Synthesis of GN/ MnO2 nanocomposite materials for photo-assisted supercapacitor with enhanced capacities

Supercapacitors with the advantages of high power density and rapid discharging rate have widespread applications in energy storage. Nevertheless, their development is hindered by the limitation of low specific capacity. Traditional approaches to enhance specific capacity primarily involve incorporating foreign atoms and blending with additional reactive substances. Herein, a photo-assisted supercapacitor electrode material (GN/MnO₂ nanocomposite) with excellent capacity is developed. As a photoactive material, graphene generates electrons and holes with photoirradiation. As the photogenerated carriers increase, electrons are separated from the holes and stored as charges. Photoirradiation is the driving force that promotes the energy storage and conversion of supercapacitors. Although there are many reports on GN/MnO₂ composites, there are still few reports on the photo-assisted energy storage of this composite material. The specific capacity of this photo-assisted GN/MnO₂ electrode materials could reach 210 F/g with photoirradiation. It was higher than that without photoirradiation (170 F/g). The development of this study provides important theoretical guidance and practical significance for the research of photo-assisted energy storage materials, and plays a significant role in advancing the progress of energy storage devices with high specific capacity.