The Origin of Improved Electrical Double‐Layer Capacitance by Inclusion of Topological Defects and Dopants in Graphene for Supercapacitors

Abstract

Low-energy density has long been the major limitation to the application of supercapacitors. Introducing topological defects and dopants in carbon-based electrodes in a supercapacitor improves the performance by maximizing the gravimetric capacitance per mass of the electrode. However, the main mechanisms governing this capacitance improvement are still unclear. We fabricated planar electrodes from CVD-derived single-layer graphene with deliberately introduced topological defects and nitrogen dopants in controlled concentrations and of known configurations, to estimate the influence of these defects on the electrical double-layer (EDL) capacitance. Our experimental study and theoretical calculations show that the increase in EDL capacitance due to either the topological defects or the nitrogen dopants has the same origin, yet these two factors improve the EDL capacitance in different ways. Our work provides a better understanding of the correlation between the atomic-scale structure and the EDL capacitance and presents a new strategy for the development of experimental and theoretical models for understanding the EDL capacitance of carbon electrodes.

Density Functional Theory Calculations of the Quantum Capacitance of Graphene Oxide as a Supercapacitor Electrode

“…Thus, the deficiency in either of the individual components can limit the total interfacial capacitance. Double‐layer capacitance ( ), which mostly relies on the accessible surface area of the electrode in contact with electrolyte ions, highly depends on electrode morphology ,. Graphene oxide usually have a relatively broad interlayer spacing because oxygen‐containing groups can prevent graphene sheet aggregation to some degree.…”

Effects of Intrinsic Pentagon Defects on Electrochemical Reactivity of Carbon Nanomaterials

“…[10] Hence,t he pentagon defects could possess excellent electrocatalytic activity and may be the potential active sites.S imultaneously,t he generation of intrinsic carbon defects can bring about abundant pore structures and result in the enhanced specific surface area, thereby accelerating the mass and charge transfer in ORR processes or supercapacitors. [11] Moreover,t he heteroatom dopants,especially nitrogen doping, are universally acknowledged to be the extremely efficient means to promote the electrochemical properties of carbon materials according to previous reports. [12] Herein, to confirm the effect of intrinsic pentagon defects on the electrochemical properties of carbon nanomaterials, density functional theory (DFT) calculations were first employed.…”

Recent Advances in Growth and Modification of Graphene‐Based Energy Materials: From Chemical Vapor Deposition to Reduction of Graphene Oxide

“…The N‐doped CVD‐graphene with pyrrolic and pyridinic configurations had better performance than other configurations, showing a fivefold enhancement in measured capacitance over that of pristine graphene. Afterward, Chen et al found that the increase of defect concentration in CVD‐graphene showed positive effect on capacitance . These operations deal with CVD‐graphene to improve device performances without the transformation of energy storage mechanism.…”