Paper‐Templated Porous Piezoceramics

ABSTRACT Targeted porosity design enables deliberate modification of piezoceramics to enhance selected functional properties. Here, we introduce a simple, efficient processing route for porous piezoceramics based on organic paper templating and demonstrate it for Ba(Zr,Ti)O ₃ –(Ba,Ca)TiO ₃ (BZT–BCT). Porosity is tuned from 30% to 60% by adjusting the amounts of polymer filler in the template and the volume of infiltrated ceramic suspension. All porous samples retain the same crystal structure, phase composition, and ferroelectric nature as their dense counterparts. While the polarization, strain, permittivity, and longitudinal piezoelectric coefficient decrease, the hydrostatic piezoelectric coefficient and energy harvesting figure of merit increase. This behavior is attributed to decoupling of the longitudinal and transverse piezoelectric responses and to decreased permittivity. Along with reduced acoustic impedance for improved coupling to water, these gains highlight the suitability of paper‐templated piezoceramics for hydrophones and energy harvesters. The method also enables layered architectures for anisotropic fluid transport and the fabrication of curved structures. Owing to its scalability, low cost, and microstructural tunability, paper templating is broadly applicable to porous electroceramics.