In situ synthesis of mesoporous NiO nanoplates embedded in a flexible graphene matrix for supercapacitor electrodes

[Display omitted] •Mesoporous NiO/GNS composites were fabricated by in-situ thermal deposition.•Graphene matrix serves as an efficient conductive network for supercapacitor electrodes.•Graphene matrix offered accessible electroactive sites for electrochemical reactions.•The nanocomposites exhibited high performance as supercapacitor electrodes. Scholars have attached increasing attention to Graphene nanosheet (hereinafter referred to as GNS)-loaded transition metal oxide composites owing to the ability of attaching inorganic nanoparticles with better capacity and capacitance and better capacity than GNS of conductive polymer materials. A novel mesoporous structure of NiO nanoplates encapsulated in graphene matrix was synthesized and designed rationally. The composite composed of GNS and mesoporous NiO nanoplates can expand the approximate specific surface area of electrolyte. It has various advantages, such as good charge transport and short ion diffusion path. In addition, the interconnected graphene conducting network, as an adhesive, can maintain structural stability and promote charge transport by encapsulating mesoporous NiO nanoplates. The specific capacity is increased to 1050 F g−1 through the improved optimized NiO/GNS hybrid electrodes. This study provides a new idea for the design and manufacture of high performance transition metal oxide energy storage devices.