Visualizing plating-induced cracking in lithium-anode solid-electrolyte cells

Abstract

Lithium dendrite (filament) propagation through ceramic electrolytes, leading to short-circuits at high rates of charge, is one of the greatest barriers to realising high energy density all-solidstate lithium anode batteries. Utilising in-situ X-ray computed tomography coupled with spatially mapped X-ray diffraction, the propagation of cracks and the propagation of lithium dendrites through the solid electrolyte have been tracked in a Li/Li6PS5Cl/Li cell as a function of the charge passed. On plating, cracking initiates with spallation, conical "pothole"-like cracks that form in the ceramic electrolyte near the surface with the plated electrode. The spallations form predominantly at the lithium electrode edges where local fields are high. Transverse cracks then propagate from the spallations across the electrolyte from the plated to the stripped electrode. Lithium ingress drives the propagation of the spallation and transverse cracks by widening the crack from the rear, i.e. the crack front propagates ahead of the Li. As a result, cracks traverse the entire electrolyte before the Li arrives at the other electrode and therefore before a short-circuit occurs.

Review on Interface and Interphase Issues in Sulfide Solid-State Electrolytes for All-Solid-State Li-Metal Batteries

“…Such a reduction-expansion-cracking reaction is repeated and thus makes large cracks and form Li clusters inside the Li3PS4 electrolyte, finally causing a short circuit (Figure 7c,d). A very recent study by Ning et al using in situ X-ray CT in Li/Li6PS5Cl/Li system also demonstrated that the cracking is initiated near the surface with the plated electrode, and that the cracks propagate across the electrolyte from the plated to the stripped electrode [84], which agrees well with previous observations [83]. Similarly, Kazyak et al observed Li dendrite penetration through Li3PS4 electrolyte using operando optical microscopy [54].…”

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

“…3(112) GB], and the existence of the Schottky-like defects further decrease the Ef of Li i × thereby enhancing the enrichment of Li in the GB regions, which is expected to result in the preferential deposition at GB during charging, which may be correlated to the recently reported crack formation in the LLZO. 51,52 Furthermore, the excess electrons show a strong preference to be localized in the GB regions.…”

In Situ Formed Ag‐Li Intermetallic Layer for Stable Cycling of All‐Solid‐State Lithium Batteries

“…Although Li filaments were not detected due to resolution limitations, the Li cell showed a non‐uniform SE/Li interface as shown in Figure 3c , displaying protruded Li inside the SE owing to uneven Li plating or crack generation that provides additional room for Li storage during cycling. [ 12 , 13 , 14 , 15 , 16 ] In contrast, the Ag‐Li cell exhibited a uniform SE/Ag‐Li interface even after 30 cycles. These features were more conspicuous in the top‐viewed XRM image obtained along the vertical direction (Figure 3a,d ).…”

“…[ 7 , 9 , 10 , 11 , 12 ] Moreover, some studies have reported that, once a crack is generated by stress due to the inevitable volume change of the cell during cycling, and propagated inside the SEs by the Li filament growth, a short‐circuit would occur. [ 12 , 13 , 14 , 15 , 16 ] Therefore, to circumvent this chronic issue, various approaches for introducing Li host and defect‐free densely packed SEs, and generating protective layers including artificial solid state interphase have been attempted. [ 4 , 5 , 6 , 17 , 18 ] Nevertheless, these approaches have limitations in reducing dead volume in the 3D host, forming dense SE layers without any physical defects, and making the fabrication process easier.…”