An understanding of solid–liquid interfaces is of great importance for fundamental research as well as industrial applications. However, it has been very challenging to directly image solid–liquid interfaces with high resolution, thus their structure and properties are often unknown. Here, we report a quasi-liquid phase between metal (In, Sn) nanoparticle surfaces and an aqueous solution observed using liquid cell transmission electron microscopy. Our real-time high-resolution imaging reveals a thin layer of liquid-like materials at the interfaces with the frequent appearance of small In nanoclusters. Such a quasi-liquid phase serves as an intermediate for the mass transport from the metal nanoparticle to the liquid. Density functional theory-molecular dynamics simulations demonstrate that the positive charges of In ions greatly contribute to the stabilization of the quasi-liquid phase on the metal surface.

对固液界面的理解对于基础研究和工业应用都非常重要。然而，以高分辨率直接成像固-液界面一直非常具有挑战性，因此它们的结构和性质通常是未知的。在这里，我们报告了金属（In，Sn）纳米颗粒表面和使用液体细胞透射电子显微镜观察到的水溶液之间的准液相。我们的实时高分辨率成像在界面处显示了一层薄薄的液体状材料，并经常出现小的 In 纳米团簇。这种准液相用作从金属纳米颗粒到液体的质量传输的中间体。