With high theoretical capacity, tin phosphide (Sn₄P₃) has recently garnered attention as the anode for potassium-ion batteries (PIBs). However, its application is limited by the rapid capacity decay, which is highly correlated with the stability of solid electrolyte interphase (SEI). Here, we explore how the solvation structure of electrolytes affects the interphase components for the Sn₄P₃ anode, thus determining the cycle stability. The decomposition of FSI⁻ and ester solvents, particularly EC, may result in the SEI layer being enriched with poly(CO₃) and K-F, leading to a more stable cycling capability of K/Sn₄P₃ batteries in the KFSI-EC:DMC:EMC electrolyte. Moreover, a compact and uniform SEI layer promotes cycle stability. Theoretical analysis of the solvation structure epitomizes that the KFSI-EC:DMC:EMC electrolyte can generate a stable SEI layer due to K⁺ interacting more with FSI⁻ anions and EC solvent. The finding of this work helps us comprehend how SEI layer components affect the capacity of Sn₄P₃ anodes in PIBs.

具有高理论容量的磷化锡（Sn ₄ P ₃）最近作为钾离子电池（PIB）的负极而受到关注。然而，其应用受限于快速的容量衰减，这与固体电解质界面（SEI）的稳定性高度相关。在这里，我们探讨了电解质的溶剂化结构如何影响 Sn ₄ P ₃负极的相间成分，从而决定循环稳定性。FSI ^-和酯溶剂，特别是 EC 的分解可能导致 SEI 层富含聚 (CO _{3 ) 和 KF，从而导致 K/Sn 4} P ₃的循环能力更稳定KFSI-EC:DMC:EMC 电解液中的电池。此外，致密且均匀的 SEI 层可提高循环稳定性。^{溶剂化结构的理论分析表明，由于 K +}与 FSI ^-阴离子和 EC 溶剂的相互作用更多， KFSI-EC:DMC:EMC 电解质可以产生稳定的 SEI 层。这项工作的发现有助于我们理解 SEI 层成分如何影响 PIB 中 Sn ₄ P ₃阳极的容量。