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

Author(s)

Silva, Joao Pedro ; Irikura, Kallyni ; Biaggio, Sonia R. ; Bocchi, Nerilso ; Rocha-Filho, Romeu C.

• Document type: Journal article
• Source: IONICS; v. N/A, p. 12-pg., 2022-06-07.

Abstract

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 epsilon-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. (AU)

• FAPESP's process: 17/12790-7 - Preparation and characterization of TiO2 nanostructured electrodes modified with metal organic frameworks (MOFs) for application in the preconcentration and reduction of CO2
• Grantee: Kallyni Irikura
• Support Opportunities: Scholarships in Brazil - Post-Doctoral