Working with Martin Head-Gordon, we have created the first validated, accurate molecular model of the central steps that govern the rates of crucial dissolution/deposition reactions broadly relevant across energy and corrosion sciences. The team developed an experimental model system that to precisely measure and quantify the kinetics of fundamental ion-transfer processes that contribute to the degradation of catalysts and electrodes used in electrochemical energy systems. Concurrently, they constructed a quantum-mechanical computer model of the system to yield the energy profiles and provide physical insights into the effects of electric bias and field on the reaction barriers and the atomic-scale structures involved in the reaction. Together, the project elucidates how solvents and electrons influence the energy states and molecular structures involved in the creation of a charged ion on the surface of a metal during dissolution. This understanding provides crucial insights into corrosion processes that could impact infrastructure investments. Moreover, it leads to new perspectives on improving the durability of photochemical fuel generators, fuel cells to generate power, electrolyzers for hydrogen and carbon fuels production, and the electrochemical refining of metals. The team is expanding the approach to more-complex systems and to create a general molecular theory to describe the “birth and death” of ions at electrochemical interfaces.
https://pubs.rsc.org/en/content/articlelanding/2024/sc/d3sc05791g
Non-technical summary:
A project led by Shannon Boettcher, senior faculty scientist in Berkeley Lab’s Energy Storage & Distributed Resources Division, and Martin Head-Gordon, senior faculty scientist in Berkeley Lab’s Chemical Sciences Division, has created the first validated, accurate molecular model that describes the rates at which ions are created or consumed at the interface between a solid and a liquid. Ions are atoms or molecules that carry an excess or deficit of electrons and thus a charge. Ions – like those present in solution of salt water – are the species that carry electrical current in solutions. When a material rusts and dissolves, ions are created. When metals are plated from solution, for example to create semiconductor chips, ions are consumed. When an ion is in solution it is made more stable by forming chemical bonds to molecules making up the solution, for example water molecules. When the ion is created from a metal surface, these bond to the solvent are formed, but the sequence of molecular events and the resulting barriers that control how fast the ions can be formed (or consumed) was previously unknown prior to this new collaborative study that combined careful experiments with leading edge computation. The team is expanding the approach to complex systems create a general theory that is of importance broadly to electrochemical technology in renewable liquid fuel synthesis, batteries, and controlling corrosion processes.