Nondestructively Visualizing and Understanding "Soft Short" and Li Creeping in All-solid-state Lithium-Metal Batteries

All-solid-state Li-metal batteries (ASLMBs) have the potential to outperform conventional Li-ion batteries in terms of high energy density and safety; however, their applications are challenged by the dendrite-related short circuit. Therefore, it is imperative to understand the mechano-electro-chemo behavior of Li. For the first time, we nondestructively visualize the Li behavior in ASLMBs through operando neutron imaging and X-ray computed tomography (XCT). The 2D neutron radiography tracks the real-time Li evolutions before and after the "soft short". The 3D neutron tomography evidences the Li-metal deformation, and XCT provides 3D views of the battery after the "soft short". Despite "soft short", our observation indicates that Faradaic processes persist. Meanwhile, the coupling of stacking pressure and plating-induced stress triggers the Li-metal deformation toward the current collector and the SE, which results in the "soft short". This work inspires future research on stabilizing the Li metal in ASLMBs from the mechano-electro-chemo aspect.