Fig. 7

SEM images of the polymer and a schematic showing dendrite growth. SEM images. a After 3 days of cycling (scale bar representing 50 µm), b after 7 days of cycling (scale bar representing 100 µm), c after 9 days of cycling (scale bar representing 50 µm), and d after 13 days of cycling (scale bar representing 50 µm). e High magnification of the red box in image c (scale bar representing 20 µm), and f high magnification of the red box in image d showing the morphological change on the SPE (scale bar representing 20 µm). The cycling points at which these images were obtained are indicated in Supplementary Fig. 4 by blue arrows. g Schematic of the dendrite formation and the effect of SPE melting on further dendrite growth. Images correspond to Supplementary Movie 2 and Supplementary Fig. 4