Fig. 2: Operando KPFM measurements on LLZO far from electrode.

a The factor k calculated at different points on Li|LLZO|Li surfaces at 300 mV potential difference between the two electrodes. The error bars corresponds to three independent experiments. b Schematic diagram of the position of the KPFM measurement on the LLZO surface. c, d Topography and CPD maps (6 µm × 5 µm) of the regions within the dotted box in b in an OCV state. e, f Averaged line profiles of the topography and CPD extracted from areas CP1 and CP2 in the direction of the arrow under different potentials applied to the WE, respectively.