An unstable cathode–electrolyte interface leads to a continuous decomposition of the electrolyte and low Coulombic efficiency, resulting in rapid capacity degradation. A stable cathode–electrolyte interface chemistry engineering was thus employed to achieve the highly stable K_0.5MnO₂ as a cathode for potassium-ion batteries (PIBs). Theoretical calculations and experimental results show that carbonate electrolyte of potassium bis(fluorosulfonyl)imide (KFSI) in ethyl methyl carbonate (EMC) can facilitate the realization of anion-dominated interfacial behavior and the construction of a stable cathode electrolyte interphase (CEI) film with uniform inorganic/organic compositions. It can accelerate the K⁺ solvation–desolvation process and induce the formation of a stable CEI with more inorganic components, contributing to the stable and fast charge/ions transfer kinetics. The designed electrolyte provides new insights for enhancing the stability of a layered oxide cathode, which is of great significance for promoting the development of cathodes for PIBs.

中文翻译：

---

面向钾离子电池层状结构氧化物的界面化学工程


不稳定的阴极-电解质界面导致电解质持续分解和库仑效率低，从而导致容量快速退化。因此，采用稳定的阴极-电解质界面化学工程来实现高度稳定的 K_0.5MnO₂ 作为钾离子电池 （PIB） 的阴极。理论计算和实验结果表明，在碳酸甲乙酯 （EMC） 中，双（氟磺酰）酰亚胺钾 （KFSI） 的碳酸盐电解质有助于实现阴离子主导的界面行为，并构建具有均匀无机/有机成分的稳定阴极电解质界面 （CEI） 膜。它可以加速 K⁺ 溶剂化-脱溶剂化过程，并诱导形成具有更多无机成分的稳定 CEI，有助于稳定和快速的电荷/离子转移动力学。所设计的电解质为增强层状氧化物正极的稳定性提供了新的见解，对促进 PIBs 正极的发展具有重要意义。