Compliant Yet Brittle Mechanical Behavior of Li2S–P2S5 Lithium‐Ion‐Conducting Solid Electrolyte

Young's modulus, hardness, and fracture toughness are measured by instrumented nanoindentation for an amorphous Li2S–P2S5 Li-ion solid electrolyte. Although low elastic modulus suggests accommodation of significant chemomechanical strain, low fracture toughness can facilitate brittle crack formation in such materials.