Key Takeaways & Executive Findings
- •• B and N co-doped coal-based activated carbon achieves a high specific capacity of 371.4 mAh g−1 at 1 A g−1 for aqueous zinc-ion capacitors. • The material retains 74% of its initial capacity after 10,000 cycles, demonstrating excellent cycling stability. • Density functional theory calculations reveal that pyridinic N is crucial for enhancing Zn2+ storage and electrochemical reversibility. • This work provides insights for designing high-capacity and ultrafast pseudocapacitive carbon cathodes for ZICs.
Abstract
Aqueous zinc-ion capacitors (ZICs) have significant potential as energy storage systems because of their high specific capacity and superior reliability. Heteroatom-doped carbon materials were known to substantially increase the capacitance of ZICs, however the mechanism remains poorly understood. Coal-based activated carbon was functionalized with B and N to serve as the cathode material in ZICs. This modification gave the material a high specific capacity of 371.4 mAh g−1 at 1 A g−1 and it retained 74% of its initial capacity after 10 000 cycles. Experimental results and density functional theory calculations revealed that pyridinic N plays a crucial role in increasing Zn2+ storage, demonstrating superior electrochemical reversibility. This work gives valuable insight into the design of high-capacity and ultrafast pseudocapacitive carbon cathodes for ZICs.
1. Introduction
The development of sustainable, high-performance energy storage systems is important to address the uneven production and geographic distribution of primary energy sources such as solar and wind energy[1]. To address this challenge, hybrid capacitors have been developed as an advanced electrochemical energy storage system, offering high-rate capability, enhanced energy density, superior power output, and excellent cycling stability. In 2005, Fuji Heavy Industries introduced the concept of the “lithium-ion capacitors (LICs)” with the aim of achieving a synergistic effect that exceeds the sum of its individual components. The LICs consist of a prelithiated graphite anode and an activated carbon cathode[2–4]. However, the shortage of lithium metal and its flammability predicted serious economic risks and environmental problems in the long run. Consequently, researchers began exploring multivalent metal-ion hybrid capacitors based on alternative metals as a viable substitute for LICs. These alternatives include monovalent metals (e.g. Na+, K+) and multivalent metals (e.g. Mg2+, Zn2+, Ca2+, Al3+), which are abundant in the Earth’s crust and offer higher electron transfer per mole of ions. However, devices based on Mg2+, Ca2+ and Al3+ usually show poor electrochemical performance in aqueous electrolytes by generating electrochemically inert by-products passivated at the electrode surface. In contrast, zinc-ion capacitors (ZICs) have excellent reversibility, high stability[5] and high theoretical specific capacity (823 mAh g−1)[6−7]. Meanwhile, the low redox potential of Zn/Zn2+ extends the operating voltage window of the capacitor, thereby increasing energy and power density[8−9]. However, the ZICs still suffer from unsatisfactory charge storage capability and durability due to the sluggish ion-migration kinetics in carbon cathodes. Thus, the design of highly electroactive and robust carbon nanostructures is crucial for achieving superior electrochemical performance in ZICs.
Carbon-based materials have been extensively studied and utilized as cathodes for ZICs owing to numerous advantages that include low cost, environmental friendliness, and tunable structure. Among these materials, coal-based activated carbon (CAC) has garnered significant attention due to its cost-effectiveness and abundant availability. As a carbonaceous material, CAC possesses a wealth of surface functional groups, making it an excellent raw material for high-quality activated carbon[10–12].
Loading authentic research manuscript (Pages 1–5)...
LIU Shuyuan, TIAN Zhen, WANG Yanzhong, ZHOU Rui, ZHENG Zhichao (2025). The doping of coal-based activated carbon with both B and N for use as the cathode of high performance aqueous zinc-ion hybrid capacitors. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2026-41-02-07)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the specific capacity of the B and N co-doped coal-based activated carbon cathode?
The B and N co-doped coal-based activated carbon cathode achieves a high specific capacity of 371.4 mAh g−1 at a current density of 1 A g−1.
How does the cycling stability of this material compare?
The material retains 74% of its initial capacity after 10,000 cycles, indicating excellent long-term cycling stability.
What role does pyridinic nitrogen play in the performance?
Density functional theory calculations reveal that pyridinic N is crucial for enhancing Zn2+ storage and electrochemical reversibility, leading to superior performance.
Why are zinc-ion capacitors considered promising energy storage systems?
Zinc-ion capacitors offer high specific capacity, excellent reversibility, high stability, and a low redox potential for Zn/Zn2+, which extends the operating voltage window and increases energy and power density.
What is the significance of using coal-based activated carbon?
Coal-based activated carbon is cost-effective, abundant, and possesses a wealth of surface functional groups, making it an excellent raw material for high-quality activated carbon cathodes.
Related Technical Papers & Translations
A Novel Approach for Enhanced Brain Tumor Segmentation Using Multimodal MRI and Deep Learning
Brain tumor segmentation from multimodal MRI is crucial for diagnosis and treatment planning. In this study, we propose a novel deep learning framework that integrates structural and functional imaging modalities to improve segmentation accuracy. Our method employs a multi-scale attention mechanism and a hybrid loss function to handle class imbalance and boundary ambiguity. Evaluated on the BraTS benchmark, our approach achieves state-of-the-art performance, with Dice scores of 0.91, 0.87, and 0.84 for whole tumor, core, and enhancing tumor, respectively. Furthermore, we demonstrate the generalizability of our model across different scanners and protocols. Our findings suggest that the proposed method can significantly aid clinical decision-making and surgical planning.
Investigation of coupled acoustic and electrical responses and early warning approaches during re-loading of damaged coal
Initial damage from engineering disturbances in deep coal mining degrades mechanical properties and heightens dynamic-hazard risks, challenging conventional monitoring. This study probes the coupled acoustic-electrical responses of initially damaged coal under reloading and develops a multi-parameter, multi-level dynamic integrated early-warning model. Using a true-triaxial Split Hopkinson Pressure Bar (SHPB) system, we prepared specimens with graded damage by varying static deviatoric stresses and dynamic impacts. Uniaxial compression reloading was conducted with synchronous acoustic emission (AE) and resistivity monitoring. Joint time-domain responses of force, acoustics, and electricity delineated distinct loading stages. Time-frequency features were extracted via Fourier and wavelet transforms; crack architecture was quantified by 3D AE localization and fractal-dimension analysis. Initial damage markedly reduced load-bearing capacity. Resistivity decreased sharply with increasing deviatoric stress, while cumulative AE counts increased strongly. The AE spectrum evolved from bimodal to broadband with low- and high-frequency enhancement. The resistivity spectrum showed progressive bandwidth broadening, energy amplification, and high-frequency advancement. The AE spatial fractal dimension rose significantly during compaction. An integrated warning system combining multiscale entropy fusion, Temporal Convolutional Network (TCN)-Transformer forecasting, recurrence-network analysis, and a Bayesian framework yielded a 28.4 s lead time, offering a theoretical basis and technical pathway for intelligent prevention of dynamic hazards.
Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage
Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.