Functionalized graphene with both physical and chemical adsorptions of charges for high-performance supercapacitors

Jinzhang Liu,* Yi Zhao
School of Materials Science and Engineering, Beihang University, Beijing 100191, China
Nano-Micro Conference, 2017, 1, 01036
Published Online: 24 October 2017 (Abstract)
DOI:10.11605/cp.nmc2017.01036
Corresponding Author. Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

How to Cite

Citation Information: Jinzhang liu, Yi Zhao, Functionalized graphene with both physical and chemical adsorptions of charges for high-performance supercapacitors. Nano-Micro Conference, 2017, 1, 01036 doi: 10.11605/cp.nmc2017.01036

History

Received: 26 May 2017, Accepted: 17 June 2017, Published Online: 24 October 2017

Abstract

Carbon-based supercapacitor is also called electric double-layer capacitor that store energy via physical adsorption and desorption of ions from the electrolyte. Pseudocapacitors based on metal oxides or conductive polymers store energy via a redox process and generally have higher specific capacitance compared to the EDL type. Graphene has been regarded as an ideal candidate for supercapacitor applications, while the specific capacitance achieved so far in the lab, normally 200-300 F/g, is much lower than its theoretical value of 550 F/g. In order to enhance the charge storage capacity of graphene, we functionalized reduced graphene oxide by N-doping and adsorption of small molecules of hydrolysized polyimide (PI). In N-doped graphene, the N-O bonds are responsible for the enhanced capacitance owing to their pseudo capacitive property [1]. Further, we found that the hydrolysis of PI can release small molecules into water solution, and these aromatic molecules adsorbed onto graphene via π-π interaction have a significant effect in increasing the capacitance. With merely 3% weight increase after adsorption, the specific capacitance is about 40% increased. High capacitance over 420 F/g can be easily achieved from the functionalized graphene electrode in H2SO4 aqueous electrolyte, even the electrode has high mass loading around 5 mg/cm2. In Li2SO4 aqueous electrolyte that can extend the operation voltage window to 1.6 V, the specific capacitance also remains high around 400 F.

Fig1

Figure 1. (a) Comparison to the electrochemical performance of N-doped graphene electrode before and after adsorption of hydrolysized PI molecules. (a) CV curves. (b) Capacitance Vs. discharging current density in galvanostatic CD measurement.

 

References

[1] T. Lin; I.-W. Chen; F. Liu; C. Yang; H. Bi; F. Xu; F. Huang. Nitrogen-doped mesoporous carbon of extraordinary capacitance for electrochemical energy storage. Science. 350, 1508-1513 (2015). doi:10.1126/science.aab3798

Open Access

This article is licensed under a Creative Commons Attribution 4.0 International License. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
© The Author(s) 2017

[1] T. Lin; I.-W. Chen; F. Liu; C. Yang; H. Bi; F. Xu; F. Huang. Nitrogen-doped mesoporous carbon of extraordinary capacitance for electrochemical energy storage. Science. 350, 1508-1513 (2015). doi:10.1126/science.aab3798

 

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