Interfacial deposition stability between lithium metal and a solid electrolyte (SE) is important in preventing interfacial contact loss, mechanical fracture, and dendrite growth in Li-metal solid-state batteries (SSBs). In this work, we investigate the deposition and mechanical stability at the Li-metal/SE interface and its consequences (such as SE fracture and contact loss). A wide range of contributing factors are investigated, such as charge and mass transfer kinetics, plasticity of Li-metal and fracture of the SE, and the applied stack pressure. We quantify the effect of the ionic conductivity of the SE, the exchange current density of the interfacial charge-transfer reaction, and SE surface roughness on the Li deposition stability at the Li-metal/SE interface. We also propose a “mechanical stability window” for the applied stack pressure that can prevent both contact loss and SE fracture, which can be extended to other metal-electrode (e.g., sodium) SSB systems.

锂金属与固体电解质（SE）之间的界面沉积稳定性对于防止锂金属固态电池（SSB）中的界面接触损耗，机械断裂和枝晶生长很重要。在这项工作中，我们研究了Li-metal / SE界面处的沉积和机械稳定性及其后果（例如SE断裂和接触损耗）。研究了广泛的影响因素，例如电荷和传质动力学，锂金属的可塑性和SE的断裂以及所施加的堆压。我们量化了SE的离子电导率，界面电荷转移反应的交换电流密度以及SE表面粗糙度对Li-金属/ SE界面处Li沉积稳定性的影响。