In Situ Liquid Cell Electron Microscopy with Simultaneous Control of Heating, Biasing, and Flow

We report a liquid cell transmission electron microscopy (LCTEM) platform that enables simultaneous control of electrochemical bias, temperature, and liquid flow for in situ studies of nanoscale electrochemical processes. Using this system, we investigated copper (Cu) nucleation on platinum (Pt) electrodes under varying flow and temperature conditions. We find that electrolyte flow significantly modulates thermal effects: in static conditions, elevated temperatures promote longer Cu dendrites due to local ion depletion, whereas under flow, shorter dendrites form and depletion is suppressed. Flow control also enables rapid electrode cleaning and reproducible cycling between experiments. This integrated approach allows for precise control over reaction environments, revealing how nanoscale growth pathways are influenced by coupled thermal and mass transport phenomena. Our holder design expands the accessible parameter space for LCTEM, enabling mechanistic studies of electrochemical systems under conditions that better mimic real-world device environments such as batteries, fuel cells, and nanoscale electroplating reactors.