MgO templated carbons: Effect of synthesis methodology on the morphology, surface chemistry and supercapacitor performances

Templating method is a widely adopted route to prepare porous carbon, while the effect of methodology on the structure and performances of the derived porous carbon was rarely focused. Herein, we employed a commercial MgO as template and catechol/formaldehyde as starting materials to prepare porous carbon by incipient impregnation method (the derived product denoted as MgC-I) and aqueous self-assembly method (the derived product denoted as MgC-S), respectively. Systematically analysis indicates that impregnation method favors the construction of two-dimensional structure, while, aqueous self-assembly method benefits formation of densified structure. Concerning to the surface chemistry, aqueous self-assembly method enables more residual oxygenic functionalities than that of impregnation derived ones. As electrode for supercapacitor in aqueous electrolyte, the MgC-S achieves superior volumetric performances including high specific volumetric capacitance of 319 F/cm3@1.0 A/g and large energy density of 27.9 Wh/L@1193 W/L, showing a potential for practical energy storage devices. Whereas, in organic electrolyte of 1.0 M TEANBF4/AN, the MgC-I electrode show a superior energy storage ability with energy density of 40.5 Wh kg−1@1350 W kg−1, the value is about six times higher than that of MgC-S based one. This study provides a reference for how to choose synthesis methods for preparing carbon materials with specific target.