Organic/Inorganic Hybrid Ionogel Fiber with Synergistically Enhanced Mechanical and Ionic Thermoelectric Performances

Fiber-based thermoelectric (TE) device that can collect waste heat of human body and convert it into electricity is growing fast and is of great significance for sustainable development. Although ionic thermoelectric (i-TE) ionogels are considered to be the next generation of TE materials, to construct ionogel fiber with synergistically enhanced mechanical and i-TE performances remains big challenge. Herein, the poly(vinylidene fluoride-co-hexafluoropropylene)/1-ethyl-3-methylimidazolium dicyanamide/ethanol/NaTFSI/SiO₂ (PH/ED-E-Na-SiO₂) ionogel with ultrahigh ionic Seebeck coefficient of 47.5 mV K⁻¹ and ionic conductivity of 43.7 mS cm⁻¹ is constructed by a proposed antisolvent-doping-hybrid synergistic strategy. The enhanced i-TE performances are mainly attributed to the low crystalline structure and the improvement in ions dissociation, migration, and diffusion difference. The corresponding power factor of the PH/ED-E-Na-SiO2 ionogel film is as high as 9845.8 μWm⁻¹ K⁻², which is almost the highest value ever reported. Based on this, the ionogel fiber with comparable i-TE performances and significantly enhanced tensile strength and strain (from 327 Kpa and 47% of film to 17.7 MPa and 70% of fiber) is prepared by a simple coating process. It can be weaved into wearable i-TE device that generates high thermovoltage and lights the light-emitting diode (LED) bulb, demonstrating its great application potential as wearable energy supply device.