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

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]BF₄ 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.