Rapid electrification is essential for climate change mitigation, but its large-scale deployment depends on addressing the urgent challenges posed by critical raw materials, including supply constraints and geopolitical vulnerabilities. Zinc-based batteries are promising candidates for stationary energy storage, offering a potentially safer and more sustainable alternative based on more abundant elements. Understanding their potential requires a deeper knowledge of the fundamental processes that govern electrode–electrolyte interfaces.

In this lecture, I will explore the fundamental surface and interfacial processes that occur during zinc electrodeposition, including hydrogen evolution, corrosion, passivation, and the formation and evolution of interphases. These competing reactions can strongly influence how zinc deposits, how charge is consumed, and how the electrode evolves during cycling.

Scanning electrochemical microscopy (SECM) provides a unique way to spatially resolve and monitor these processes in real time, allowing local electrochemical activity at the zinc–electrolyte interface to be directly linked to changes in electrode behaviour. By combining SECM with complementary electrochemical and spectroscopic approaches, we can identify the processes responsible for irreversible reactions and their impact on battery performance. 

Across a range of battery-relevant electrolytes, we find that hydrogen evolution decreases during cycling as the zinc surface and its interfacial chemistry evolve. Importantly, SECM measurements show that, under these conditions, hydrogen evolution accounts for only a small fraction of the irreversible capacity loss.Our results demonstrate how operando electrochemical measurements can disentangle competing reactions at dynamic interfaces, providing fundamental insights into zinc electrodeposition and guiding the development of more sustainable energy storage systems based on abundant materials.