Investigation on cycling stability of Mn-containing oxide supercapacitors
Journal
ECS Transactions
Journal Volume
3
Journal Issue
37
Pages
11-15
Date Issued
2007
Author(s)
Abstract
The mechanism leading to capacitance fading upon cycling of MnO2·nH2O and MnFe2O4 supercapacitors have been studied by using electrochemical characterization and in-situ synchrotron X-ray diffraction. For both supercapacitors, the cycling stability was found to be significantly increased by either reducing charge/discharge rate or increasing dilution ratio with acetylene carbon additive in the electrode. In addition, MnFe2O4 exhibits smaller volume variation during charge/discharge, and its electrodes show superior cycling stability than the MnO2·nH2O ones. It is proposed that the capacitance fading mainly arises from mechanical failure of the electrode structure caused by the volume variation-induced stress, leading to losing contact between the oxide particles and conducting acetylene black and/or detachment of the oxide particles from the electrode matrix.
Type
conference paper