Self-gelated flexible lignin-based ionohydrogels for efficient self-powered strain sensors

Bio-based ionohydrogels (IHs) have attracted significant attention in flexible electronics. However, their reliance on external power sources has limited their application in sensors, posing challenges for achieving self-powered systems with portability and stability. In this work, we developed self-gelated lignin-based IHs (L-IHs) via a radical polymerization process initiated by aminated lignin in an alkaline catalytic environment. The resulting L-IHs exhibit excellent compressibility and high conductivity (2.501 mS cm(-1)), enabled by physical and chemical interactions within the intrinsic 3D cross-linked network. Strain sensors fabricated with L-IHs demonstrate high strain sensitivity (GF = 1.14), long-term durability, and effective human-machine interaction. Additionally, we designed a self-powered flexible sensor utilizing the redox reaction in galvanic cells, with L-IHs serving as the electrolyte. This sensor delivers stable voltage output (similar to 1.48 V), a broad sensing range (5-60 kPa), high sensitivity, and superior system reliability, offering a promising approach for practical applications in self-powered sensors.