Preparation of Manganese Oxide Nanoparticles with Enhanced Capacitive Properties Utilizing Gel Formation Method

Development of efficient and environmentally benign materials is important to satisfy the increasing demand for energy storage materials. Nanostructured transition-metal oxides are attractive because of their variety in morphology, high conductivity, and high theoretical capacitance. In this work, the nanostructured MnO2 was successfully fabricated using a gel formation process followed by calcination at 400 degrees C (MNO4) and 700 degrees C (MNO7) in the presence of air. The suitability of the prepared materials for electrochemical capacitor application was investigated using graphite as an electrode substrate. The chemical, elemental, structural, morphological, and thermal characterizations of the materials were performed with relevant techniques. The structural and morphological analyses revealed to be a body-centered tetragonal crystal lattice with a nano-tablet-like porous surface. The capacitive performances of the MNO4- and MNO7modified graphite electrodes were examined with cyclic voltammetry and chronopotentiometry in a 0.5 M Na2SO4 aqueous solution. The synthesized MNO7 demonstrated a higher specific capacitance (627.9 F g(-1)), energy density (31.4 Wh kg(-1)), and power density (803.5 W kg(-1)) value as compared to that of MNO4. After 400 cycles, the material MNO7 preserves 100% of capacitance as its initial capacitance. The highly conductive network of nanotablet structure and porous morphologies of MNO7 are most likely responsible for its high capacitive behavior. Such material characteristics deserve a good candidate for electrode material in energy storage applications.

Automated summary

The development of efficient and environmentally friendly materials for energy storage is crucial. In this study, nanostructured MnO2 was successfully synthesized and its applicability in electrochemical capacitors was investigated. The results showed that the calcinated MNO7 exhibited higher specific capacitance, energy density, and power density compared to MNO4, and its nano-tablet-like structure and porous morphology were attributed to its superior capacitive behavior.