Robust and Highly Conductive Cellulose-Based Eutectogel for Flexible Electronics

High-performance ionic conductive gels are essential for the development of flexible electronic devices. However, the robustness and conductivity of gel materials are compromised at extreme temperatures. In this study, a high-performance eutectogel composed of cellulose and metal-based deep eutectic solvent (DES) was prepared. Specifically, cellulose was dissolved in a ternary DES (ZnCl₂/water/citric acid) at room temperature, and then another polymerizable DES (ZnCl₂/acrylic acid) was introduced to prepare eutectogels with multiple cross-linking hydrogen bonds. In such a design, the as-obtained eutectogels display a decent mechanical performance (tensile stress up to 1.43 MPa) and superior ionic conductivity (5.51 S m^–1). Furthermore, their excellent environmental adaptability allows their use across a wide range of temperatures from −45 to +95 °C. Eutectogel-based wearable multifunctional sensors are highly responsive to both tensile and compressive deformation, monitor human movement, and transmit stable and tunable electrical signals. As a solid-state eutectogel-based electrolyte, the assembled supercapacitor has a wide operating voltage window of 2.2 V and a high specific capacitance of 143.2 F g^–1 at a current density of 0.5 A g^–1. This work provides an idea for designing green and flexible gel-based electronic devices.