PF-MD Coupled Model and Suppression Strategies for Lithium Dendrite Growth in Solid-State Batteries

Abstract

The transition from liquid organic electrolytes to solid-state electrolytes offers a promising pathway toward high-energy-density lithium-metal batteries with enhanced safety profiles. However, the practical implementation of solid-state batteries is severely hindered by the pervasive issue of lithium dendrite growth, which leads to short circuits and mechanical degradation of the electrolyte. Traditional modeling approaches, relying solely on continuum mechanics or atomistic simulations, fail to capture the multiscale nature of dendrite propagation, which involves atomic-level interface kinetics and mesoscale morphological evolution. This paper presents a comprehensive multiscale framework coupling Molecular Dynamics simulations with Phase-Field modeling to investigate the mechanisms of lithium dendrite growth and evaluate effective suppression strategies. The Molecular Dynamics component determines the temperature-dependent transport properties and interfacial energies, which are subsequently integrated into the Phase-Field model to simulate microstructural evolution under varying electrochemical and mechanical conditions. Our results elucidate the critical role of grain boundary inhomogeneity and interfacial stress accumulation in promoting dendritic structures. Furthermore, we propose and validate suppression strategies, including the optimization of external stack pressure and the engineering of high-modulus artificial interlayers. The coupled model demonstrates that tailoring the mechanical properties of the solid electrolyte interphase can significantly retard dendrite velocity, providing theoretical guidance for the rational design of next-generation solid-state batteries.