Capacitive Mechanism of Oxygen Functional Groups on Carbon Surface in Supercapacitors

TL;DR

This paper investigates how oxygen functional groups enhance the capacitance of carbon materials in supercapacitors by analyzing their pseudocapacitive behavior and effects on electrochemical properties.

Contribution

It provides a detailed analysis of the mechanisms by which oxygen functional groups improve supercapacitor performance, including pseudocapacitance and impedance effects.

Findings

Oxygen functional groups increase charge capacity during cycling.

Pseudocapacitance is significantly contributed by oxygen groups.

Oxygen groups affect electrochemical impedance characteristics.

Abstract

Oxygen functional groups are one of the most important subjects in the study of electrochemical properties of carbon materials which can change the wettability, conductivity and pore size distributions of carbon materials, and can occur redox reactions. In the electrode materials of carbon-based supercapacitors, the oxygen functional groups have widely been used to improve the capacitive performance. In this paper, we not only analyzed the reasons for the increase of the capacity that promoted by oxygen functional groups in the charge-discharge cycling tests, but also analyzed the mechanism how the pseudocapacitance was provided by the oxygen functional groups in the acid/alkaline aqueous electrolyte. Moreover, we also discussed the effect of the oxygen functional groups in electrochemical impedance spectroscopy.