Progress in energy storage ceramics for applications has been of interest owing to their clean green nature and excellent ferroelectric/dielectric performances. In this study, lead-free Sm-doped 0.95BaTiO₃–0.05Bi(Mg_0.5Ti_0.5)O₃ (BT–BMT–xSm) relaxor ferroelectric ceramics were synthesized and confirmed to be an appropriate material for storage devices. After the introduction of Sm₂O₃ into BT–BMT ceramics, their hysteresis loops gradually shrank and became slender, which is beneficial to achieving high efficiency energy storage in ceramic capacitors. The maximum recoverable energy density for the BT–BMT–xSm (x = 0.03) sample reached 3.86 J cm⁻³ at normal temperature, and its corresponding energy efficiency reached 81.6%. Moreover, it was found from impedance spectroscopy that the breakdown field strength is related to the oxygen defect content in the samples. Ceramic samples with fewer defects have better insulation performance, which means that a high breakdown field strength will be obtained. With proper doping, enhanced relaxor behaviour and breakdown field strength were obtained to achieve excellent energy storage properties.

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO₂ films. A novel flexible Au/HfO₂/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO₂/Pt/Ti/SiO₂/Si (100) device was also prepared for comparison. The HfO₂ thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO₂ thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.

(1 − x )Pb(Mg _1/3 Nb _2/3 )O ₃ − x PbTiO ₃ ( x = 0, 5, and 10 mol%) ceramics were prepared using a conventional mixed oxide solid state reaction method. The low-temperature relaxor behavior of (1 − x )Pb(Mg _1/3 Nb _2/3 )O ₃ – x PbTiO ₃ ceramics were examined in the temperature range from 120 to 523 K. A broad dielectric maximum that shifted to higher temperatures with increasing frequency, signified the relaxor-type behavior of these ceramics. The value of the relaxation parameter γ = 1.61–1.94 estimated from the linear fit of the modified Curie–Weiss law indicated the relaxor nature. High-temperature dielectric relaxation phenomena were found in the temperature region 600–850 K. Energy-storage properties were also analyzed, and the energy-storage density calculated from hysteresis loops reached about 0.47 J cm ⁻³ at room temperature.