Robust freestanding laser-induced graphene electrodes for wearable energy devices

Abstract

Laser-induced graphene (LIG) offers a low-cost, eco-friendly method for graphene synthesis under ambient conditions, addressing limitations of conventional high-temperature, high-pressure processes. However, conventional LIG suffers from very poor mechanical robustness and adhesion, which limits the actual device applications especially wearable electronics. This is because single-sided laser irradiation often requires excessive laser power to achieve graphene formation throughout the entire thickness of the substrate, which leads to ablation, substrate loss, and collapse of the porous network—ultimately degrading electrochemical performance. To overcome these limitations, we introduce a double-sided laser irradiation process that sequentially irradiates both sides of a PEDOT:PSS/Kevlar nanofiber composite film to fabricate a freestanding LIG. This method minimizes ablation and maximizes active surface area of graphene electrode and enhance the areal capacitance and capacitance retention of flexible supercapacitors. Importantly, resulting LIG electrodes inherit the electrical conductivity of PEDOT:PSS and mechanical robustness of Kevlar nanofibers from the composite film, even after laser processing. These freestanding, transferable electrodes conformally adhere to substrates of various materials, curvatures, or flexibilities without additional support and serve as heaters, sensors, and reconfigurable energy modules. This work offers a scalable strategy for soft, multifunctional electronics, advancing wearable energy storage systems, conformable sensors, and integrated flexible devices.