Mathematical Modeling of Electrochemical Systems at Multiple Scales in Honor of Professor John Newman

Advancing our understanding of electrochemical phenomena, and ultimately improving the operation and design of electrochemical systems, is aided by the use of advanced simulation tools that enable researchers to de-convolute complex, interacting phenomena. The challenge in developing these tools is that length scales in electrochemical applications can range from electronic to atomic to molecular to nanoscale to microscale to macroscale. Figure 1 illustrates some of the computational methods that have been developed to deal with phenomena at these disparate time and length scales to compute properties and model phenomena.1 This focus issue of the Journal of the Electrochemical Society is devoted to the mathematical modeling of electrochemical systems across multiple scales. It is dedicated to the work of Professor John Newman from UC Berkeley, who helped establish the field of modeling of electrochemical systems, and is aligned with a previous focus issue2 and regular symposium on multiscale modeling for electrochemical systems at ECS biannual meetings. He dedicated his career to this topic, and he trained and influenced countless researchers over the years to analyze, simulate and optimize electrochemical systems using quantitative, and detailed mathematical models for different phenomena.3 His impact cuts across different electrochemical systems as witnessed by papers in different areas in this focus issue, lithium-ion batteries, fuel cells, corrosion, flow batteries, molten salts, etc. The papers published in this focus issue include model based experimental design, analysis and control, model based analysis of anomalies in experimental observation, and also a great discussion on the gap between model prediction and experimental observation. To honor the breadth of his accomplishments, papers here deal with fracture modeling and volume-change predictions in lithium-silicon batteries, the growth behavior of nanoparticles, synthesis of ammonia in molten salts, ab-initio molecular dynamic simulations of the solid-electrolyte interface, and predictions of band-to-band tunneling of electrons through the energy bandgap, to name just a few. We hope these papers and Professor Newman's influence continue to inspire readers to add mathematical modeling to their toolbox to accelerate the development of electrochemical systems and technologies.