With the ever-increasing demand for energy, research on energy storage materials is imperative. Thereinto, dielectric materials are regarded as one of the potential candidates for application in advanced pulsed capacitors by reason of their ultrahigh energy-storage density, low energy loss, and good thermal stability. Among the numerous dielectric materials for energy storage, sodium bismuth titanate (Bi_0.5Na_0.5TiO₃, BNT) with high saturation polarization, as one of the successful alternatives to lead-based materials, has been extensively studied. However, degraded dielectric and ferroelectric properties as a consequence of chemical alterations usually produced by inhomogeneity in microstructure and composition due to the ion volatilization during preparing, thus affecting performance of devices. Hence, this review served to encompass the current state and progress on the optimization of energy storage performance in lead-free BNT-based materials over the past few years, including ceramics, multilayer ceramics, thin films, and thick films, involved in solid solution modification, metal/metallic oxide doping, process optimization and other related aspects to optimize energy storage performance. Furthermore, some prospective approach in the improvement of energy storage performance for BNT-based materials were also provided in this work according to the existing theoretical and experimental results, to impel their practical application.

Water pollution caused by dye wastewater is a potential threat to human health. Using photocatalysis technology to deal with dye wastewater has the advantages of strong purification and no secondary pollution, so it is greatly significant to look for new visible-light photocatalysts with high photocatalytic ability for dye wastewater degradation. Semiconductor photocatalyst silver phosphate (Ag₃PO₄) has high quantum efficiency and photocatalytic degradation activity. However, Ag₃PO₄ is prone to photoelectron corrosion and becomes unstable during photocatalysis, which severely limits its application in this field. In this study, a tubelike g-C₃N₄/Ag₃PO₄ heterojunction was constructed by the chemical precipitation method. An Ag₃PO₄ nanoparticle was loaded onto the surface of the tubelike g-C₃N_4, forming close contact. The photocatalytic activity of the photocatalyst was evaluated by the degradation of RhB under visible-light irradiation. The tubelike g-C₃N₄/Ag₃PO₄-5% heterojunction exhibited optimal photocatalytic performance. In an optimal process, the degradation rate of the RhB is 90% under visible-light irradiation for 40 min. The recycling experiment showed that there was no apparent decrease in the activity of tubelike g-C₃N₄/Ag₃PO₄-5% heterojunction after five consecutive runs. A possible Z-type mechanism is proposed to explain the high activity and stability of the heterojunction.

A multi-step annealing method was successfully applied to inclusions reduction and resistivity improvement of CdMnTe:In (CMT:In) single crystals with high resistivity, including a Cd atmosphere annealing step followed by a Te atmosphere annealing step. After the Cd atmosphere annealing step, the density of Te inclusions was reduced distinctly, and it could be also decreased in the subsequent step of re-annealing under Te atmosphere. Both the resistivity and IR transmittance decreased notably after Cd atmosphere annealing, whereas they increased tremendously after re-annealing under a Te atmosphere. The reduction of full-width at-half-maximum (FWHM) and the increase of the intensity of the X-ray rocking curve indicated an improvement of the crystal quality. Meanwhile, after Cd atmosphere annealing, the increase of the intensity of the (D⁰,X) peak and the disappearance of the (A⁰,X) peak in photoluminescence (PL) measurements suggested further that the crystal quality was improved. The detector performance was enhanced obviously after annealing. The higher the annealing temperature, the better the performance was. The detector fabricated by CMT:In slice (Cd atmosphere annealing at 1073 K for 240 h and Te atmosphere re-annealing at 773 K for 120 h) with 9.43% energy resolution and 1.25 × 10⁻³ cm²/V μτ value had the best detector performance.

Na_0.5Bi_0.5TiO₃ (NBT)-based ceramics are promising lead-free candidates for energy-storage applications due to their outstanding dielectric and ferroelectric properties derived from large polarization. However, the high coercive field and large remnant polarization are unfavorable for practical applications, and thus NBT-based ceramics with relaxation behavior via doping/forming solid solutions with other elements/components have been widely studied. In this work, BaTiO₃ (BT) was introduced to the 0.94Na_0.5Bi_0.5TiO₃-0.06Bi(Mg_2/3Nb_1/3)O₃ system by a conventional solid-state reaction to form a homogeneous solid solution of 0.94[(1−x)Na_0.5Bi_0.51TiO₃-xBaTiO₃]-0.06Bi(Mg_2/3Nb_1/3)O₃ (BNT-100xBT-BMN). As the BT content increased, the proportion of the rhombohedral R3c phase increased while that of the tetragonal P4bm phase decreased, leading to the maximum P_max (38.29 μC/cm²) and E_b (80 kV/cm) obtained in BNT-7BT-BMN (x = 0.07) composition. Specifically, the optimal energy storage properties of W_rec ~ 1.02 J/cm³ and η ~ 62.91% under 80 kV/cm were obtained in BNT-7BT-BMN ceramics, along with good temperature stability up to 200 °C, which are promising factors for future pulse power applications.