Facile Fabrication and High Supercapacitive Performance of Three-Dimensional Mn/MnO_x Periodic Arrays Architecture

In this paper, 3D-Mn/MnO_x periodic arrays architecture is fabricated through a facile and efficient method. A femtosecond laser is used to generate a 3D conductive network on a metallic manganese surface which also serves as the current collector (3D-Mn), followed by chemical oxidation to form Mn₂O₃ and MnO₂ on the surface of the 3D-Mn. Detailed electrochemical characterization reveals that the 3D-Mn/MnO_x electrode exhibits good rate performance and cycle life, and the assembled 3D-Mn/MnO_x supercapacitor can deliver the highest energy density of 5.6 μWh/cm² at a power density of 21.8 μW/cm². The enhanced performance is attributed to the unique periodic 3D-Mn/MnO_x architecture which largely increases the effective electrode surface area, shortens the electron/ion transportation distance, facilitates electrolyte permeation, and reduces the contact resistance between 3D-Mn and MnO_x. Importantly, MnO_x is formed directly on the 3D-Mn surface, which helps to maintain the structural integrity and mechanical adhesion between each other, and thus is beneficial to long-term electrochemical cycling.