Potassium–iodine batteries show great promise as alternatives for next-generation battery technology, owing to their high power density and environmental sustainability. Nevertheless, they suffer from polyiodide dissolution and the multistep electrode fabrication process, which leads to severe performance degradation and limitations in mass-market adoption. Herein, we report a simple “solution–adsorption” strategy for scale-up production of Ti₃C₂(OH)_x-wrapped carbon nanotube paper (CNP), as an economic host for strengthening the iodine encapsulation. The cutting-edge characterizations and theoretical calculation results reveal that CNP exhibits great affinity to the electrochemically active I₃^–/I^– redox couple, while the Ti–OH functional groups on MXene restrict the dissolution of polyiodides through forming the stable I···H–O intramolecular halogen bond. Benefiting from such a synergistic effect, the free-standing electrode ensures the reversible redox chemistry for developing high-performing potassium–iodine batteries. The fabricated pouch cell (100 mAh) shows a high energy density (130 Wh kg^–1) with a full charge/discharge of 10 min, outperforming state-of-the-art new battery systems that require both high energy/power density. Such a potassium–iodine battery reduces the cost to 255 US$ kW h^–1, which is much lower than that of the cathode materials in lithium-ion batteries and offers a sustainable option for grid-scale energy storage.

中文翻译：

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稳健的 I···H–O 分子内卤素键促进可持续钾碘电池的可逆 I3–/I– 氧化还原行为


钾碘电池由于其高功率密度和环境可持续性，有望成为下一代电池技术的替代品。然而，它们会受到聚碘化物溶解和多级电极制造工艺的影响，这会导致严重的性能下降并限制大众市场的采用。在此，我们报道了一种简单的“溶液-吸附”策略，用于扩大生产 Ti₃C₂（OH）_x 包裹的碳纳米管纸 （CNP），作为加强碘封装的经济主体。前沿表征和理论计算结果表明，CNP 对电化学活性的 I₃^–/I^– 氧化还原对表现出很大的亲和力，而 MXene 上的 Ti–OH 官能团通过形成稳定的 I···H-O 分子内卤素键。受益于这种协同效应，独立式电极确保了可逆的氧化还原化学，用于开发高性能钾碘电池。制造的软包电池 （100 mAh） 显示出高能量密度 （130 Wh kg^–1），完全充电/放电时间为 10 分钟，优于需要高能量/功率密度的最先进的新型电池系统。这种钾碘电池将成本降低到 255 美元 kW ^h-1，远低于锂离子电池中的正极材料，并为电网规模的储能提供了可持续的选择。