Rational design of uniformly embedded metal oxide nanoparticles into nitrogen-doped carbon aerogel for high-performance asymmetric supercapacitors with a high operating voltage window

Abstract

We report the design of a high-performance asymmetric supercapacitor (ASC) based on manganese monoxide/carbon aerogel (MnO/NCA) composites as the positive electrode and iron oxide/carbon aerogel (Fe₂O₃/NCA) composites as the negative electrode. The prepared MnO/NCA hybrid composites display a highly interconnected network structure with ultrathin MnO nanoparticles uniformly embedded into the 3D nitrogen-doped carbon matrix. Because of the synergistic effects of the highly conductive carbon aerogel and highly pseudocapacitive metal oxides, the hybrid MnO/NCA electrode exhibits highly effective surface area, greatly enhanced ion transportation, and excellent electrochemical performance, in comparison with other MnO_x-based electrode materials. Matching it with the Fe₂O₃/NCA cathode, the novel ASC devices can achieve a high voltage window of 2.0 V, delivering a remarkable energy density of 48.67 W h kg⁻¹ at a power density of 1000 W kg⁻¹ and still retains 27.39 W h kg⁻¹ at a high power density of 10 kW kg⁻¹, consequently giving rise to stable cycling performance. These encouraging results will provide a fresh route for the design and fabrication of metal oxide@carbon aerogel materials for application in next-generation storage systems.