Highly Stretchable PU Ionogels with Self-Healing Capability for a Flexible Thermoelectric Generator
Junhuai Xu, Hui Wang, Hui Wang, Xiaosheng Du, Xu Cheng, Zongliang Du, Haibo Wang, Haibo Wang
Abstract
With the development of thermoelectric (TE) generator, the flexible, stretchable, self-healable, and wearable TE devices have aroused great interest. Therefore, we designed a self-healable and stretchable polyurethane (PU) ionogel, composed of polyurethane main chains with double bonds in the side, cross-linkers (BDB) and nonconjugated ionic liquids (EMIM:DCA). The PU ionogels with 30 wt % ILs have a high mechanical stretchability (300%), good tensile strength (1.61 MPa), and suitable Young’s modulus (0.79 MPa). The proposed materials also exhibited an excellent ionic figure of merit (ZTi) of 0.99 ± 0.3, as well as rapid self-healability in the absence of any external stimuli. The thermoelectric capability of PU ionogels kept stable under the severe condition (50% strain) and during self-healing process, which is rarely reported in recent studies. Furthermore, a stretchable and self-healable ionic thermoelectric capacitor device is also fabricated by the PU ionogels, which can efficiently convert heat into electricity.