Defect and Pore Channel Coordinated Regulation: Secondary Calcination Reconstructs the Electronic Structure and...

The application of supercapacitors is hindered by inefficient ion diffusion and interfacial charge transfer dynamics in electrode materials. We report a simple secondary calcination strategy for controlling thermal etching of graphite-phase carbon nitride (GCN-1 and GCN-2), and simultaneously optimizing the physical structure and electrochemical properties. The experimental results showed that a three-dimensional network with excess mesopores was successfully formed. The specific surface area of the fabricated sample was increased by 3.1-fold. The work function and zeta potential of GCN-2 decreased following secondary calcination, which exhibited outstanding capacitance. At current densities of 0.5-10 A/g, the capacitance retention of GCN-2 was 1.48-fold higher than that of GCN-1.The capacitance increased by 2.8-fold after secondary calcination owing to the synergistic effects of the multilevel pore structure and introduced defects.