An EQCM investigation of capacitance of MnO2 in electrolytes containing multivalent cations

► The capacitance of MnO2 increases with an increase in the charge of the cation in the electrolyte. ► A maximum specific capacitance of 330 F g−1 is achieved in 0.1 M La(NO3)3 electrolyte. ► The magnitude of mass change is approximately proportional to the atomic weight of the cationic element.