Electrochemical Deposition of Manganese Oxide on Paper-Based Laser-Induced Graphene for the Fabrication of Sustainable High-Energy-Density Supercapacitors

Laser-induced graphene (LIG) is widely used to fabricate microsupercapacitors (MSCs) on various sustainable substrates, such as wood, cork, and lignin. However, the fabrication of MSCs, especially high energy density devices on paper, has rarely been reported. In this work, LIG electrodes are fabricated on wax-coated paper, followed by electrochemical deposition of manganese oxide (MnO₂). The obtained LIG/MnO₂ supercapacitors exhibit a maximum areal capacitance of 86.9 mF cm⁻², while a device with pristine LIG electrodes exhibit a capacitance of 9.1 mF cm⁻², both measured at a current density of 0.1 mA cm⁻². In addition, the supercapacitor exhibits good cycling stability, retaining 80% of its initial capacitance after 1000 charge/discharge cycles at a current density of 1 mA cm⁻². Notably, the LIG/MnO₂ supercapacitor exhibits an exceptionally high energy density of 7.3 µWh cm⁻² at a power density of 38.8 µW cm⁻². In summary, a simple, fast, scalable, reproducible, and energy-efficient fabrication method is represented using electrochemical deposition of manganese oxide on paper-based laser-induced graphene, which are natural, abundant, and sustainable materials, paving the way for large-scale production of environmentally friendly supercapacitors.