Zhang Tianyi, Yuan Ning, Li Zijie, Chao Kun, Zhang Zhonghua, Li Guicun
College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, China.
Molecules. 2024 Jun 24;29(13):2996. doi: 10.3390/molecules29132996.
Rechargeable potassium ion batteries have long been regarded as one alternative to conventional lithium ion batteries because of their resource sustainability and cost advantages. However, the compatibility between anodes and electrolytes remains to be resolved, impeding their commercial adoption. In this work, the K-ion storage properties of Bi nanoparticles encapsulated in N-doped carbon nanocomposites have been examined in two typical electrolyte solutions, which show a significant effect on potassium insertion/removal processes. In a KFSI-based electrolyte, the N-C@Bi nanocomposites exhibit a high specific capacity of 255.2 mAh g at 0.5 A g, which remains at 245.6 mAh g after 50 cycles, corresponding to a high capacity retention rate of 96.24%. In a KPF-based electrolyte, the N-C@Bi nanocomposites show a specific capacity of 209.0 mAh g, which remains at 71.5 mAh g after 50 cycles, corresponding to an inferior capacity retention rate of only 34.21%. Post-investigations reveal the formation of a KF interphase derived from salt decomposition and an intact rod-like morphology after cycling in K2 electrolytes, which are responsible for better K-ion storage properties.
由于其资源可持续性和成本优势，可充电钾离子电池长期以来一直被视为传统锂离子电池的一种替代品。然而，负极与电解质之间的兼容性仍有待解决，这阻碍了它们的商业应用。在这项工作中，研究了封装在氮掺杂碳纳米复合材料中的铋纳米颗粒在两种典型电解质溶液中的钾离子存储性能，这对钾离子的嵌入/脱出过程有显著影响。在基于双（三氟甲基磺酰）亚胺钾（KFSI）的电解质中，氮掺杂碳@铋（N-C@Bi）纳米复合材料在0.5 A g下表现出255.2 mAh g的高比容量，50次循环后仍保持在245.6 mAh g，对应96.24%的高容量保持率。在基于六氟磷酸钾（KPF）的电解质中，N-C@Bi纳米复合材料的比容量为209.0 mAh g，50次循环后降至71.5 mAh g，对应仅34.21%的较差容量保持率。后续研究揭示了在K2电解质中循环后由盐分解产生的KF界面相的形成以及完整的棒状形态，这是其具有更好钾离子存储性能的原因。
