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

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 d(33) of 347 pC/N and g(33) of 96 x 10(-3) Vm/N, resulting in a higher figure of merit (d(33) x g(33) similar to 33 x 10(-12) m(2)/N) for evaluating energy conversion. The d(33) and g(33) 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 mu W/mm(3), comparable to PZT-based energy harvesters. The enhancement in d(33) 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 epsilon(T)(r3), resulting in increased g(33). The synergistic strategy is expected to facilitate the design high-performing, eco-friendly piezoelectric ceramics.