Anomalous effect of K ions on electrochemical capacitance of amorphous MnO2

Abstract. Six samples of α-MnO2 with different K ion contents are synthesized by using KMnO4 and Mn(CH3COO)2$4H2O with different pH values at room temperature. The samples are labeled as Mx where x denotes the pH value. The anomalous effect of K ion content on the electrochemical capacitance properties of amorphous MnO2 is investigated systematically. It is found that with the increase of …