Hydrothermally derived three-dimensional porous hollow double-walled Mn2O3 nanocubes as superior electrode materials for supercapacitor applications

Abstract Although Mn2O3 has been widely used as an electrode material for lithium-ion batteries, it has not been explored as a supercapacitor electrode material due to its low specific area, irregular morphology, low porosity, and low ionic conductivity. Targeting this gap, in this study, we attempted to develop regular and porous hollow double-walled Mn2O3 cubes, which can simultaneously provide a large surface area and enhance charge diffusion to result in a high capacitance. We synthesized cube-like 3D hierarchically porous double-walled Mn2O3 (c-HDW-Mn2O3) using a simple hydrothermal method followed by calcination. The optimized electrode material c-HDW-Mn2O3@9 exhibited excellent capacitance and 90% retention over 3000 consecutive charge-discharge cycles at a fixed current density. Such high performance and good stability can be attributed to the porous and crystalline structure and high surface area of the optimized electrode. Finally, these hierarchically porous nanocubes can be considered as suitable materials for energy-storage applications.