide (rGO) for negative electrodes material. The polymer gel electrolyte is used in the form of hydrogel membrane made of PVA and Na2SO4, and the HSC device (rGO || CuCo2O4) exhibits energy density of 9.18 Wh kg−1. Therefore, sodium‐ion hybrid supercapacitor electrode materials for this investigation are established using a comprehensive electrochemical kinetics.