Nanocellulose-Assisted Growth of Manganese Dioxide on Thin Graphite Papers for High-Performance Supercapacitor Electrodes

High volumetric energy density, based on the entire electrodes, is necessary for the miniaturization of supercapacitors. The growth of manganese dioxide (MnO2) on graphite papers via chemical reactions was very limited, resulting in the inferior volumetric-specific capacitance. Cellulose nanofibers, coated on graphite papers, impressively enhanced the thickness of grown MnO2 layers and, thus, volumetric-specific capacitance. The symmetric supercapacitors displayed an extremely high volumetric energy density of 10.6 mWh/cm(3) at a power density of 0.11 W/cm(3). The performance was superior to that of MnO2-based symmetric and even asymmetric devices in the past studies. This research opens a new opportunity to fabricate high-performance supercapacitor electrodes by utilizing cellulose nanofibers detached from natural cellulose.