THE EFFECT OF IMPORTANT FACTORS ON THE GROWTH OF LITHIUM DENDRITES IN SOLID ELECTROLYTE WAS SIMULATED BASED ON PHASE FIELD THEORY

The growth of lithium dendrites is one of the important challenges for the safety of solid-state batteries. In order to further investigate the formation mechanism of lithium dendrites, a phase field model of electrochemic-mechanical coupling was established to simulate the influence of important factors on the growth of lithium dendrites in solid electrolyte. In this study, the dynamic distribution of lithium ion concentration field, electric potential field and stress field was simulated, and the influence of anisotropy intensity, reaction constant, external pressure, ambient temperature and initial nucleation shape on the growth morphology of dendrites was revealed, and the morphological characteristics of needle and moss dendrites were compared. The results show that reducing the anisotropy intensity and reaction constant can inhibit the growth of lithium dendrites to a certain extent. The growth of lithium dendrites can be effectively inhibited by increasing external pressure and ambient temperature. The initial nucleation shape of lithium by increasing external pressure and ambient temperature. The initial nucleation shape of lithium dendrites can significantly affect their branching direction. The comparison of the three forms of lithium dendrites shows that the acicular dendrites have fewer branches, and the stress is mainly concentrated in the dendrite root. Mossy dendrites have larger branch structure due to their higher spatial freedom of growth and higher internal stress level during growth. Dendritic dendrites are intermediate between acicular dendrites and moss dendrites, with uniform distribution of branches and stresses. This study is of great significance for optimizing the design of solid-state batteries and improving their safety.