1-mW Vibration Energy Harvester Based on a Cantilever with Printed Polymer Multilayers

Energy harvesters are required for autonomous sensors. The field is still missing a low-cost technology that would provide enough power for tangible low-frequency use cases, although triboelectric nanogenerators (TENG) have emerged as a new energy technology. Standard vibration energy harvesters (VEHs) are based either on bulky electromagnetic systems or stiff lead-based piezo-ceramics. Those systems are rarely compatible with large deformations that occur at low frequency such as body movements. Here, we show that a stack of 10 thin layers of poly(vinylidene fluoride trifluoroethylene) screen printed on a polymer substrate can harvest up to 0.97 mW at 33 Hz with an area of only 2.4 cm2. These results are obtained with a lead-free, cost-effective, and scalable technique at 150°C, competing with TENG solutions. This VEH can work for at least 107 cycles while harvesting sufficient energy to feed a microcontroller that communicate wirelessly with a mobile phone.