Improved energy-harvesting performance of (K, Na)NbO3-based ceramics through the synergistic effect of texture and defect engineering

Abstract

Textured CuO-doped KNN-based ceramics with [001]C orientation were developed to enhance energy harvesting performance. Textured ceramics doped with 0.3 mol% CuO exhibit remarkable piezoelectric coefficients d33 of 347 pC/N and g33 of 96 × 10−3 Vm/N, resulting in a higher figure of merit (d33 × g33 ∼ 33 × 10−12 m2/N) for evaluating energy conversion. The d33 and g33 increased by 105 % and 269 %, respectively, compared to those of randomly oriented ceramics. The piezoelectric energy harvester fabricated using the textured ceramic achieved an output power density of 3 μW/mm3, comparable to PZT-based energy harvesters. The enhancement in d33 is mainly due to favorable [00 l]C orientation. The orientation, along with the hardening effect caused by CuO doping, contributes to decreased dielectric coefficient εTr3, resulting in increased g33. The synergistic strategy is expected to facilitate the design high-performing, eco-friendly piezoelectric ceramics.