Ultrasonic-assisted, rapid preparation of mesoporous MnCO3 for electrochemical supercapacitor applications: A novel approach

Accounting for the methods opted in the preparation of nanoscale materials with high surface rea, average pore size and volume needs high energy and time-consuming processes. This work discloses a quick, scalable, and simple co-precipitation method for synthesizing MnCO3 for use in supercapacitors as a working electrode using MnSO4 and (NH4)HCO3 as the manganese and carbonate sources, respectively. As-synthesized sample is subjected to sonication at different periods for evaluating the effect of capacitance and the size of MnCO3 particles. Investigations using X-ray diffraction and X-ray photoelectron spectroscopy proves that MnCO3 can form the rhodochrosite phase and microscopical analyses reveals that nanograins smaller than 10 nm aggregated into spherical particles that were submicron in size. N2 adsorption–desorption isotherm isotherms validates the mesoporosity of MnCO3. The Galvanostatic charge–discharge cycling and cyclic voltammetry techniques examine the capacitance characteristics of mesoporous MnCO3 in both 0.1 Mg(ClO4)2 and Na2SO4 aqueous solutions. Mesoporous MnCO3 delivers a specific capacitance of 188F g−1 and 124F g−1 at a specific current of 0.33 A g−1 in both Mg(ClO4)2 and Na2SO4 aqueous solutions with a loading level of 1.5 mg cm−2. Additionally, mesoporous MnCO3 shows strong rate capability and stable cycle-life over 10,000 cycles. These demonstrates the mesoporous nanomaterials with high surface area and volume can enhance the energy storage capacitance of a supercapacitor.