Starch/methyl cellulose-based microsupercapacitors for on-chip applications

Micron thin films and microsupercapacitors based on polyvinyl alcohol, starch, methyl cellulose, and nickel acetate have been fabricated using the one-step formation of laser-induced graphene. Surface finishing of films and decomposition of nickel acetate to nickel oxide have been achieved with the help of CO2 laser. The optical studies of thin films and microsupercapacitors have been conducted, which are highly transparent in the UV–visible regime. There is no need of binders, current collectors, or separators in interdigitated microsupercapacitors. Starch-based microsupercapacitors (PSM) have superior electrochemical performance and stability than methyl cellulose (PMM) in the presence of 6-M KOH electrolyte. The maximum capacitance of PSM is 28.89 µF cm−2 in 6-M KOH at the scan rate of 1 mV s−1 from cyclic voltammetry. The specific energy density is 93.75 × 10−6 µWh cm−2 and the power density is 0.12 µW cm−2. The PMM has a specific capacitance of 2.5 nF cm−2 when compared to PSM of 0.52 µF cm−2 without electrolyte. The cycle life of PSM is 2500 cycles which shows its robustness. The performance of the microsupercapacitors is better than the other gate dielectric materials used in transistors and in the range for integration of energy storage devices in on-chip electronic and photonic devices.