To quantify the electrochemical properties of Ag + -LLZO generated by annealing a 3-nm-thick metallic thin film between 100 and 400 ºC, we perform operando Li electroplating using an electrical microprobe platform inside FIB/SEM (Figure ). We further utilize the microprobe to indent the LLZO surface to mechanically generate defects, and carry out cryo-EM to image the indentation site while minimizing beam-induced damage. In the pristine, unindented LLZO, we observed no pre-existing nanoscale cracks up to a depth of 100 nm across a 10 µm wide FIB-prepared LLZO lamella (Figure ). To simulate mechanical damage, we apply a large local stress of 3 GPa by indenting a microprobe onto the LLZO surface. We observe nanoscale cracks < 2 nm in width at depths up to ~ 20 nm (Figure , sample preparation detailed in Figure and additional cryo-EM data shown in Figure ).