Harnessing the Morphotropic Phase Boundary in (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ Perovskites for Piezoelectric Energy Harvesting: Experimental and DFT Investigations

Achieving breakthroughs in lead-free piezoelectric materials requires precise control over phase coexistence and intrinsic defect structures. Here, we unveil the design and application of (Ba 0.85 Ca 0.15 )(Zr 0.1 Ti 0.9 )O 3 (BCZT) ceramics, leveraging multiphase engineering at the morphotropic phase boundary (MPB) to actualize ceramic-based piezoelectric energy harvesting (PEH). A distinct mixed-phase region is revealed where rhombohedral, orthorhombic, and tetragonal phases coexist and are stabilized by oxygen vacancy modulation at grain boundaries. This unique phase coexistence drives enhanced polarization rotation and strain response, marking a key innovation in optimizing BCZT ceramics for energy harvesting applications. Mechanical analysis uncovered a transition from elastic to plastic deformation, while temperature-dependent mobility and resistivity studies highlighted a sharp phase transition near the Curie temperature, offering fresh insights into domain dynamics under thermal stimuli. The ability of the BCZT-based PEH prototype to harvest energy efficiently under mechanical stress, coupled with integration into energy devices using a full-bridge rectifier and a capacitor, exemplifies its transformative potential in low-power electronics and self-sustaining systems. This work establishes BCZT ceramics as a promising platform, combining structural innovation and functional excellence to address the growing demand for sustainable, high-performance energy harvesting technologies.