Potassium ion battery (PIB) is a potential candidate for future large-scale energy storage. A key challenge is that the (de)potassiation stability of graphitic carbon anodes is hampered by the limited (002) interlayer spacing. Amorphous carbon with a hierarchical structure can buffer the volume change during repeated (de)potassiation and enable stable cycling. Herein, a direct pyrolysis approach is demonstrated to synthesize a highly nitrogen-doped (26.7 at.%) accordion-like carbon anode composed of thin carbon nanosheets and a turbostratic crystalline structure. The hierarchical structure of accordion-like carbon is endowed by a self-assembly process during pyrolysis carbonization. The hierarchical nitrogen-doped accordion structure enables a high reversible capacity of 346 mAh g⁻¹ and superior cycling stability. This work constitutes a general synthesis methodology that can be used to prepare hierarchical carbon anodes for advanced PIBs.

中文翻译：

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具有高氮掺杂的手风琴状碳，可实现快速稳定的 K 离子存储

钾离子电池（PIB）是未来大规模储能的潜在候选者。一个关键的挑战是石墨碳阳极的（去）钾化稳定性受到有限的（002）层间距的阻碍。具有分级结构的无定形碳可以缓冲重复（脱）钾过程中的体积变化并实现稳定循环。在此，证明了直接热解方法可以合成由薄碳纳米片和乱层晶体结构组成的高度氮掺杂 (26.7 at.%) 的手风琴状碳阳极。手风琴状碳的分级结构是由热解碳化过程中的自组装过程赋予的。分级氮掺杂手风琴结构可实现 346 mAh g ^-1的高可逆容量和优越的循环稳定性。这项工作构成了一种通用的合成方法，可用于制备高级 PIB 的分级碳阳极。