In-Situ Optical Tracking of Electrochemically Growing Metal Interface on Hydrogen Bubble Templated Electrodes

Controlling the growth morphology in electrochemical systems is critical for applications ranging from nanomanufacturing to energy storage devices. Conventional strategies to achieve a uniform deposition morphology (relevant in battery charging) typically rely on the modulation of applied input current, electrolyte additives as well as electrode designs. This work examines how electrode architecture influences the spatiotemporal evolution of metallic growth fronts. Electrodes were fabricated using the dynamic hydrogen bubble template (DHBT) method, which produced a variety of micron-scale textures ranging from pillars to valleys to bimodal porous walls by tuning the current input (constant and periodically fluctuating current densities). These complex features were viewed as combinations of peaks (structures) and recesses (interstructural gaps), characterized by their width, height, and number density. The substrates were subsequently used for electrodeposition in a two-electrode parallel cell, with optical monitoring of the respective transient metallic growth fronts. They were characterized in terms of deposition height, deposit front velocity, and surface undulation. The role of structure number density and the interstitial voids within the microstructures on the nature of the deposit were explored. The findings highlight the potential of base electrode engineering in controlling the growing interfacial topology, with a quantitative understanding of early stage (first few seconds) growth for application-specific control.