Solid-liquid interfaces are central elements in (photo-)electro-catalytic energy conversion concepts and electrochemical energy storage systems underlying, for instance, low-temperature electrolyzers, fuel cells and conventional Li-ion batteries. The complex intercorrelations of interfacial liquid structure and elementary processes like catalytic electron or ion transfer reactions pose a particular challenge for understanding and controlling these electrified interfaces on an atomic scale.
At present, this delays rational advances over prominent limitations such as poor selectivities in the generation of chemical fuels, the reliance on rare or toxic catalyst/battery materials for instance in proton-exchange membrane (PEM) fuel cells, and chemical instabilities leading to the formation of a self-passivating SEI of uncontrolled morphology in Li-ion batteries. The lack of insight limits our ability not only to discover new combinations of electrode materials and liquid electrolytes, but also to take advantage of the exciting possibilities in exploring and utilizing the enzyme-resembling properties of 3D nanostructures that become increasingly accessible by top-down and bottom-up morphological shaping of the interface.
Only a dramatically improved molecular-level understanding of the specific solvent/ion/reactant/solid interactions and long-range dielectric screening, i.e. of the nature and dynamics of the electrochemical double layer, will lead to the required transformational progress. This progress is expected, e.g., to enable insight-based development of new electrolyte properties, tailoring the nature of the solid surface by doping, as well as its structure by sculpting or generation of local nano-confinements, all aiming to design an optimum interface for the targeted processes and functionalities.