Dynamic Electrochemical Interfaces for Energy Conversion and Storage

Abstract

Electrochemical energy conversion and storage are central to developing future renewable energy systems. For efficient energy utilization, both the performance and stability of electrochemical systems should be optimized in terms of the electrochemical interface. To achieve this goal, it is imperative to understand how a tailored electrode structure and electrolyte speciation can modify the electrochemical interface structure to improve its properties. However, most approaches describe the electrochemical interface in a static or frozen state. Although a simple static model has long been adopted to describe the electrochemical interface, atomic and molecular level pictures of the interface structure should be represented more dynamically to understand the key interactions. From this perspective, we highlight the importance of understanding the dynamics within an electrochemical interface in the process of designing highly functional and robust energy conversion and storage systems. For this purpose, we explore three unique classes of dynamic electrochemical interfaces: self-healing, active-site-hosted, and redox-mediated interfaces. These three cases of dynamic electrochemical interfaces focusing on active site regeneration collectively suggest that our understanding of electrochemical systems should not be limited to static models but instead expanded toward dynamic ones with close interactions between the electrode surface, dissolved active sites, soluble species, and reactants in the electrolyte. Only when we begin to comprehend the fundamentals of these dynamics through operando analyses can electrochemical conversion and storage systems be advanced to their full potential.

Electrolyte-Induced Restructuring of Acid-Stable Oxygen Evolution Catalysts

“…In the context of the Lux acid−base classification, 61 the lattice oxide is a strong base and accordingly is prone to protonation and attendant structural reorganization. 62 Even in the presence of strong base, the condition under which many OER oxide catalysts operate, there is an advantage to surface reorganization to produce terminal oxo/hydroxo active sites. Within the crystalline environment, oxygen is bound to multiple metals, resulting in its kinetic inertness owing to the need to overcome multiple bond activations.…”

“…Such amorphization is expected as water splitting generates protons at the electrode–oxide interface. In the context of the Lux acid–base classification, the lattice oxide is a strong base and accordingly is prone to protonation and attendant structural reorganization . Even in the presence of strong base, the condition under which many OER oxide catalysts operate, there is an advantage to surface reorganization to produce terminal oxo/hydroxo active sites.…”

Operando X-ray characterization of interfacial charge transfer and structural rearrangements

“…The solid-liquid interface under reaction conditions undergoes transformations because of electrochemical processes like ion insertion or surface (redox) reactions such as adsorption, desorption, dissolution and phases changes. 11 These can precede electrocatalytic reactions of interest 12 or occur at almost the same potential. 13 Therefore, both the surface and the bulk of the solid at applied stimulus may have a different composition and structure compared to open-circuit conditions.…”

Exploring how cation entropy influences electric double layer formation and electrochemical reactivity

“…Electrochemical interfaces are a core area of research in the soft matter community [1][2][3] for advanced energy storage 4,5 and electrocatalytic systems 6,7 that provide opportunities to offset anthropogenic CO 2 emissions. [8][9][10] For example, converting CO 2 into useful chemical products through electrocatalysis offers a way to not only mitigate the effects of CO 2 emissions, but also to sustainably produce chemicals for industrial processes.…”