Lead titanate nanowires/polyamide-imide piezoelectric nanocomposites for high-temperature energy harvesting

With an increasing demand for self-powered microelectronics to be used in scientific tasks and exploration missions in extreme environments, the implementation of piezoelectric energy harvesting at high temperature is an important research focus for renewable energy sources. Piezoelectric composites made from piezoelectric ceramic fillers and polymer matrices combine high electromechanical coupling with flexibility, resulting in a versatile candidate for energy harvesting. In this research, a nanocomposite formed by lead titanate nanowires (PbTiO3 NWs) and a polyamide-imide (PAI) matrix is developed and shown to have an excellent piezoelectric response at high temperatures. By in situ measurements of the piezoelectric g31 and d31 coefficients of the nanocomposite films with different PbTiO3 NW weight fractions in the temperature range 25–250 °C, the dependence of temperature and filler concentration on the piezoelectric properties are fully characterized. In addition, the effect of NW alignment on piezoelectric properties through direct ink writing is also studied. Finally, a bending-mode energy harvester made from this nanocomposite is demonstrated to generate a maximum power density of 33 μW·m−2 at resonance and a power density of 20 μW·m−2 under low-frequency random excitation at 200 °C, while keeping a long operating life of at least 100 h. In conclusion, this work provides a new solution for high-temperature energy harvesting from low-frequency random vibrations using PbTiO3/PAI nanocomposites.