Cellulose supramolecular ionogel with robust mechanical strength and thermal stability for flexible electronics

Abstract Ionogels hold great promise in the fields of flexible electronics and energy devices. However, a persistent challenge lies in the inherent trade‐offs among mechanical strength, ionic conductivity, and thermal stability. Here, we report a double‐network cellulose‐polyvinyl alcohol (Cel/PVA) ionogel via a facile [Emim]BF 4 displacement regeneration process. The ionogel with a densified supramolecular structure showed a tensile strength of 7.20 MPa, an ionic conductivity of 18.71 mS⋅cm −1 , a wide electrochemical window of 3.50 V, and outstanding thermal stability up to 135°C. Moreover, flexible sensors fabricated from this ionogel can detect various stimuli, including pressure, temperature, touch, and human pulse signals, producing detectable electrical signal outputs. In addition, the ionogel demonstrates reversible charge‐discharge behavior when tested as an electrolyte in a supercapacitor configuration. This work provides an effective structural design strategy for synergistically optimizing the comprehensive performance of cellulose ionogels, paving the way for their use in next‐generation flexible electronic devices.