Highly deformable and hierarchical 3D composite sponge for versatile thermoelectric energy conversion

초록

Adopting organic materials enables the realization of flexible and wearable film-type thermoelectric generators (TEGs) due to high deformability, whereas the low thermoelectric (TE) properties and thin thickness of harvesters impede the realization of multipurpose energy conversion. Herein, flexible and compressible TEGs were designed by the porous TE composite sponges made of coating PVDF-based TE solutions on the porous polymeric template structure. The porous TE sponges were investigated by the change in the concentration of CNTs in the composites, and the applied compressive strains, respectively. The optimized n- and p-type TE sponges showed the power factor of 0.546 nW/mK2 and 3.534 nW/mK2, respectively, under a low compressive strain of 10 %. The electrical response dependent on vertical/horizontal temperature gradient (Delta T) and compressive strain of porous unicouple TEG were measured carefully. The unicouple TEG generates electrical output of 16.08 mV, 0.935 mu A, and 3.92 nW when the vertical Delta T is 70 K. Furthermore, the large-area porous TEGs with an area of 9 x 9 cm2 generates an output power of 0.148 nW from human body heat and 4.22 nW from the overheated vacuum pump. These results pave the way to design other efficient organic-inorganic composite-based TEGs for harnessing the real-time ambient and industrial heat environments.

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