A Phase Field Model of Electrodeposition with the Effect of Double Layer

Abstract

The growth of dendrites is a central problem in advanced rechargeable lithium-ion batteries. The phase field method has been used to simulate electrodeposition due to its flexibility in handling complex microstructural morphologies such as dendrites. Generally, two types of phase field models are available. The first type employs a detailed description of the double layer that, unfortunately, is very computationally challenging and hinders its application to studies beyond one dimension. The second type neglects the effect of double layer at the Li-electrolyte interface to simulate systems of practical size in more than one dimension. In this work, we propose a phase field model the does not account for detailed double layer structure but includes the effect of the double layer in the free energy, achieving a balance between computational efficiency and accuracy. The model also accounts for the highly anisotropic interfacial energy of the Li-electrolyte interface, thus allowing the dendrites to have sharp corners. The role of the double layer and highly anisotropic interfacial energy on Li metal dendrite growth will be discussed.