MnCO3: a novel electrode material for supercapacitors

Abstract

In this manuscript, MnCO₃ is introduced as a novel electrode material for supercapacitors. MnCO₃ was synthesized by a hydrothermal method using KMnO₄ and commercial sugar as precursors. The synthesized product was characterized by powder X-ray diffraction, SEM, TEM and Raman spectroscopic studies. Rietveld refinement of powder X-ray diffraction confirmed the formation of a pure phase of MnCO₃. Microscopic studies revealed particles of different shapes with sizes varying from 0.1 to 0.3 μm. Elemental mapping demonstrated a uniform distribution of manganese, carbon, and oxygen and there are no other impurity elements observed. The capacitive storage performance of MnCO₃ was evaluated in three different electrolytes, namely, 0.1 M Na₂SO₄, 0.1 M Mg(ClO₄)₂ and 6 M KOH by cyclic voltammetry and galvanostatic charge–discharge cycling. A high specific capacitance of 216 F g⁻¹ was obtained at a high loading level of 1.5 mg cm⁻² for submicron sized particles of MnCO₃ in a 0.1 M Mg(ClO₄)₂ electrolyte. Good reversibility, high coulombic efficiency, respectable rate performance and long cycle-life are also reported for MnCO₃. This study opens up ample avenues to explore a new class of carbonate based materials for supercapacitor applications.