Abstract
Solid-state lithium-metal batteries (SSLBs) represent a promising frontier for high-energy-density energy storage, yet their practical deployment is severely hindered by lithium dendrite penetration through the solid electrolyte. In this study, we present an in-situ characterization of lithium dendrite evolution in a symmetric Li | Li6PS5Cl (LPSCl) | Li solid-state cell using high-resolution synchrotron X-ray computed micro-tomography. By cycling the cell at systematic current densities (0.5 to 2.0 mA cm-2) while simultaneously capturing 3D tomographic volumes at a spatial resolution of 0.8 µm, we map the real-time nucleation, propagation, and morphologic transition of lithium filaments. The results reveal that dendrite growth initiates at localized void spaces and grain boundaries near the lithium/electrolyte interface, propagating along microstructural defects under high local current density concentrations. Quantitative volumetric analysis demonstrates a critical current density (CCD) threshold of 1.2 mA cm-2, above which rapid interconnected dendritic networks form, leading to premature cell short-circuiting. This work provides deep spatial-temporal insights into the mechanical-electrochemical degradation pathways of solid-state electrolytes, offering critical design guidelines for engineering dendrite-resistant solid-state battery architectures.
