Summary High‐energy ball milling is performed on Li1.1Mn1.95Fe0.05O4 spinel material, synthesized by sol‐gel method for lithium rechargeable battery, at different durations to obtain nanopowders of finite size distributions. The powders are investigated by means of scanning electron microscopy, particle size distribution, and X‐ray diffraction (XRD) measurements. The structural analysis of the powders is performed to investigate the effect of milling on the particle size, crystallite size, and lattice strain. The scanning electron micrographs and size distribution measurements show that the particle size decreases with the increase in milling duration. The XRD results show that the widths of the diffraction peaks increase with the decrease of particle size (increase of milling duration). This broadening is analyzed according to Scherrer, Williamson‐Hall, and Halder‐Wagner methods. Peak broadening is attributed to contributions of crystallite size and lattice strain. While reducing the particle and crystallite sizes is desirable to achieve higher specific capacity and energy density of the battery active material, lattice strain leads to material degradation and a reduced capacity retention. Thus, when performing mechanical milling, lattice strain should be taken seriously into consideration to optimize the milling parameters and to enhance the materials electrochemical performance.

Homogeneous BaTiO 3 fine powder has been synthesized at (80˚C) by using three different chemical methods using the roots TiCl 4 , BaCl 2 and NaOH or Oxalic acid. The resultant powders were characterized using x-ray diffraction (XRD) to estimate the crystal structure, lattice parameters and the crystallite size to investigate the favor method in producing BaTiO 3 fine powder. The criteria that was dependent on considering the favor method that was given better results of XRD and demand a least time in preparation which tend to consume a lowest energy.

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The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications, especially in energy harvesting from crystal vibrations. In order to enhance the performance of BNT ceramic, the solid solution was chosen by substitution with Ba þ2 at Morphtropic Phase Boundary (MPB). The BNT-xBT powders with x ¼ 1, 0.07, 0.06 and 0 were prepared by the hydrothermal method with average particle size (65-150 nm) at (90 C/72 h). The ceramic disc was sintered at (1150 C/4 h) and showed excellent relative density of about 96%. The results of X-ray diffraction (XRD) confirmed the MPB for x ¼ 0:06 and 0.07, while the BNT had a rhombohedral structure and BT had a tetragonal structure. The dielectric measurements showed that BNT, BNT-7BT, BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency, especially in the MPB region while BT behaves as a normal ferroelectric. Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.

Hysteresis loop measurements performed both experimentally for Bismuth Sodium Titanate (BNT) and Bismuth Potassium Titanate (BKT) samples using modified Sawyer-Tower Circuit. The experiment showed that the P-E hysteresis had main parameters for BNT, remnant polarization (P r = 27 µC/cm 2 ), spontaneous polarization (P s = 35 µC/cm 2 ) and coercive electric field (E c = 60 kV/cm) and for BKT the remnant polarization was (P r = 5.2 µC/cm 2 ), spontaneous polarization (P s = 30 µC/cm 2 ) and coercive electric field (E c = 4.72 kV/cm). These three parameters (remnant polarization, spontaneous polarization, coercive electric field) were used in a simulated software depending on the mathematical model for the polarization in ferroelectric materials. The simulation software predicted the value of applied electric field required to perform the P-E hysteresis experiment varying with P r , P s , E c . The results of the simulation exhibited agreement with the experimental data. The last prediction could help the researchers in studying the ferroelectric hysteresis loop, especially for those studying a fatigue behaviour or studying the effect of electric field cycle on the hysteresis loop.