Self-supporting electrode materials play a pivotal role in advancing the progress of flexible potassium-ion batteries (PIBs). However, crafting self-supporting electrodes with unique compositions and structures to surmount the volume effect and sluggish kinetics resulting from the significant size of K⁺ during potassium storage continues to pose a formidable challenge. In this study, we introduce a novel approach by uniformly encapsulating heterostructured hollow ZnSe/NiSe microspheres within N-doped carbon nanofibers (ZnSe/NiSe@NC) to create freestanding anodes for PIBs. Leveraging its sophisticated composition and structure, the ZnSe/NiSe@NC electrode demonstrates a high initial Coulombic efficiency, substantial reversible capacities, exceptional rate capability, and extended cycling stability, surpassing the performance of most previously reported anodes for PIBs. We elucidate the mechanism behind its high potassium storage capacity through in situ XRD and ex situ TEM measurements, shedding light on the charge storage behavior and mass transfer kinetics using various electrochemical techniques, thus demonstrating its superior rate performance. Theoretical calculations further elucidate the intrinsic mechanism of the heterostructured material in facilitating K-ion adsorption and diffusion. Moreover, we have successfully integrated this designed electrode into full cells, unexpectedly yielding high energy and power densities. Notably, the foldable soft-packed cell we fabricated maintains a high capacity and cycling stability even under high current densities, showcasing its potential for flexible device applications. This research contributes significantly to advancing the rational design, fabrication, and utilization of freestanding electrodes in PIBs and beyond.

中文翻译：

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将空心 ZnSe/NiSe 微球限制在独立式碳纳米纤维中用于柔性钾离子电池

自支撑电极材料在推动柔性钾离子电池（PIB）的进步中发挥着关键作用。然而，制作具有独特成分和结构的自支撑电极，以克服钾存储过程中因 K ⁺尺寸较大而导致的体积效应和缓慢动力学仍然是一项艰巨的挑战。在这项研究中，我们引入了一种新颖的方法，将异质结构空心 ZnSe/NiSe 微球均匀封装在 N 掺杂碳纳米纤维 (ZnSe/NiSe@NC) 中，为 PIB 创建独立式阳极。利用其复杂的成分和结构，ZnSe/NiSe@NC 电极表现出较高的初始库仑效率、显着的可逆容量、出色的倍率性能和延长的循环稳定性，超越了大多数先前报道的 PIB 阳极的性能。我们通过原位XRD 和异位TEM 测量阐明了其高钾存储容量背后的机制，利用各种电化学技术揭示了电荷存储行为和传质动力学，从而证明了其优越的倍率性能。理论计算进一步阐明了异质结构材料促进钾离子吸附和扩散的内在机制。此外，我们已经成功地将这种设计的电极集成到全电池中，出乎意料地产生了高能量和功率密度。值得注意的是，我们制造的可折叠软包装电池即使在高电流密度下也能保持高容量和循环稳定性，展示了其在柔性设备应用中的潜力。这项研究对于推进 PIB 及其他领域独立式电极的合理设计、制造和利用做出了重大贡献。