Tuning the capacitance properties of MnCO3 by choice of the electrolyte

Modifying electrolytes is an effective way of improving the capacitance properties. However, this strategy is not explored much compared to tuning the physicochemical properties of the electrode material. Herein, the capacitance properties of electrodeposited MnCO3 (E-MnCO3) are improved by the choice of aqueous electrolyte. MnCO3 is electrodeposited on stainless steel foil and characterized by XRD, Raman spectroscopy and SEM. The capacitance properties of E-MnCO3 are studied in aqueous solutions of NaClO4, Mg(ClO4)2 and La(ClO4)3. Owing to higher ionic conductivity, lower solution and charger transfer resistance, and an increase in the number of electrochemical active sites per cation adsorption/intercalation, E-MnCO3 delivers higher specific capacitance and better rate capability in La(ClO4)3 than in other electrolytes. The capacitance properties of E-MnCO3 in various electrolyte follow the order: La(ClO4)3 > Mg(ClO4)2 > NaClO4.