Catalyst-Free Engineered Robust Cellulose Ionogel for High-Performance Ionotronic Devices

Ionogels, a newly emerging type of gel material, are considered the most attractive candidate for constructing the next-generation ionotronic devices in the Internet of Things era. However, building robust and sustainable ionogels toward high-performance ionotronic devices in broad scenarios remains a huge challenge. Herein, a mechanically robust cellulose ionogel (RCI) via the facile “catalyst-free” yet chemically cross-linked engineering of cellulose molecules was developed. More specifically, ionic liquid, a typical cellulose solvent, and an ion-conductive component of cellulose ionogel were employed to afford the proton and replace the conventional, additional chemical catalyst, which indeed triggers the chemical reactions between cellulose and glutaraldehyde molecules, and thus creates the chemical-bonded, robust cellulose network of RCI. The prepared RCI (0.4 g glutaraldehyde to 0.6 g cellulose) demonstrated surprisingly high strength of ∼11 MPa with 1 000% improvement and toughness of 2.8 MJ/m 3 with 700% increase compared to the original cellulose ionogel (CI), as well as acceptable conductivity of 29.1 ms/cm, surpassing most ionogel materials. Such RCI easily constructed versatile ionotronic devices with unexpected voltage-pressure sensitivity, wide-range loading, and linear and steady-state output for self-powered, body motion, human health, and Morse-code information communication applications. The catalyst-free engineering paves the way toward easy-to-prepare, robust, and promising ionogels in our sustainable society, beyond the cellulose material.