Controlled synthesis of mesoporous carbon nanosheets and their enhanced supercapacitive performance

Mesoporous carbon nanosheets (MCNs) were synthesized using porous magnesium oxide (MgO) layer as the template precursor and resol as the carbon source. The morphology of the mesoporous carbon particles can be easily controlled by altering the mass ratio of MgO to resol. The structural characterization demonstrates that the interlaced MCNs can be formed when MgO/resol is 1:1 and they possess the carbon nanolayer with a thickness of about 5 nm and a width of about 200 nm. The quantities of mesopores and micropores endow the MCNs with a large surface area of 1,180 m²?g^?1 and a high pore volume of 1.56 cm³?g^?1. The supercapacitive performance of carbon products synthesized with various MgO/resol ratios was evaluated using cyclic voltammetry and galvanostatic charge–discharge techniques. The results show that the interlaced MCNs exhibit the highest specific capacitance of 241 F?g^?1, the best rate capability and cycling stability, which are attributed to the fast electrolyte ion transport or diffusion throughout the electrode matrix and effective utilization of the electrical double-layer capacitance of carbon layer.