Enhanced redox kinetics and capacitance in ceria doped cobalt metal organic framework derived mesoporous carbon electrodes for supercapacitors

In this study, a series of ceria-doped cobalt-based composites were synthesized via the incorporation of cobalt and cerium precursors into trimesic acid-based metal–organic frameworks (MOFs), followed by pyrolysis to obtain Co–CeO₂/C hybrid materials. The thermal decomposition of the MOF structure facilitated the in-situ formation of a conductive carbon matrix comprising carbon nanotubes (CNTs) and carbon nanospheres, catalyzed by cobalt nanoparticles. Among the prepared composites, the 5Co-5Ce/C sample exhibited the most promising electrochemical performance, delivering a high specific capacitance of 839F g⁻¹ at a current density of 0.1 A g⁻¹ and demonstrating excellent cycling stability, with 97% capacitance retention after 6000 charge- discharge cycles at 10 A g⁻¹. The superior performance is attributed to the synergistic effect between cobalt and cerium oxide, wherein CeO₂ not only enhances faradic charge storage through reversible redox reactions but also promotes the development of a mesoporous structure. Cerium was found to influence the crystallization behavior of cobalt during pyrolysis, thereby regulating the growth and distribution of CNTs and nanospheres. This structural refinement contributes to an increased electrochemically active surface area and improved ion transport kinetics, leading to enhanced overall capacitive behavior. These results highlight the potential of Co–CeO₂/C composites as promising electrode materials for high-performance supercapacitor applications.