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

In this work we produced high-energy-density supercapacitors using paper-based laser-induced graphene (LIG) electrodes with electrodeposited manganese oxide (MnO2) and using as a substrate paper. First, LIG electrodes were fabricated on wax-coated paper utilizing a commercial CO2 laser cutter machine. Subsequently, MnO2 was electrodeposited onto the as-prepared LIG electrodes within a standard three-electrode cell setup. It was found that LIG fabricated with two laser scans yielded high-quality graphene, exhibiting sheet resistances as low as 21.9 ± 1.9 Ω sq-1. The LIG/MnO2 supercapacitor displayed a maximum areal capacitance of 86.9 mF cm-2, whereas a device utilizing pristine LIG electrodes exhibited a capacitance of 9.1 mF cm-2, both measured at a current density of 0.1 mA.cm-2. Additionally, the supercapacitor also displayed good cycle 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 demonstrated an exceptionally high energy density of 7.3 μWh cm-2, at a power density of 38.8 μW cm-2. In summary, we present an easy, fast, scalable, and energy-efficient fabrication method utilizing 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 supercapacitor.