Analyzing the charge contributions of metal–organic framework derived nanosized cobalt nitride/carbon composites in asymmetrical supercapacitors

Abstract

Metal–organic framework derived nanostructures have recently received research attention owing to their inherent porosity, stability, and structural tailorability. This work involves the conversion of zeolitic imidazolate frameworks (ZIFs) into cobalt nitride nanoparticles embedded within a porous carbon matrix (Co₄N/C). The as-prepared composite shows great synergy by providing a high surface area and efficient charge transfer, showcasing outstanding electrochemical performance by providing a specific capacitance of 313 F g⁻¹. Moreover, we meticulously conducted calculations to derive the most precise values for the surface contribution, a crucial aspect often overlooked in existing literature, thereby ensuring the reliability of our calculated measurements. Correct calculations of surface and diffusion charge contributions are necessary for evaluating the overall electrochemical performance of supercapacitors. For practical utility, we successfully assembled an asymmetrical supercapacitor employing the Co₄N/carbon composite as the negative electrode that achieved an impressive energy density of 26.6 W h kg⁻¹ at a power density of 0.36 kW kg⁻¹. This study opens up new avenues for investigating the use of other metal nitride nanoparticles embedded in carbon structures for various energy storage applications.