Liu Pengcheng, Hao Hongchang, Singla Aditya, Vishnugopi Bairav S, Watt John, Mukherjee Partha P, Mitlin David
Materials Science and Engineering Program & Texas Materials Institute (TMI), The University of Texas at Austin, Austin, TX 78712-1591, USA.
School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Angew Chem Int Ed Engl. 2024 Jul 29;63(31):e202402214. doi: 10.1002/anie.202402214. Epub 2024 Jun 24.
Aluminum oxide (AlO) 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/cm-0.5 mAh/cm and 3.0 mA/cm-0.5 mAh/cm. 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.
将氧化铝（AlO）纳米粉末旋涂在商用聚丙烯隔膜的两侧，以在钾金属电池（KMB）中创建人工固体电解质界面（SEI）和人工阴极电解质界面（CEI）。这显著提高了稳定性，包括含普鲁士蓝（PB）阴极的KMB的稳定性。例如，对称电池在0.5 mA/cm-0.5 mAh/cm和3.0 mA/cm-0.5 mAh/cm的电流密度下循环1000次后仍保持稳定。氧化铝改性隔膜促进电解质润湿性并提高离子电导率（0.59对0.2 mS/cm）和迁移数（0.81对0.23）。对循环后的改性阳极进行低温聚焦离子束（cryo-FIB）分析表明，与由散布着孔隙和SEI的金属细丝（枝晶）组成的未改性基线相比，其电沉积物致密且呈平面状。氧化铝改性的CEI还抑制了元素铁的交叉并减少了阴极开裂。金属-SEI相互作用的中尺度模型揭示了固有不均匀性的关键作用，阐明了人工SEI如何影响反应电流分布、电导率和形态稳定性。
