Enhanced Pseudocapacitive Performance of α-MnO2 by Cation Preinsertion.

Although the theoretical capacitance of MnO2 is 1370 F g-1 based on the Mn3+/Mn4+ redox couple, most of the reported capacitances in literature are far below the theoretical value even when the material goes to nanoscale. To understand this discrepancy, in this work, the electrochemical behavior and charge storage mechanism of K+-inserted α-MnO2 (or KxMnO2… (More)