Potassium-ion batteries (PIBs) have gained considerable attention in the past decade because of the rich potassium reserves in our planet. However, the development of anode materials is still a major challenge because of the hard reaction kinetics and poor cycling stability in the insertion/extraction process. Herein, we report interconnected MnCO₃ nanostructures anchored on carbon fibers (MnCO₃/CF) composites as anode for PIBs. The MnCO₃/CF can be directly used as anode on PIBs, avoiding the addition of polyvinylidene fluoride (PVDF) binders and the complicated slurry coating onto copper process. The nanosized MnCO₃ nanostructures are interconnected with each other, which can provide short ions diffusion length during the charge/discharge process. The MnCO₃ nanostructures are firmly anchored on the surface of CF through C–Mn bonds, ensuring cycling stability. Also, the CF with good electronic conductivity guarantees fast electrons transportation in MnCO₃/CF system. Benefiting from the advantageous features mentioned earlier, the MnCO₃/CF anode behaves enhanced potassium storage performance compared with that of pure MnCO₃ anode. The MnCO₃/CF anode delivers a high capacity of 462 mAh/g at 50 mA/g after 100 cycles, whereas the capacity of pure MnCO₃ anode is only 134 mAh/g at 50 mA/g after 80 cycles. This work demonstrates the prospect of metal carbonate as anode materials for PIBs and provides a useful strategy to design advanced anode materials for PIBs.

由于地球上丰富的钾储量，钾离子电池 (PIB) 在过去十年中受到了广泛关注。然而，由于在插入/提取过程中反应动力学和循环稳定性差，负极材料的开发仍然是一个重大挑战。在此，我们报告了锚定在碳纤维（MnCO ₃ /CF）复合材料上的互连的 MnCO ₃纳米结构作为 PIB 的阳极。MnCO ₃ /CF 可直接用作 PIB 上的阳极，避免了添加聚偏二氟乙烯 (PVDF) 粘合剂和在铜工艺上进行复杂的浆料涂覆。纳米级 MnCO ₃纳米结构相互连接，可以在充电/放电过程中提供较短的离子扩散长度。MnCO ₃纳米结构通过C-Mn键牢固地锚定在CF表面，确保循环稳定性。此外，具有良好电子导电性的CF保证了MnCO ₃ /CF体系中电子的快速传输。得益于前面提到的有利特性，与纯MnCO _{3阳极相比，MnCO 3} /CF 阳极表现出增强的钾储存性能。MnCO ₃ /CF 阳极在 50 mA/g 循环 100 次后提供 462 mAh/g 的高容量，而纯 MnCO _3的容量在 80 次循环后，阳极在 50 mA/g 时仅为 134 mAh/g。这项工作展示了金属碳酸盐作为 PIBs 负极材料的前景，并为设计先进的 PIBs 负极材料提供了有用的策略。