An Investigation of Chemo‐Mechanical Phenomena and Li Metal Penetration in All‐Solid‐State Lithium Metal Batteries Using In Situ Optical Curvature Measurements

Abstract

Solid‐electrolytes (SEs) can provide a pathway to increase energy‐density in lithium metal batteries. However, lithium metal penetration through garnet based LLZO solid electrolytes has been identified as a critical failure process. This phenomenon is related to chemo‐mechanical processes which are difficult to probe. In particular, characterizing the dynamic mechanical deformations that occur in electrode‐SE structures is very challenging. This study reports in situ curvature measurements that are thus designed to probe chemo‐mechanical phenomena that occur during lithium plating. The novel experimental cell configuration created for this work shows that pressure builds up in the Li metal during plating, up until the point where short circuits occur. The resulting data are analyzed with a detailed finite element model (FEM) to quantitatively evaluate stress evolution. The results show that Li metal plating within a surface flaw can produce stress build‐up prior to short‐circuiting. The combined results from both the experiments and the FEM suggest that it is critical to minimize surface defects and flaws during the manufacturing processes.

Recent advances in in situ and operando characterization techniques for Li7La3Zr2O12-based solid-state lithium batteries

“…28c and d) was designed to in situ monitor the displacement induced by mechanical stresses through the measurement of wafer curvature. 251 This technique is capable of investigating the chemo-mechanical evolution during electrochemical cycling. A thin Al 2 O 3 layer is plated between LLZO and melted Li utilizing atomic layer deposition to improve interface contact.…”

Tradeoff between the Ion Exchange-Induced Residual Stress and Ion Transport in Solid Electrolytes

“…In a high-density, well-polished LLZO sample, the grain size serves as a reasonable limiting value for a C . A wide range of grain sizes have been reported for sintered LLZO, for example, 2−5 μm by Cho et al 90 and 1−50 μm (depending on the dopant used) by Yu et al 52 In this work, we consider grain sizes from 1 to 20 μm. At 1200 K, the time (∼λ 2 /2D K ) for K + to diffuse through a thickness of 1 or 10 μm is on the order of 25 s or 0.7 h. Setting the ion exchange thickness to twice the grain size, λ = 2a C for an electrolyte thickness of 1 mm, this corresponds to an exchange depth ratio (λ/t) of 0.2−4%; thus, our shallow depth approximation still holds.…”

Integrating an In‐Plane Electron‐Conductive Separator to Enable Short‐Circuit Warning in Lithium–Sulfur Batteries

“…[28][29][30] Even in all-solid-state batteries, dendritic lithium is still able to penetrate the solid electrolytes. [31][32][33] In LIBs, the formation of lithium dendrites could be detected by the potential difference between the conventional anodes (e.g., graphite and silicon) and a lithium anode. [34,35] Nevertheless, similar predictions become elusive in Li-S batteries.…”