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A Facile Synthesis Strategy for N-Doped Graphene Quantum Dots Electrode Materials: Electrochemical Behaviors and Universal Energy Storage Mechanism

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Pubblicato in:Materials vol. 18, no. 23 (2025), p. 5373-5391
Autore principale: Wang, Yongbo
Altri autori: Dai Shichao, Guo Jinghe, Wang, Yanxiang, Tang, Bo
Pubblicazione:
MDPI AG
Soggetti:
China
Japan
Electrons
Electrodes
Electrode materials
Nitrogen
Capacitance
Computer simulation
Energy storage
Functional groups
Activated carbon
Citric acid
Energy consumption
Composite materials
Ethanol
Carbon black
Electrolytes
Electrochemical analysis
Graphene
Spectrum analysis
Fourier transforms
Ethylenediamine
Microscopy
Controllability
Stability
Quantum dots
Density functional theory
Electronic structure
Morphology
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Abstract:In this paper, a simple hydrothermal approach is employed to prepare nitrogen-doped graphene quantum dots (N-GQDs) with controllable size and structural features, where citric acid and ethylenediamine served as the carbon and nitrogen precursors, respectively. The influence of hydrothermal temperature and duration on the structural features, surface chemistry, and electrochemical behavior of N-GQDs is systematically investigated. The capacitive behavior of N-GQD electrodes exhibits typical pseudocapacitive characteristics, primarily attributed to the surface functional groups. The NG-2 electrode (180 °C, 6 h) demonstrates a specific capacitance of 309.8 F g−1 at 1 A g−1 and maintains 98.1% of its initial capacitance after 8000 cycles, confirming excellent stability. Density functional theory (DFT) results demonstrate that the co-presence of graphitic and pyrrolic nitrogen induces a synergistic modulation of the electronic structure, resulting in improved charge-transfer kinetics and surface reactivity of N-GQDs compared to single-type nitrogen doping. Additionally, NG-2//activated carbon (AC)-asymmetric supercapacitor (ASC) achieves an energy density of 22.5 Wh kg−1 at 500 W kg−1 and maintains outstanding cycling stability. This work provides valuable insights into the design and application of N-GQDs for advanced energy storage devices.
ISSN:1996-1944
DOI:10.3390/ma18235373
Fonte:Materials Science Database