Carbon-encapsulated MnO composites derived from Mn-hexamine coordination frameworks as high-performance supercapacitor electrodes

Investigating renewable, eco-friendly, carbon-based materials with superior electrochemical performance is pivotal for advancing the practical implementation of supercapacitors, yet it presents challenges. In this study, a novel MnO@C-HMT-T composite, consisting of porous carbon-encapsulated MnO, was synthesized from a Mn-hexamine coordinated precursor via an in-situ pyrolysis approach. Among the different materials prepared, the MnO@C-HMT-800 stood out. It displayed a mesoporous architecture with a high specific surface area of 1353.1 m 2 g −1 , which facilitates ion transport and energy storage. Additionally, the MnO encapsulated in the carbon layer enables the generation of pesudocapacitance via the redox reaction of Mn 2+ and Mn 3+ . The interaction between the double-layer capacitance of the porous carbon and the pseudocapacitance of the manganese oxides endows the MnO@C-HMT-T composite with superior electrochemical performance. Consequently, the MnO@C-HMT-800 electrode exhibits an impressive specific capacitance of 575.2 F/g at a current density of 1 A/g, demonstrating exceptional stability at 95.6 % after 10,000 cycles. This surpasses the performance of most reported Mn-based materials in the literature. This work presents an innovative and straightforward process for fabricating carbon-encapsulated transition oxides that could be highly valuable in energy storage systems.