Enhanced piezoelectric energy harvesting performance in BCZT porous ceramics from particle-stabilized foams

Barium calcium zirconate titanate (BCZT) ceramics have attracted significant attention in recent years for their superior piezoelectric properties and potential applications in piezoelectric energy harvesters. However, due to the strong coupling between piezoelectric charge coefficient (d₃₃) and dielectric constant ((Formula presented) ) in dense BCZT ceramics, obtaining a high piezoelectric energy harvesting figure of merit ((Formula presented) ) is still challenging. In this work, we successfully fabricated closed-cell BCZT porous ceramics via a particle-stabilized foaming method with tunable porosities ranging from 66.36% to 84.03%. This optimized microstructure effectively decoupled the traditionally interlinked properties of d₃₃ and (Formula presented), leading to ultrahigh piezoelectric energy harvesting performance with piezoelectric voltage coefficient (g₃₃) of 124.79 × 10⁻³ V m/N and FOM₃₃ of 38.45 × 10⁻¹² m²/N, the output voltage reached a maximum of 246 V and the sensitivity reached 39.11 V/kPa. Compared to dense ceramics, BCZT porous ceramics showed a 4-fold increase in g₃₃ and a 3-fold increase in FOM₃₃. Furthermore, the BCZT porous ceramics demonstrated good compressive strengths up to 13.22 MPa, ensuring robust mechanical integrity. This work offers a promising strategy for the development of porous ceramics with enhanced piezoelectric energy harvesting performances, and highlights the potential of closed-cell BCZT porous ceramics for high-performance energy harvesters.