Lee Chia-Yu, Lin Yen-Ting, Hong Shao-Huan, Wang Chia-Hsin, Jeng U-Ser, Tung Shih-Huang, Liu Cheng-Liang
Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan.
Department of Chemical and Materials Engineering, National Central University, Taoyuan 32001, Taiwan.
ACS Appl Mater Interfaces. 2023 Dec 6;15(48):56072-56083. doi: 10.1021/acsami.3c09934. Epub 2023 Nov 20.
Mixed ionic-electronic conducting (MIEC) thermoelectric (TE) materials offer higher ionic conductivity and ionic Seebeck coefficient compared to those of purely ionic-conducting TE materials. These characteristics make them suitable for direct use in thermoelectric generators (TEGs) as the charge carriers can be effectively transported from one electrode to the other via the external circuit. In the present study, MIEC hydrogels are fabricated via the chemical cross-linking of polyacrylamide (PAAM) and polydopamine (PDA) to form a double network. In addition, electrically conducting carboxylated carbon nanotubes (CNT-COOH) are dispersed evenly within the hydrogel via sonication and interaction with the PDA. Moreover, the electrical properties of the hydrogel are further improved via the in situ polymerization of polyaniline (PANI). The presence of CNT-COOH facilitates the ionic conductivity and enhances the ionic Seebeck coefficient via ionic-electronic interactions between sodium ions and carboxyl groups on CNT-COOH, which can be observed in X-ray photoelectron spectroscopy results, thereby promoting the charge transport properties. As a result, the optimum device exhibits a remarkable ionic conductivity of 175.3 mS cm and a high ionic Seebeck coefficient of 18.6 mV K, giving an ionic power factor (PF) of 6.06 mW m K with a correspondingly impressive ionic figure of merit (ZT) of 2.65. These values represent significant achievements within the field of gel-state organic TE materials. Finally, a wearable module is fabricated by embedding the PAAM/PDA/CNT-COOH/PANI hydrogel into a poly(dimethylsiloxane) mold. This configuration yields a high power density of 171.4 mW m, thus highlighting the considerable potential for manufacturing TEGs for wearable devices capable of harnessing waste heat.
与纯离子导电的热电材料相比，混合离子 - 电子传导（MIEC）热电材料具有更高的离子电导率和离子塞贝克系数。这些特性使其适合直接用于热电发电机（TEG），因为电荷载流子可以通过外部电路有效地从一个电极传输到另一个电极。在本研究中，通过聚丙烯酰胺（PAAM）和聚多巴胺（PDA）的化学交联制备了MIEC水凝胶，形成双网络。此外，通过超声处理以及与PDA的相互作用，将导电的羧基化碳纳米管（CNT - COOH）均匀分散在水凝胶中。此外，通过聚苯胺（PANI）的原位聚合进一步改善了水凝胶的电学性能。CNT - COOH的存在促进了离子电导率，并通过钠离子与CNT - COOH上羧基之间的离子 - 电子相互作用提高了离子塞贝克系数，这可以在X射线光电子能谱结果中观察到，从而促进了电荷传输性能。结果，最佳器件表现出175.3 mS cm的显著离子电导率和18.6 mV K的高离子塞贝克系数，离子功率因子（PF）为6.06 mW m K，相应的离子品质因数（ZT）令人印象深刻，为2.65。这些值代表了凝胶态有机热电材料领域的重大成就。最后，通过将PAAM/PDA/CNT - COOH/PANI水凝胶嵌入聚二甲基硅氧烷模具中制备了可穿戴模块。这种配置产生了171.4 mW m的高功率密度，从而突出了制造能够利用废热的可穿戴设备热电发电机的巨大潜力。
