Optimization studies on output stabilization time and graphene oxide concentration in graphene-based flexible micro-supercapacitor

Abstract

Miniature energy storage devices are vital for developing flexible and wearable electronics. This paper discusses the fabrication of flexible laser-induced graphene-based micro-supercapacitors (MSCs) using a layered polyimide film and graphene oxide as the precursor for laser scribing. The areal capacitance of the MSCs was assessed daily after applying a H₂SO₄/PVA gel electrolyte. The capacitance displayed a substantial increase in the early days before stabilizing at a consistent value. The stabilization time was evaluated through systematic experimentation conducted over ten consecutive days. The experiments showed that the capacitance stabilized after six days. Various concentrations of graphene oxide were used to assemble the MSCs, and their performance was evaluated to determine the optimal concentration. The electrochemical impedance spectroscopy revealed that the supercapacitor fabricated with the optimum concentration of graphene oxide exhibited the lowest resistance. The optimized MSC displayed an areal capacitance of 10.07 mF/cm2 at a current density of 13 µA/cm2. The device could maintain a reliable output at different bending states and retain 87.9% of its original capacitance after 5000 charge-discharge cycles, highlighting its suitability for flexible and self-powered systems.