To corroborate this experimentally, we qualitatively infer surface electronic conductivity from the lithium plating diameter via operando microprobe SEM. Specifically, we compared the lithium plating diameter at failure between uncoated LLZO, Ag + -LLZO and Ag 0 |LLZO (Figure ). Multiple independent tests (n = 29 for uncoated LLZO, n = 13 for Ag + -LLZO, n = 15 for Ag 0 |LLZO) were performed a low indentation stress arising from the microprobe (<100 MPa) to minimize the impact of external stress on surface conductivity. If the Ag + -LLZO samples exhibited an increase in surface electronic conductivity, we would expect that the aspect ratio of Li electroplating would be larger than uncoated LLZO due to facile lateral charge transport. The lateral diameter was measured based on the SEM images while the height of the plated Li was estimated by dividing the total plated Li volume (converted from total lithium plating capacity) by the plating area. Experimentally, the aspect ratio of electroplated Li at different failure capacities reveals no substantial differences between uncoated and Ag + -LLZO surfaces (Figure ). This indicates that Ag + doping has no substantial impact on the surface electronic conductivity. In contrast (and as be expected), Ag 0 |LLZO exhibits a significantly larger aspect ratio, suggesting predominantly lateral Li growth during electroplating. This is expected due to the high conductivity of metallic Ag before it has incorporated as a dopant during annealing. The similarity in the aspect ratio of plated Li between uncoated and Ag + -LLZO also suggests that the surface doping does not substantially modify Li wetting, unlike in the case of metallic Ag coating.