Facile Synthesis of α-MnO2 with a 3D Staghorn Coral-like Micro-Structure Assembled by Nano-Rods and Its Application in Electrochemical Supercapacitors

Abstract

Abstract:Manganese oxides with an alpha crystal structure are synthesized via combined solid-state reaction and wet chemical processing, which is a simple and inexpensive synthetic route easy for mass production. The effects of the synthetic reaction duration and the temperature of acid treatments on crystal structure, morphology, and electrochemical capacitive properties of α-MnO 2 are discussed. It is evidenced that the samples treated in acid for a longer time at 25 • C display the uniform nanorods that are aggregated to form micro-buildings with fine features on the surface of rods. This microstructure possesses large surface areas and more active sites that are easy to access electrochemically, leading to a better electrochemical capacitive performance. We expected that these results would provide the practical information for shape-and morphology-controlled synthesis for nanostructured functional materials in supercapacitor applications.

α-MnO2 Nanowire Structure Obtained at Low Temperature with Aspects in Environmental Remediation and Sustainable Energy Applications

“…The differences in the diffraction peak intensities for brown and black α-MnO 2 were reported as well in other studies, which were associated with different degrees of crystallinity and/or particle size of the compounds. Based on the literature, the properties of the α-MnO 2 are affected by the physical treatments applied in the synthesis, such as lyophilization, drying, mechanical stirring, and maceration [33,34].…”

Fabrication and tribological behavior of MnO2/epoxy nanocomposites

“…Many researchers have concentrated on the fabrication of MnO 2 -based electrodes with a large surface area for ion and electron movement. [36][37][38][39][40][41][42] They used a variety of synthesis methods, including hydrothermal synthesis, oxidation and reduction synthesis, sol-gel synthesis, chemical precipitation synthesis, chemical self-assembly synthesis, reflux synthesis, and green synthesis. [34][35][36][37][38][39][40][41][42][43] A single-step approach was developed by Kai et al to synthesize the MnO 2 monosheets, by the chemical oxidation of Mn 2+ ions at room temperature.…”

“…[36][37][38][39][40][41][42] They used a variety of synthesis methods, including hydrothermal synthesis, oxidation and reduction synthesis, sol-gel synthesis, chemical precipitation synthesis, chemical self-assembly synthesis, reflux synthesis, and green synthesis. [34][35][36][37][38][39][40][41][42][43] A single-step approach was developed by Kai et al to synthesize the MnO 2 monosheets, by the chemical oxidation of Mn 2+ ions at room temperature. 44 Wang et al used a simple solution technique to make MnO 2 nanosheets at room temperature.…”

Potential of MnO2‐based composite and numerous morphological for enhancing supercapacitors performance

“…Figure 4 shows various MnO 2 morphologies to create supercapacitors and reveals an electrochemical performance improvement whenever morphological alterations are made from one form to another. 131 (B) nanoflower, 132 (C) urchin-like, 133 (D) nanorods, 134 (E) staghorn coral shape, 135 (F) nanorods, 136 (G) flower-like, 136 (H) honeycomb-like, 137 and (I) nanofiber. 138…”