A mechanically robust and highly stretchable cross-linked dual-ionic conductive elastomer

•Crosslinked network improves the mechanical properties of the conductive elastomer.•Dual-ionic system improves the conductivity of the crosslinked elastomer.•The wearable sensors made of such elastomers can sensitively monitor body motions.•The novel elastomers exhibit extremely high transparency and stability. Generally, linear or dynamic crosslinking structures are selected to prepare ionic conductive elastomers. Although these elastomers have good conductivity, they usually come with poor mechanical properties due to the strong motion ability of flexible chain segments. The preparation of liquid-free ionic conductive elastomers in combination with robust mechanical properties and high conductivity is a consistently difficult and challenging work. Based on the cross-linked structure and dual-ionic conductive system, here, a series of novel cross-linked dual-ionic conductive elastomers (CDICEs) are synthesized. They show the excellent mechanical properties. The best tensile strength of CDICE reaches 16.4 MPa, and the best strain-at-break could reach 1410 %. The mechanically robust CDICEs also exhibit good conductivity (0.5 × 10−3–8.3 × 10−3 S m−1, 25 °C) and outstanding freeze/heat-resistant performance (−20 °C–140 °C). The cross-linked PEG network improves the mechanical properties, and the addition of lithium salt (LiTFSI) and choline chloride (ChCl) improve the conductivity. The wearable sensors made of such elastomers can sensitively monitor body motions like bending of finger, wrist or elbow. As a durable, reliable material, it exhibits great potential for applications in electronic skins and wearable devices.