Multiscale Heterogeneity Strategy in Piezoceramics for Enhanced Energy Harvesting Performances.

Abstract

Piezoelectric energy harvesters (PEHs) with piezoceramics as the core can convert low-frequency vibration energy that is ubiquitous in the environment into electrical energy and are at the frontier of research in the field of energy. The high piezoelectric charge coefficient (d) together with the large piezoelectric voltage coefficient (g) are essential for enhancing the energy harvesting performances of PEHs working on a nonresonant state. However, conventional doping and solid solution design strategies lead to the same increase or decrease trend of d and dielectric permittivity ε, making it difficult to obtain a high g value because g = d/ε. Herein, exceptionally well-balanced performances of high d and large g are achieved simultaneously in modified Pb(Zr, Ti)O3(PZT)-based ceramics via a multiscale heterogeneity strategy, which involves coordination among the defect dipole, hierarchical domain, and composite. The electromechanical parameters of the optimal specimen are not only superior to those of many state-of-the-art commercial counterparts but also exhibit good thermal stability. Most importantly, the assembled PEH with the optimal specimen shows excellent variable temperature power generation characteristics. This work provides a paradigm for building PEH material through a multiscale heterogeneity strategy, expected to benefit a wide range of electromechanical coupling materials.