Room‐Temperature Solvent‐Free Synthesis of Three‐Dimensional Flower‐Like α‐MnO₂ Microspheres for Supercapacitor Application

Abstract

Constructing manganese oxide nanoparticles with different crystal structures and morphologies is crucial for the development of improved supercapacitors. Here, zero‐dimensional (0D) α‐MnO2 and δ‐MnO2 nanoparticles were first synthesized by an ultra‐simple solvent‐free synthetic strategy. The α‐MnO2 nanoparticles exhibited better performance for supercapacitors than δ‐MnO2 nanoparticles due to a higher specific surface area and accelerated electrical charge transfer. Two‐dimensional (2D) α‐MnO2 nanosheets and three‐dimensional (3D) flower‐like α‐MnO2 microspheres were also fabricated by the inclusion of surfactants to investigate the effects of morphology on electrochemical storage capacity with the assistance of different surfactants. Notably, 3D α‐MnO2 microspheres exhibited enhanced electrochemical properties than 0D α‐MnO2 nanoparticles and 2D α‐MnO2 nanosheets for supercapacitors, and generated a favorable specific capacitance of 212.8 F g−1 at 1 A g−1, primarily originating from high porosity, which allows the full infiltration of electrolytes and the rapid shuttling of ions. This work thus describes a simple strategy for the synthesis of 2D nanosheets and 3D self‐assembled nanostructures of MnO2 for application in supercapacitor development.

Sulfur‐Bridged Bonds Heightened Na‐Storage Properties in MnS Nanocubes Encapsulated by S‐Doped Carbon Matrix Synthesized via Solvent‐Free Tactics for High‐Performance Hybrid Sodium Ion Capacitors

“…[49,50] For decades, our group has been devoted to researching the synthesis of nanomaterials by solid-state chemical reaction strategy. [51][52][53][54][55][56][57][58] This technique concerns mechanochemistry and chemical reaction, could save time cost, reduce the production cost, avoid serious pollution, and using solvents, including room-temperature, middle-temperature, and high-temperature solid-state means. Thus, it may be a fine choice to adopt the solvent-free route for the fabrication of MOFs materials.…”