The design of monovalent cation selective membranes for precise separation requires a comprehensive understanding of the geometry and chemical environment of the transport channels. Here, a charged cation transfer channel with sub‐1‐nanometer is constructed by layer‐by‐layer self‐assembly of layered double hydroxides. To effectively improve the separation performance, the thickness of the membrane and the separation performance test temperature are explored. The enhanced size confinement effect and wall Coulomb interaction lead to better migration of K+/Na+ than of Li+, which allows the selectivity of K+/Li+ or Na+/Li+ as 5.7 and 4.0 for 3 μm thickness at 293 K, respectively. Molecular dynamics simulation and density functional theory calculation further illustrate the root cause of different transfer rates and high selectivity due to the different Coulomb effects between various cations and channel walls. These results provide insight into the ion transfer behavior and separation mechanism in a charged confinement regime.

中文翻译：

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带亚纳米通道的带电层状双氢氧化物可有效进行单价阳离子筛分


用于精确分离的单价阳离子选择性膜的设计需要全面了解传输通道的几何形状和化学环境。这里，通过层状双氢氧化物的逐层自组装构建了亚1纳米的带电阳离子传输通道。为了有效提高分离性能，对膜的厚度和分离性能测试温度进行了探索。增强的尺寸限制效应和壁库仑相互作用导致 K+/Na+ 比 Li+ 更好的迁移，这使得 K+/Li+ 或 Na+/Li+ 在 293 K 下对于 3 μm 厚度的选择性分别为 5.7 和 4.0。分子动力学模拟和密度泛函理论计算进一步说明了由于各种阳离子与通道壁之间的库仑效应不同而导致不同传输速率和高选择性的根本原因。这些结果提供了对带电限制区域中离子转移行为和分离机制的深入了解。