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.