Giant Electrostriction Enabled by Hydrogen Bond-Induced Active Networks in Relaxor Ferroelectric Nanocomposites

The interconversion between electrical and mechanical energy is the key to ferroelectrics, allowing them to be used in sensors, actuators, and transducers. Ferroelectric polymers exhibit a higher longitudinal strain under an electric field compared to ferroelectric ceramics. However, their mechanical energy density rarely exceeds that of ferroelectric ceramics, severely limiting their usefulness for applications. Here, we introduce carbon dots (CDs) into a relaxor ferroelectric polymer to create an all-organic nanocomposite. The functional groups of CDs enhance interactions with polymer chains, resulting in ultrahigh electrostrictive performance. We demonstrate a longitudinal strain of −6.19% and a mechanical energy density of 0.422 J cm–3 in composites at an electric field of 100 MV m–1. The performances of the terpolymer/CNDs are comparable to those of the best ferroelectric polymer material. This work offers a viable solution to the limitations of ferroelectric polymers, providing new avenues for high-performance flexible electroactive devices in future technological applications.