Model boosts power output of 2D flexible thermoelectric devices

2D flexible thermoelectric devices (FTEDs) work well on curved surfaces and in limited spaces. They may be able to power wearable electronics by harvesting low-grade heat from the human body.

However, the output power of 2D FTEDs is not yet high enough for this application. Researchers must first minimize the internal resistance in these devices to maximize their power generation.

Xu et al. developed a model to optimize 2D FTED performance and used the results to assemble a device capable of milliwatt output power.

Their model systematically considered applied temperature differences, temperature-dependent thermoelectric properties of materials, leg thickness, and thermodynamic conditions to identify optimal parameters and geometries for 2D FETDs. The model predicted 7.3 millimeters is an optimal leg length to minimize internal resistance while maximizing the output power density of a device.

The authors used this optimized design to assemble a 2D FTED achieving a maximum output power of 11.2 milliwatts. The device powered up four light-emitting diodes, demonstrating its potential for harvesting electricity from low-grade heat. The device obtained a normalized output power density much larger than previous 2D FTEDs.

“This research provides a solution for 2D FTEDs under various working conditions and can be extended to other thermoelectric systems to boost the practical applications of FTEDs,” said author Zhi-Gang Chen.

Based on this work, the authors plan to examine the cooling effect of 2D FTEDs and their potential applications as flexible coolers.

Source: “Two-dimensional flexible thermoelectric devices: Using modelling to deliver optimal capability,” by Shengduo Xu, Min Hong, Meng Li, Qiang Sun, Yu Yin, Weidi Liu, Xiaolei Shi, Matthew Dargusch, Jin Zou, and Zhi-Gang Chen, Applied Physics Reviews (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0067930 .