Giant Energy Density via Mechanically Tailored Relaxor Ferroelectric Behavior of PZT Thick Film

Relaxor ferroelectrics (RFEs) are being actively investigated for energy-storage applications due to their large electric-field-induced polarization with slim hysteresis and fast energy charging–discharging capability. Here, a novel nanograin engineering approach based upon high kinetic energy deposition is reported, for mechanically inducing the RFE behavior in a normal ferroelectric Pb(Zr_0.52Ti_0.48)O₃ (PZT), which results in simultaneous enhancement in the dielectric breakdown strength (E_DBS) and polarization. Mechanically transformed relaxor thick films with 4 µm thickness exhibit an exceptional E_DBS of 540 MV m⁻¹ and reduced hysteresis with large unsaturated polarization (103.6 µC cm⁻²), resulting in a record high energy-storage density of 124.1 J cm⁻³ and a power density of 64.5 MW cm⁻³. This fundamental advancement is correlated with the generalized nanostructure design that comprises nanocrystalline phases embedded within the amorphous matrix. Microstructure-tailored ferroelectric behavior overcomes the limitations imposed by traditional compositional design methods and provides a feasible pathway for realization of high-performance energy-storage materials.