High-temperature piezoelectric conversion using thermally stabilized electrospun polyacrylonitrile membranes

Abstract

Polymer materials with mechanical energy-to-electricity conversion capability at high temperatures are highly desirable to develop energy harvesters, sensors, and other flexible devices for applications under harsh high-temperature conditions but remain an enormous challenge to develop. Herein, we report a polymer membrane that can convert mechanical energy into electricity at both room and high temperatures. The membranes were prepared by heat stabilization treatment of electrospun polyacrylonitrile (PAN) fibrous membranes to make PAN have a cyclized structure. The devices made of the treated PAN membranes can work at a temperature as high as 550 °C, which has never been reported on other polymer-based energy harvesting devices so far. A 2.5 × 2.5 cm² device at 450 °C can generate a 9.7 V voltage (up to 62 V, 4 μA current) with a maximum power density of 26.4 mW cm⁻². We further show that the oxidation cyclization of PAN due to stabilization treatment plays an essential role in achieving the high-temperature energy conversion. The energy conversion is mainly originated from a piezoelectric effect. We used the energy generated under high-temperature conditions to power commercial LEDs and charged capacitors to demonstrate the application. The electrical energy generated from a single device is sufficient to run a commercial LEDs. After rectification, it can also be stored in capacitors for further use. The PAN membranes are flexible and air permeable. They may form a novel polymer transducer candidate to develop flexible energy devices for various applications in high-temperature environments.