Probing the Mechanical Properties of a Doped Li7La3Zr2O12 Garnet Thin Electrolyte for Solid-State Batteries.

Using the nanoindentation technique, we probed the mechanical properties of tape cast and sintered thin doped Li7La3Zr2O12 garnet electrolytes. For comparison, a bulk garnet sample fabricated by die pressing and sintering was also studied. The results indicate that the thin sample has a significantly higher elastic modulus (∼155 GPa), hardness (∼11 GPa), and indentation fracture toughness (∼1.12 ± 0.12 MPa·m1/2) than the bulk sample (∼142 GPa, ∼10 GPa, and ∼0.97 ± 0.10 MPa·m1/2, respectively). The above results demonstrate that the thin sample can more effectively prevent lithium dendrite penetration due to its better mechanical properties. Deformation and creep behavior analysis further indicates that the thin sample (1) has a higher resistance to withhold the charge/discharge stress and consequently deformation and (2) a lower creep exponent and likely high resistance to brittle failure.