Ultra-high energy harvester performance in KNN-based textured piezoceramics via multiscale reconfiguration design
Caixia Zhu, Jin Qian, Luomeng Tang, Shi Cheng, Boxiong Shen, Jiwei Zhai
Abstract
The lower electromechanical performance of lead-free piezoelectric materials remains a critical bottleneck impeding their ability to replace lead-based materials in energy harvesting. To overcome this predicament, here, we propose a multiscale reconfiguration design to tailor the intricate coupling between structure and properties in (K,Na)NbO<sub>3</sub>-based piezoelectric materials. The constructed multiphase coexistence, local structural heterogeneity, enhanced crystal anisotropy, and acceptor doping yield (K,Na)NbO<sub>3</sub>-based ceramics with a harmonious balance between the piezoelectric coefficient and the dielectric constant. As a result, the (K,Na)NbO<sub>3</sub>-based textured ceramics demonstrate exceptional piezoelectric properties, including a piezoelectric charge coefficient (<em>d</em><sub>33</sub>) of 551 pC N⁻¹ and a piezoelectric voltage coefficient (<em>g</em><sub>33</sub>) of 54.2 mV m N<sup>-1</sup>. The energy harvesting devices exhibit an ultra-high instantaneous output power (<em>P</em><sub>out</sub>) of 4.85 mW and an instantaneous output power density (<em>P</em><sub>D</sub>) of 70.2 μW mm<sup>-3</sup>. This work provides valuable insights into the design and development of high-performance lead-free piezoelectric ceramics, and significantly advances the potential of (K,Na)NbO<sub>3</sub>-based ceramics as viable replacements for Pb(Zr,Ti)O<sub>3</sub>-based ceramics in energy harvesting applications.