Abstract Potassium-ion batteries (PIBs) have attracted great interest due to their high-energy-density and low-cost. The lack of stable anode material greatly limits the quick development of PIBs. Phosphorus-metal compounds are regarded as a class of materials with promising prospects as anode material for PIBs with a low operating voltage and high conductivity. Among them, due to the challenging synthesis method, the application of SnP is limited. Herein, a facile approach to synthesize trigonal SnP@C through alloying red phosphorus with tin on carbon material is reported. It is found that carbon substrate can largely reduce vibrational and configurational entropies, playing a critical role on the formation of metastable SnP. When applied as anode in PIBs, the SnP@C composite delivers a high reversible capacity of 478.1 mAh·g−1 at 50 mA g−1 and a stable cycling performance at 1000 mA g−1. The good electrochemical performance is associated with the SnP@C as well as the carbon, which could suppress the phase separation during charge/discharge process to maintain structural stability. This work may open a new avenue for low-cost synthesis of metastable phases for advanced energy storage systems.

中文翻译：

---

亚稳三角SnP：一种很有前途的钾离子电池负极材料

摘要 钾离子电池（PIBs）因其能量密度高、成本低而备受关注。缺乏稳定的负极材料极大地限制了 PIBs 的快速发展。磷金属化合物被认为是一类具有广阔前景的低工作电压和高电导率的PIBs负极材料。其中，由于合成方法具有挑战性，SnP的应用受到限制。本文报道了一种通过将红磷与锡碳材料合金化来合成三角形 SnP@C 的简便方法。研究发现，碳基底可以在很大程度上降低振动和构型熵，对亚稳态 SnP 的形成起着关键作用。当用作 PIB 中的阳极时，SnP@C 复合材料可提供 478 的高可逆容量。在 50 mA g-1 下为 1 mAh·g-1，在 1000 mA g-1 下具有稳定的循环性能。良好的电化学性能与 SnP@C 以及碳有关，可以抑制充放电过程中的相分离，以保持结构稳定性。这项工作可能为先进储能系统的亚稳态相的低成本合成开辟了一条新途径。