Aluminum oxide (Al2O3) nanopowder is spin‐coated onto both sides of commercial polypropene separator to create artificial solid‐electrolyte interphase (SEI) and artificial cathode electrolyte interface (CEI) in potassium metal batteries (KMBs). This significantly enhances the stability, including of KMBs with Prussian Blue (PB) cathodes. For example, symmetric cells are stable after 1,000 cycles at 0.5 mA/cm2 ‐ 0.5 mAh/cm2 and 3.0 mA/cm2 ‐ 0.5 mAh/cm2. Alumina modified separators promote electrolyte wetting and increase ionic conductivity (0.59 vs. 0.2 mS/cm) and transference number (0.81 vs. 0.23). Cryo‐stage focused ion beam (cryo‐FIB) analysis of cycled modified anode demonstrates dense and planar electrodeposits, versus unmodified baseline consisting of metal filaments (dendrites) interspersed with pores and SEI. Alumina‐modified CEI also suppresses elemental Fe crossover and reduces cathode cracking. Mesoscale modeling of metal – SEI interactions captures crucial role of intrinsic heterogeneities, illustrating how artificial SEI affects reaction current distribution, conductivity and morphological stability.

中文翻译：

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氧化铝 - 钾金属电池中稳定的 SEI 和 CEI


将氧化铝 (Al2O3) 纳米粉末旋涂到商用聚丙烯隔膜的两侧，以在钾金属电池 (KMB) 中形成人造固体电解质界面 (SEI) 和人造阴极电解质界面 (CEI)。这显着增强了稳定性，包括具有普鲁士蓝 (PB) 阴极的 KMB。例如，对称电池在 0.5 mA/cm2 - 0.5 mAh/cm2 和 3.0 mA/cm2 - 0.5 mAh/cm2 下循环 1,000 次后保持稳定。氧化铝改性隔膜可促进电解质润湿并提高离子电导率（0.59 vs. 0.2 mS/cm）和迁移数（0.81 vs. 0.23）。循环修饰阳极的冷冻级聚焦离子束 (cryo-FIB) 分析显示出致密且平面的电沉积，而未修饰的基线则由散布着孔隙和 SEI 的金属丝（枝晶）组成。氧化铝改性的 CEI 还可以抑制元素 Fe 交叉并减少阴极裂纹。金属-SEI相互作用的介观建模捕捉了内在异质性的关键作用，说明了人工SEI如何影响反应电流分布、电导率和形态稳定性。