Processing of hybrid shape memory alloy coupled with P(VDF-TrFE) piezoelectric polymer composite for energy harvesting application

Abstract

Small-scale energy harvesting to power self-powered electronic devices is tremendously increasing. In this context, the ability to combine thermal and mechanical energy harvesting using smart materials deserves more attention for further study. We have presented the feasibility of using P(VDF-TrFE) piezoelectric polymer coupled with NiTi shape memory alloy (SMA) to harvest both mechanical and thermal energy in simple scalable devices. A novel hybrid composite consisting of SMA, and P(VDF-TrFE) has been developed without any complex composites or patterned structures, which couples the piezoelectric effect of the poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) and the shape memory effects of NiTi SMA. We have also fabricated a multi-layer SMA/PEN/P(VDF-TrFE) device using epoxy as an interface and bonding layer. During bending, the P(VDF-TrFE) device with an active area of 3.68 cm² generated an output voltage of 8 V and an output power of 6.25 µW. When coupled with NiTi SMA to create a hybrid composite thermoelectric material, the device can convert the phase change associated with SMA, and thus thermal energy is converted to mechanical energy and finally into electrical energy. The SMA/P(VDF-TrFE) hybrid composite produced an output voltage of ∼2 V for one cyclic heating and cooling of the device. This is a promising approach for the further development of coupled hybrid energy harvester devices for the powering of small-scale electronic devices such as sensors, MEMS, or biomedical devices.