Surface and Interfacial Dynamics in Electrochemical Energy Materials

The functionality of an electrocatalytic material is primarily dependent on its surface and interfacial properties. This elevates the need to truly understand the nature of the surface sites, in particular during operation, as both structure and composition may change and evolve, creating active sites with unique electronic properties than its parent bulk phase, even though they may remain intimately connected. In this talk we will cover examples of changes to surface composition and structure that are dynamically in nature, with direct impact to a material ability to catalyze the O₂ evolution reaction in alkaline media. By employing the Stationary Probe Rotating Disk Electrode (SPRDE) coupled to and ICP-MS we can reveal the dynamic exchange of Fe ions from the interface of a 3d transition metal oxide, establishing a direct correlation between material durability to reaction stability. In turn it helps us understand the role of Fe as a dynamically stable active site and how to design metal oxide surfaces that can increase the average Fe coverage at the interface, which is critical for high OER activities. We then demonstrate the importance of measuring in real time the catalyst’s activity and dissolution rates in practical conditions such as 30 wt% KOH solutions. This helps us connect the design rules learned from fundamental studies to the challenges in their implementation in practical systems as additional constraints must be considered. Lastly, we will discuss a framework for mitigating the degradation of materials for clean energy systems, discussing technical and economic challenges and opportunities.