Flexible Quasi-Solid State Ionogels with Remarkable Seebeck Coefficient and High Thermoelectric Properties
Flexible Quasi-Solid State Ionogels with Remarkable Seebeck Coefficient and High Thermoelectric Properties
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DOI：
10.1002/aenm.201901085
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发表时间：
2019-07-19
影响因子：
27.8
通讯作者：
Ouyang, Jianyong
中科院分区：
文献类型：
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作者：
Cheng, Hanlin;He, Xu;Ouyang, Jianyong
热电材料可以用来收集低品位的热量，否则会散发到环境中。但传统的热电材料，如半导体或半金属，通常表现出塞贝克系数远小于1mv K-1。它们价格昂贵，而且含有有毒元素。在这里，展示了具有巨大塞贝克系数和超高热电性能的环保柔性准固态电离胶。由离子液体和聚偏氟乙烯-共六氟丙烯（PVDF-HFP）制成的离子凝胶可以表现出高达26.1 mV K-1的巨大塞贝克系数，这是电子和离子导体中最高的塞贝克系数。此外，它们具有6.7 mS cm（-1）的高离子电导率和0.176 W m(-1) K-1的低导热系数。因此，它们的热电性能值（ZT）为0.75。巨大的塞贝克系数与PVDF-HFP与离子液体之间的离子偶极相互作用有关。它们在离子热电电容器中的应用也证明了间歇性热转化为电。它们对于获取地球上丰富的低品位热能尤为重要。
Thermoelectric materials can be used to harvest low-grade heat that is otherwise dissipated to the environment. But the conventional thermoelectric materials that are semiconductors or semimetals, usually exhibit a Seebeck coefficient of much less than 1 mV K-1. They are expensive and consist of toxic elements as well. Here, it is demonstrated environmental benign flexible quasi-solid state ionogels with giant Seebeck coefficient and ultrahigh thermoelectric properties. The ionogels made of ionic liquids and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) can exhibit a giant Seebeck coefficient up to 26.1 mV K-1, the highest for electronic and ionic conductors. In addition, they have a high ionic conductivity of 6.7 mS cm(-1) and a low thermal conductivity of 0.176 W m(-1) K-1. Their thermoelectric figure of merit (ZT) is thus 0.75. The giant Seebeck coefficient is related to the ion-dipole interaction between PVDF-HFP and ionic liquids. Their application in ionic thermoelectric capacitors is also demonstrated for the conversion of intermittent heat into electricity. They are especially important to harvest the low-grade thermal energy that is abundant on earth.