B, N-codoped carbon skeletons with multistage pore structure for supercapacitor and capacitive deionization

Abstract

Due to the advantages of simple structure regulation, low cost and easy availability, asphalt-based carbon material has become a promising electrode material in supercapacitive research field. In this work, a boron-nitrogen co-doped multistage porous carbon material (BNMPC) was successfully prepared by various ways to regulate the nano-structure of asphalt-derived carbon material. From the synergistic activation of ammonium borate and potassium bicarbonate, the advanced pore structures were constructed, effectively ensuring full utilization of high specific surface area. At the same time, B and N atoms were successfully doped into the carbon lattice, which significantly improved the material's wettability and pseudocapacitance contribution. Ammonium borate (as doping and activation dual functional agent) secure the doping uniformity and stability of material properties. In addition, the B-N valence bond from B and N doping can improve the material's conductivity and ion transport kinetics, providing a strong guarantee for good supercapacitive properties. In supercapacitors (SC), BNMPC//BNMPC devices demonstrate superior performance, affording energy densities and power densities up to 8.3 Wh kg⁻¹ and 2.5 kW kg⁻¹, respectively. As for capacitor deionization (CDI) device, its salt adsorption capacity can reach 14.8 mg g⁻¹. In summary, the carbon materials prepared in this study show desirable capacitive properties.