Volume 9, Issue 7 2402038
Research Article

Selective Nitrogen Doping at Hole Edges of Holey Graphene: Enhancing Ionic Transport Mechanisms for High-Performance Supercapacitors

John Peter Isaqu

John Peter Isaqu

Graduate Institute of Energy Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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Chun-Wei Huang

Chun-Wei Huang

Graduate Institute of Energy Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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Jui-Kung Chih

Jui-Kung Chih

Graduate Institute of Energy Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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Bo Yan Huang

Bo Yan Huang

Department of Chemical and Materials Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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Mohanapriya Subramani

Mohanapriya Subramani

Department of Chemical and Materials Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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I-Yu Tsao

I-Yu Tsao

Institute of Materials Science and Engineering, National Central University, Tao-Yuan, 32001 Taiwan

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Bor Kae Chang

Corresponding Author

Bor Kae Chang

Department of Chemical and Materials Engineering, National Central University, Tao-Yuan, 32001 Taiwan

E-mail: [email protected]; [email protected]

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Ching Yuan Su

Corresponding Author

Ching Yuan Su

Graduate Institute of Energy Engineering, National Central University, Tao-Yuan, 32001 Taiwan

Department of Mechanical Engineering, National Central University, Tao-Yuan, 32001 Taiwan

E-mail: [email protected]; [email protected]

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First published: 24 March 2025

Abstract

Developing highly holey graphene with controllable doping enhances ionic transport and conductivity, boosting the performance of energy storage devices like supercapacitors. However, the method for precise site-selective doping and the effects of heterogeneous atomic doping at pore edges on ion transport remain not fully understood. This study presents a method to achieve precisely and selectively high nitrogen doping (N-doping) at the hole edges of porous graphene (N-EHG) through a two-step process. Compared to untreated graphene (HG) and basal plane-doped graphene (N-BHG), N-EHG demonstrates superior charge storage capacity and ionic conductivity. Analyzing the porous structure, size distribution, and hydrophilicity influenced by the carbon–oxygen ratio, N-EHG shows a specific surface area of 509 m2 g−1, significantly higher than HG's 100 m2 g−1. Electrochemical results revealed that N-BHG and N-EHG achieved high gravimetric capacitances of 482.3 and 624.4 F g−1, respectively, due to enhanced ion diffusion, exceeding HG by ≈12- and 15.6-fold. Furthermore, the assembled coin-cell retains over 99% capacitance after 15,000 cycles, demonstrating exceptional stability. Both N-EHG and N-BHG show diffusion-governed charge storage, with N-EHG benefitting further from edge-state N-doping. Density Functional Theory (DFT) calculations reveal a lower energy barrier for ion diffusion and strong K⁺ adsorption on edge pyridinic-N, where increased electrode charge creates a negative center on N-dopants, enhancing K⁺ binding. These findings underscore the potential of edge-state N-doping in holey graphene for advanced energy storage applications.

Conflict Of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

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