Optimization of high-performance flexible thermoelectric generator from material synthesis to simulation and device application

Abstract

Recently, flexible thermoelectric (f-TEG) power generators have attracted great attention due to their ability to capture waste heat from curved heat sources and convert it into useful electrical power. This study presents the material synthesis, theoretical optimization, module fabrication, and device application of a high-performance f-TEG. Firstly, n-type Bi2Te2.7Se0.3 and p-type Sb1.5Bi0.5Te3 TE materials were synthesized via a low-cost and fast fabrication process of mechanical alloying, cold pressed followed by a sintering process. The n-type and p-type materials exhibit maximum ZT values of 0.7 and 1.1, respectively. Then, the transport properties were used to optimize the geometry of the f-TEG in COMSOL Multiphysics. Based on the optimized parameters, a flexible module was developed which consists of 70 thermocouples each has a leg dimension of 1 × 1.5 × 2 mm3. The fabricated f-TEG measured on the arm generates an open circuit voltage, and power output of 93 mV, and 556 µW, respectively, at a temperature difference of 10 °C. The device was tested with a custom-made two-wire wireless ECG (electrocardiogram) and TEG harvester. Charge and discharge times of the supercapacitor and the efficiency of the TEG harvester were determined for the temperature difference of 10 °C. The test results show that the f-TEG can generate enough power to supply energy to the wireless ECG, but the efficiency of the boost converter is as low as 20%.