LAUSR

Abstract Achieving high cell potential supercapacitors in aqueous-based electrolytes is an essential step to the development of safe energy storage devices with high energy density. It is well known that the extension of cell potentials is due to the chemisorption of hydrogen in the micropores of activated carbon electrodes in neutral aqueous electrolytes. In this work, we have found that the structural feature, electronic property, and functional group of carbon electrodes do also play important roles to the cell potentials and performances of carbon-based supercapacitors. We employed four different carbons i.e., carbon fiber paper (CFP), functionalized carbon fiber paper (f-CFP), semiconducting macroporous reduced graphene oxide (rGO), and microporous activated carbon (AC) having different morphologies, structures, and functional groups. The symmetrical supercapacitors of AC and rGO show the maximum cell potential of 1.6 V by floating up to 200 h. This indicates that not only does the chemisorption of hydrogen within micropores play a key role on the wide working cell potentials (> 1.23 V) but others also play an important role confirmed by in situ mass spectrometry. This work may be useful for further development of carbon-based supercapacitors.