Tailoring the supercapacitive behaviors of Co/Zn-ZIF derived nanoporous carbon via incorporating transition metal species: A hybrid experimental-computational exploration

Abstract The elaborate design of electrode materials plays a critical role in developing high-performance supercapacitors. In the present work, a convenient avenue is adopted to adjust the supercapacitive behavior of carbon-based electrodes by incorporating transition metals (Co, Nb, Mo, and Fe) into Co/Zn-ZIF derived nitrogen-doped porous carbon (NDPC). The experiment results demonstrated that incorporating transition metal species tuned the microstructure, nanoporous textures, and hydrophilicities of as-prepared Co-NDPC and M/Co-NDPC (M = Nb, Mo, or Fe), which further tailored their supercapacitive performance. Owing to the higher surface area, abundant pores, and superior wettability of Nb/Co-NDPC sample, the corresponding electrode showed the highest specific capacitance of 293 F g−1 at 0.5 A g−1 with an outstanding capacitance retention of 82% at 20 A g−1. All the electrodes displayed remarkable stability over 15,000 charge–discharge cycles. The first-principle density functional theory (DFT) calculations revealed that the superior capacitive behaviors of Nb/Co-NDPC electrode could be attributed to the uneven electrostatic potential surface and robust K+ ion adsorption ability. This work provides an elaborate strategy for designing novel and high-performance electrode materials by adopting DFT calculations for supercapacitors.