Enhancement of dielectric constant and piezoelectric coefficient of ceramic–polymer composites by interface chelation

Abstract

Ferroelectric ceramics (e.g., lead zirconate titanate, PZT) and polymers exhibit extraordinary dielectric and piezoelectric properties and processability, respectively. It is, however, difficult to retain the ideal dielectric constant (ε_r) and piezoelectric coefficient (d₃₃) in their composites. Here we show that an interfacial adhesion mechanism (afforded by the chelation technique) in PZT-polymer composites can lead to a dielectric constant that is, remarkably, seven times greater than what is usually found. At frequencies below 40 Hz, the dielectric constant of the composite is higher than in PZT alone (i.e., ε_r > 1300), and this is the first achievement of the ceramic–polymer 0–3 composites as reported. Additionally, a super-high piezoelectric coefficient (d₃₃ > 170) is also obtained owing to the interfacial mechanism. Our finding can lead to a novel way for preparing ceramic–polymer composites with an ultrahigh dielectric constant and ultrahigh piezoelectric coefficient, which are required in many modern electric systems and energy converters.