Understanding and Predicting the Lithium Dendrite Formation in Li-Ion Batteries: Phase Field Model

Lithium (Li) dendrite formation compromises the reliability of Li-metal batteries, either because dendrite pieces lose electrical contract or growing dendrite penetrates the separator and leads to internal short-circuiting. In this paper, a nonlinear phase-field model is formulated to predict Li dendrite formation at the electrode/electrolyte interface. The phase field evolves by electrochemical reaction of which the rate depends on nonlinearly the thermodynamics driving force involving overpotential and ion concentration. A revised Poisson-Nesters-Planck Equation is further solved for ionic transport and local overpotential variation. The model is validated by 1-D fields distribution involving phase field, Lithium ion concentration and electrostatic potential. The 2-D tree-type lithium dendrite during Li deposition was produced if anisotropic surface energy is assumed. Finally, the 2D morphological evolution under different electrochemical conditions specified by the charging current density, and the anisotropy of surface energy was discussed.