High-Performance Thermoelectric Composite of Bi<sub>2</sub>Te<sub>3</sub> Nanosheets and Carbon Aerogel for Harvesting of Environmental Electromagnetic Energy
Hui Long, Yongxin Qian, Shuangfu Gang, Wenguang Zhang, Boyu Yang, Yingchao Wei, Bo Wang, Li Wang, Qinghui Jiang
Abstract
Intensifying the severity of electromagnetic (EM) pollution in the environment represents a significant threat to human health and results in considerable energy wastage. Here, we provide a strategy for electricity generation from heat generated by electromagnetic wave radiation captured from the surrounding environment that can reduce the level of electromagnetic pollution while alleviating the energy crisis. We prepared a porous, elastomeric, and lightweight Bi 2 Te 3 /carbon aerogel (CN@Bi 2 Te 3 ) by a simple strategy of induced in situ growth of Bi 2 Te 3 nanosheets with three-dimensional (3D) carbon structure, realizing the coupling of electromagnetic wave absorption (EMA) and thermoelectric (TE) properties. With ultra-low thermal conductivity (0.07 W m –1 K –1 ), the CN@Bi 2 Te 3 composites achieved a minimum reflection loss (RL) of 51.30 dB and an effective absorption bandwidth (EAB) of 6.20 GHz at an optimal thickness of 2.8 mm. Additionally, under a temperature gradient of 80 K, the flexible thermoelectric generator (FTEG) system generates a maximum output power of 42.2 μW. By absorbing 2.45 GHz microwaves to build the temperature difference, the EMA-TE-coupled device achieves an optimal U oc of 38.4 mV, a short-circuit current of 1.03 mA, and an output power of 9.87 μW upon a radiation time of 50 s. This work establishes a potential pathway for further recycling electromagnetic energy in the environment, which is also promising for the preparation of large-area flexible EM to electrical energy conversion devices.