Fig. 1: Schematic design of the untethered triboelectric electronic skin (UTE-skin).

a Schematic illustration of the fabrication process for the stretchable UTE-Skin. b The exploded view of the UTE-skin architecture involving elastic circuits, elastic electrodes, elastic triboelectric layer, and elastic shielding layer. c The broad applications of the UTE-skin in robotic skins, stretchable keyboards, smart insole, and smart gloves. d Scanning electron microscope (SEM) image of carbon blacks. Scale bar: 100 nm. e Top-view and (f) cross-section SEM images of the conductive composite of carbon blacks and Ecoflex. Scale bar: 100 nm. Five independent experiments of (d–f) were performed with similar results. g Photographs of an as-fabricated triboelectric sensor array-based e-skin (left image) under folding, crumpling, twisting, and stretching, demonstrating its mechanical robustness.