A Superstrong and Ultratough Stretchable Electronic Conductor With Ultradurable Strain-Insensitive Electromechanical Performance.

Developing high-performance stretchable electronic conductors (SECs) is vital for advancing soft electronics and robotics. However, existing SECs still suffer from limited mechanical robustness and vulnerable conductive pathways, undermining their electromechanical stability and durability in stretchable electronic applications. Here, we report a superstrong and ultratough SEC that exhibits ultradurable strain-insensitive electromechanical performance, deliberately engineered by dispersing a viscoplastic quasi-solid conductive filler into a superstrong, ultratough supramolecular elastomer. Instead of utilizing liquid metal (LM) as the conductive filler, we developed an LM-Ag alloy that becomes a viscoplastic quasi-solid conductor yet exhibits thixotropic flow, while also demonstrating lowered surface tension and enhanced interfacial interaction with the supramolecular elastomer. Our design effectively prevents LM leakage, addressing the formidable challenge encountered in conventional LM-based SECs. Importantly, the LM-Ag alloy enables thixotropic flow to establish additional conductive pathways upon stretching, endowing the SEC with strain-insensitive conductance. The SEC displays superhigh strength (∼20.0 MPa) and ultrahigh toughness (∼66 MJ m-3), showing negligible resistance change (R/R0 ≈ 1.07) at 300% strain and <3% resistance increase even after 20 000 stretching-releasing cycles. Consequently, the SEC affords high-fidelity electrical signal transmission under stretching, enabling the construction of wearable physiological monitoring and human-machine interaction systems that maintain functional stability during body movements.