A Perspective on Multi-Source Energy Harvesting Technology Using Piezoelectric and Thermoelectric Materials

Energy harvesting using various locally available energy sources such as vibration energy, heat, sound, or magnetic field
have become attractive topics for supplying power to modular electronic devices making them run independently in
extreme environments. In this paper, we will be discussing the perspectives on thermoelectric (TE) and piezoelectric
materials and devices, and then the concept of multi-source energy harvester using piezoelectric and thermoelectric devices
and integration of them into a reliable and independent power source. TE materials having low thermal conductivity and
high figure-of-merit (zT) are developed to convert even a small temperature gradient efficiently into electrical energy with
the state-of-the-art conversion efficiency of ~15% and output power of ~56 W from single device. The piezoelectric device
architecture is configured using high performance piezoelectric ceramics (Cu-Mn-PIN-PMN-PT). These ceramics exhibit
high piezoelectric coefficient with high mechanical quality factor and low dielectric loss factor. Using these piezoelectric
materials, power density as high a 2 mW/cm2 is demonstrated in 1-1.5 g vibration environments. The piezoelectric device is attached on the surface of TE module to capture both the vibration and thermal energy sources to realize dual mode
energy harvester. The multi-energy transfer strategy opens opportunities for a future generation of wireless and modular
electronic devices. These devices would be useful in powering wearable electronic devices, micro sensor chargers, etc. in
extreme environmental conditions using body heat/thermal sources and induced motion/vibrations.