Unified quantum theory of electrochemical kinetics by coupled ion-electron transfer

Abstract:  

The Butler-Volmer (BV) equation has become the standard model for electrochemical reaction kinetics, and yet a century later, it still lacks a clear microscopic basis. Butler (1936) first derived the BV equation from Gurney’s seminal “quantum theory of electrolysis” (1931), which assumed electron transfer (ET) or “neutralization” is a fast step coupled to proton transfer. Marcus (1956) famously challenged this picture with his theory of non-adiabatic ET coupled to solvent reorganization, but Marcus theory has hardly been applied in electrochemical engineering. Here, we present a unified quantum theory of coupled ion-electron transfer (CIET), which leads to a simple rate formula that smoothly interpolates between Marcus-like and BV-like kinetics for rate-limiting electron- or ion-transfer, respectively, with only a few adjustable parameters (reorganization energy, ion transfer free energies, and electronic coupling), that can be predicted from constrained ab initio simulations. A variety of examples in batteries, electrodeposition, and electrocatalysis suggest that CIET theory provides the missing link between quantum chemistry and electrochemical engineering.

Bio:

Martin Z. Bazant is the Chevron Professor of Chemical Engineering and Mathematics at the Massachusetts Institute of Technology and a member of the National Academy of Engineering. After a Ph.D. in Physics at Harvard (1997), he joined the MIT faculty in Mathematics (1998) and then Chemical Engineering (2008), where he served as Executive Officer of the Department from 2016 to 2020. His awards include the Alexander Kuznetsov Prize in Theoretical Electrochemistry (ISE), the Andreas Acrivos Award in Chemical Engineering (AIChE), and the MITx Prize for Teaching in MOOCs. He is a fellow of the International Society of Electrochemistry, the Electrochemical Society, the Royal Society of Chemistry, and the American Physical Society. He serves as President of the International Electrokinetics Society, Director of the D3BATT Center for Data-Driven Design of Batteries (Toyota Research Institute), Director of the Center for Battery Sustainability (MIT-Northeastern), and Chief Scientific Advisor for Saint-Gobain Research North America. He is also the Chief Scientist and Co-founder of Lithios, Inc. commercializing Advanced Lithium Extraction (ALE) from brines.