Chemical vapor deposited graphene-based quasi-solid-state ultrathin and flexible sodium-ion supercapacitor

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.