Simple fabrication of laser-induced graphene functionalized with a copper-based metal–organic framework and its application in solid-state supercapacitors

Abstract

Flexible thin-film electronics based on functionalized laser-induced graphene (LIG) hold great promise for a diverse range of applications, including biosensors and energy storage devices. In this study, we present a simple and direct method for synthesizing LIG functionalized with a copper-based metal–organic framework (MOF). The proposed synthesis procedure involves a one-step laser photothermal process on the surface of a carbon-rich polyimide to obtain LIG, followed by a simple layer-by-layer technique for growing Cu-BTC crystals within the porous structure of LIG. Structural characterization through various techniques confirms the successful deposition of crystalline Cu-BTC within the electrically conductive LIG surface. Cu-BTC@LIG composites are highly valuable candidate materials for multiple applications. In particular, we demonstrate the use of Cu-BTC@LIG as an electrode for electrochemical supercapacitors, increasing the specific capacitance by up to six times compared to LIG-only electrodes (reaching values of 2.8 mF cm⁻² at 54.3 μA cm⁻² or 2.1 mF cm⁻² at 10 mV s⁻¹) due to the double layer capacitance and pseudocapacitance contribution of Cu-BTC. The Cu-BTC@LIG electrodes also exhibit superior energy density (7.4 times higher at a power density of 21.26 μW cm⁻²) and stability over multiple charge–discharge cycles (>5000), making it a promising material not only for energy-storage devices but also for numerous applications in flexible electronics.