Stretchable and Durable Bacterial Cellulose-Based Thermocell with Improved Thermopower Density for Low-Grade Heat Harvesting.

Wu, Zhuotong; Wang, Baoxiu; Li, Jing; Jia, Yuhang; Chen, Shiyan; Wang, Huaping; Chen, Lihui; Shuai, Li · Nano Lett · 2023

basic_science · Level V

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Abstract

Low-grade heat exists ubiquitously in the environment, and gel-state thermogalvanic cells (GTCs) can directly convert thermal energy into electricity by a redox reaction. However, their low ionic conductivity and poor mechanical properties are still insufficient for their potential applications. Here, we designed a bacterial cellulose (BC) nanofiber-macromolecular entanglement network to balance the GTC's thermopower and mechanical properties. Therefore, the BC-GTC shows a Seebeck coefficient of 3.84 mV K<sup>-1</sup>, an ionic conductivity of 108.5 mS cm<sup>-1</sup>, and a high specific output power density of 1760 μW m<sup>-2</sup> K<sup>-2</sup>, which are much higher than most current literature. Further connecting 15 units of BC-GTCs, the output voltage of 3.35 V can be obtained at a temperature gradient of 65 K, which can directly power electronic devices such as electronic calculators, thermohydrometers, fans, and light-emitting diodes (LEDs). This work offers a promising method for developing high-performance and durable GTC in sustainable green energy.