We study a variety of physical and chemical processes of materials with a focus on nanoscale materials transformations and dynamic phenomena at solid-liquid (including solid-liquid-gas) interfaces. We develop and apply in-situ liquid cell transmission electron microscopy (TEM) as our primary approach. We also use other tools and methods, including nanofabrication, X-ray spectroscopy, Cryo-EM and other electron microscopy techniques, and theoretical modeling. These efforts lead to depth understanding of nucleation, growth and materials transformations. It further enables the development of novel materials in various applications, such as, batteries, catalysis and materials corrosion protection.