Zwitterionic Polymer Gel-Based Fully Self-Healable Ionic Thermoelectric Generators with Pressure-Activated Electrodes

Heat generated from various sources is inevitably wasted. Thermoelectric generators (TEGs) are suitable for recovering such waste heat because of their simple structure and operating principle. Herein, a zwitterionic (ZI) polymer-based fully self-healable ionic TEG is presented. By adjusting the position of the positive and negative moieties of the ZI side chain, the movement of free ions contained in the ionogel can be controlled effectively, thus improving the power factor of TEGs. ZI side chains inside the ionogel provide multiple ionic interaction sites and enable fast self-healing characteristics at room temperature. Furthermore, a self-healing electrode composed of liquid metal (LM), waterborne polyurethane (WPU), and polyvinyl alcohol (PVA) is developed for the fully healable TEGs. The overall areal output voltage is effectively improved by connecting 10 legs of p and n thermoelectric gels in series via a self-healing process. The selectively ion-boosted, fully self-healable TEGs developed in this study will open a new horizon for high-performance ionic TEGs.