Construction of CA@MnO2 core-shell heterostructure for supercapacitor applications

Constructing a core-shell structure is an effective way to improve the performance of electrode materials for supercapacitors. The existing core-shell structures frequently confront common issues such as weak interfacial bonding, structural instability at high temperatures, and the difficulty of balancing conductivity and active sites. In this article, we employ a low-temperature liquid-phase method to synthesize manganese oxide (MnO2) coated on carbon aerogel (CA) heterostructure. Mn2+ ions go through the redox reaction under weak alkaline conditions, controllable grow on the surface of carbon aerogels' skeleton, and synthesis a uniform manganese oxide shell layer. CA@MnO2 not only possesses a three-dimensional porous structure but also has an enriched aperture range, and a high specific surface area. Meanwhile, the existence of the MnO2 coating layer can enhance the structural stability of the CA during high-temperature calcination. The core-shell aerogels are applied to supercapacitors and exhibit high specific capacitance (895.0 F/g) and excellent cycling performance. When utilized in the symmetrical double-electrode supercapacitor, it has a wide working voltage range (2.6 V), and high energy density (144.2 Wh/kg) at the power density of 250.0 W/kg, presenting outstanding electro performance. The calculation results indicate the MnO2 shell layer and the CA core have a distinct hetero-interface and strong interactions, which can improve the conductivity and increase the OH adsorption energy. The core-shell heterostructure CA@MnO2 is a promising supercapacitor electrode.