Rapid microwave-assisted solid-state obtention of Mn3O4 and its electrochemical characterization for application as supercapacitor electrodes

• Autor(a) principal: Silva, João Pedro
• Data de Publicação: 2022
• Outros Autores: Irikura, Kallyni [UNESP], Biaggio, Sonia R., Bocchi, Nerilso, Rocha-Filho, Romeu C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1007/s11581-022-04627-y; http://hdl.handle.net/11449/240200
• topic: Energy storage materials; Microwave solid-state synthesis; Precursor ε-MnO2; Pseudocapacitance; Solid-state reactions; Supercapacitor cathode material

A rapid and facile microwave-assisted method coupled with a mild mechanical treatment is proposed to obtain Mn3O4 with good properties to be used as a supercapacitor material. Mn3O4 was produced by thermal decomposition of ε-MnO2 using microwave irradiation in a practical setup and a domestic microwave oven. XRD results, supported by other physical characterizations such as TG/DTA and FTIR and Raman spectroscopy analyses, attested that Mn3O4 was obtained as a single phase after only 5 min of microwave heating. After submitting an oxide sample to a mild mechanical treatment in an adapted ball-mill setup for 30 min, SEM micrographs and BET analyses revealed a particle size in the range of 200–600 nm and a fivefold increase of the specific surface area. The pseudocapacitive behavior of electrodes prepared with the thus obtained Mn3O4 was analyzed by cyclic voltammetry in a 0.1 mol L–1 Na2SO4 aqueous solution. Galvanostatic charge and discharge tests of these electrodes were performed in the 1.0 to 5.0 A g–1 range in the same electrolyte; at 1.0 A g–1, they presented an initial specific capacitance of about 160 F g–1 and good electrochemical stability up to 5000 cycles.