Quantitative Phase Field Modeling of Dendrite Growth of Lithium Metal Anode

Dendrite growth is one of the main challenges to the success of using lithium metal anodes in solid-state batteries. The ability to simulate detailed dendrite growth in 3D under experimental conditions will benefit the community by providing a fundamental understanding of the growth mechanism and interfacial stability. This opens new possibilities to explore and design application-dependent battery materials and structures to suppress dendrite growth. Here, we developed a quantitative phase field model based on nonequilibrium thermodynamics in a fully variational and thermodynamically consistent way. The proposed model reproduces the Nernst equation, captures reaction kinetics like Butler-Volmer and Marcus-Hush, and can also include elastic stress. We verify our model against analytical solutions from sharp interface models with simple geometries to demonstrate that our model can give quantitative predictions. The proposed model enables the simulation of systems of experimental size with realistic materials parameters in three dimensions. We show simulations of dendrite growth as a function of applied voltage/current, demonstrating the effects of nucleation density and the mossy-to-dendritic lithium transition. The model can be easily extended to model other alkali metal anodes.