Charge storage mechanisms of manganese oxide nanosheets and N-doped reduced graphene oxide aerogel for high-performance asymmetric supercapacitors.

ABSTRACT: Although manganese oxide- and graphene-based supercapacitors have been widely studied, their charge storage mechanisms are not yet fully investigated. In this work, we have studied the charge storage mechanisms of K-birnassite MnO₂ nanosheets and N-doped reduced graphene oxide aerogel (N-rGO_ae) using an in situ X-ray absorption spectroscopy (XAS) and an electrochemical quart crystal microbalance (EQCM). The oxidation number of Mn at the MnO₂ electrode is +3.01 at 0 V vs. SCE for the charging process and gets oxidized to +3.12 at +0.8 V vs. SCE and then reduced back to +3.01 at 0 V vs. SCE for the discharging process. The mass change of solvated ions, inserted to the layers of MnO₂ during the charging process is 7.4 μg cm^-2. Whilst, the

SUBMITTER: Iamprasertkun P 

PROVIDER: S-EPMC5114613 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature