First-principles electrochemistry with grand-canonical DFT and continuum-solvation methods*

First-principles calculations combining density-functional theory (DFT) and continuum solvation models have been highly successful in enabling the theoretical design of liquid-phase catalyst materials. The application of such methods to heterogeneous catalysis in electrochemical solid-liquid interfaces has however been far more challenging for two reasons. First, conventional continuum solvation methods designed for finite molecular systems are not readily applicable to solid-liquid interfaces with metal or oxide surfaces. Second, processes at these interfaces continuously exchange electrons with the electrode, which makes the charge states of the surface difficult to determine.

I will present recent developments in continuum solvation methods that enable simultaneously accurate treatment of solid surfaces and molecules in electrochemical interfaces. Additionally, by automatically equilibrating charge at a fixed electrochemical potential, new 'grand-canonical DFT' algorithms and software (JDFTx) facilitate realistic description of processes in these interfaces. Together, these methods enable first-principles prediction of electro- and photo-catalysis mechanisms for energy conversion, and of the surface structures and dynamics in battery materials. With clean prototypical electrochemical measurements as a benchmark, I will outline the present capabilities, pending challenges and necessary future developments in first-principles electrochemistry in a wide range of electrochemical environments.