Zinc-ion capacitors (ZICs) are a promising and safe energy storage system for portable electronics but usually limited by relatively low areal capacity and energy density. Although increasing the mass loading has been suggested, thick electrode layers and clogged pores unavoidably lead to sluggish electron transport and ion diffusion as well as “dead volume” of active materials. Herein, a millimeter-scale 3D thick-network electrode, composed of closely intertwined hierarchical porous N-doped and free-standing carbon nanofibers (HPNCFs), was fabricated via carbonization of nanoscale zeolitic imidazolate framework (ZIF-8) particles embedded in electrospun polyacrylonitrile (PAN) nanofibers. With fast electron/ion transport, large ion-accessible surface area and high utilization rate of active materials, the mass loading of the HPNCFs electrode can reach 48.67 mg cm with a thickness of 4.46 mm. Moreover, the HPNCFs-based ZICs can yield a superior areal/gravimetric capacity of 4.13 F cm /280 F g, superior rate capability up to 193.7 F g even at 100 A g, high energy density of 99.6 Wh kg, and long-term stability for 40,000 cycles. The straightforward approach can provide an opportunity to prepare efficient thick electrodes that could be applied in electrocatalysis, energy storage/conversion, and other electrochemical energy-related techniques.

中文翻译：

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分层多孔氮掺杂碳纤维可实现超快电子和离子传输，用于高质量负载下的锌离子存储

锌离子电容器（ZIC）是一种用于便携式电子产品的有前途且安全的储能系统，但通常受到相对较低的面积容量和能量密度的限制。尽管有人建议增加质量负载，但厚的电极层和堵塞的孔隙不可避免地会导致电子传输和离子扩散缓慢以及活性材料的“死体积”。在此，通过嵌入电纺聚丙烯腈中的纳米级沸石咪唑酯骨架（ZIF-8）颗粒的碳化制备了毫米级3D厚网络电极，由紧密缠绕的分层多孔氮掺杂和独立碳纳米纤维（HPNCF）组成。 （PAN）纳米纤维。 HPNCFs电极具有快速的电子/离子传输、大的离子可接触表面积和高活性材料利用率，其质量负载可以达到48.67 mg cm，厚度为4.46 mm。此外，基于 HPNCFs 的 ZIC 可以产生 4.13 F cm /280 F g 的卓越面积/重量容量，即使在 100 A g 下也能达到 193.7 F g 的优异倍率能力，99.6 Wh kg 的高能量密度，以及长期的性能。 40,000 次循环的稳定性。这种简单的方法可以提供制备高效厚电极的机会，该电极可应用于电催化、能量存储/转换和其他电化学能量相关技术。