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Pulsed power and power electronics systems used in electric vehicles (EVs) demand high-speed charging and discharging capabilities, as well as a long lifespan for energy storage. To meet these requirements, ferroelectric dielectric capacitors are essential. We prepared lead-free ferroelectric ceramics with varying compositions of (1 − x)Ba0.7Sr0.3TiO3–(x)BiMg0.5Ti0.5O3 (BST–BMT) (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1) using a solid-state-reaction method. To analyze the crystallinity and structural parameters, we examined the X-ray diffraction (XRD) patterns using the pseudo-Voigt function in the FullProf software. Additionally, Raman spectrum analysis confirmed the presence of ceramic structural distortion caused by microstrain and doping. Microstructure images of the ceramic samples showed an increase in grain size from 1 to 2.4 μm and an improved distribution of grain sizes with increasing doping levels. We investigated the dielectric properties of the BST–BMT ceramic capacitors across a wide range of frequencies and temperatures. Interestingly, as the BMT content increased, the previously saturated ferroelectric (FE) curve for x = 0.01 gradually shifted towards a narrower relaxor ferroelectric (RFE) curve for x = 0.1. The most favorable effective energy storage density was observed with a BMT doping concentration of x = 0.04, which coincided with exceptionally high-energy efficiency (η ~ 91%) under a field strength of 50 kV/cm and a relatively high dielectric normalized energy storage density of 3.71 µJV−1 cm−2 due to structural modifications that causes relaxor ferroelectric behavior. More interestingly, the energy storage performance of 0.96BST–0.04BMT displays a fatigue free characteristic enduring through numerous switching cycles. We also calculated the optical bandgap (Eg) values from UV–Vis spectra and compared them with the increase in BMT concentration. The Eg value for all ceramics was approximately 3.2 eV, similar to the pure BST ceramic sample. Additionally, the resistive switching behavior demonstrated by our bulk ceramic capacitors is not commonly observed in other bulk ceramics. [ABSTRACT FROM AUTHOR]

Mechanical energy harvesting and energy storage through lead-free piezoelectric materials is an inevitable source of eco-friendly sustainable powering of electronic devices. Herein, we have synthesized amphoteric rare-earth element praseodymium (Pr) modified Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) ceramics, with a cost-effective solid-state-reaction based two-step sintering method for the controlled grain growth. Their crystalline structures and surface morphology were investigated by using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The dielectric and ferroelectric properties of the ceramic capacitors were investigated and correlated with structural parameters. In the vicinity of the monotonic phase transition region, with the coexistence of orthorhombic and tetragonal symmetry, the Pr ion addition in BCZT improves the tetragonal phase, which widens its energy harvesting and storage arena. The appreciable energy harvesting ability was found for an optimized energy harvester with a composition of 0.04 wt% Pr added BCZT ceramic, with an open-circuit voltage of about 5.1 V (corresponding power density of 1.213 mW/cm3) from a simple finger tapping and bring about output voltage stability with a maximum output voltage of about 9 V over 10,000 cycles when periodic force is applied by a machine tapping. Furthermore, this optimized Pr added BCZT ceramic capacitor is capable of storing a substantial recoverable energy density of 81.9 mJ/cm3with a considerable energy storage efficiency of 76.4%. These upshots offer a head start in implementing these ceramic capacitors for effective energy harvesting and energy storage applications for powering futuristic miniature electronics. ● The amphoteric praseodymium (Pr) modified BCZT ceramics were synthesized through the two-step sintering (TSS) method. ● The dielectric, ferroelectric properties and energy storage behavior got enriched for the Pr modified BCZT ceramics. ● The optimum ceramic-based mechanical energy harvester offers voltage stability of ~ 9 V for 10,000 cycles. ● The recoverable energy density of 81.9 mJ/cm3 and energy efficiency of 76.4% attained. [ABSTRACT FROM AUTHOR]