Highly stretchable, adhesive and 3D-printable eutectic ion conductor for wearable electronics and self-powered sensors

Abstract

The demand for flexible and wearable electronics requires materials that combine mechanical robustness, high conductivity, and multifunctionality. In this work, we present a novel eutectic ion conductor (EIC) based on eutectic solvents, designed to overcome the limitations of existing materials in flexible electronics. This material incorporates lithium salts as hydrogen bond acceptors (HBAs) to enhance both ionic conductivity (up to 76.3 mS m⁻¹) and mechanical strength (up to 7.68 MPa), while also providing robust adhesion (up to 129.6 kPa on glass) and excellent optical transparency (91%). The EIC's 3D printability allows for the creation of complex microstructures, enabling advanced fabrication techniques for wearable devices. We demonstrate the material's versatility through the development of a stretchable strain sensor and a self-powered triboelectric nanogenerator (TENG) with rapid response times (17 ms), high sensitivity, and stable performance. This work bridges the gap between material performance and scalability, offering a transformative platform for next-generation wearable sensors, energy-harvesting devices, and human–machine interfaces.