The rapidly advancing energy storage performance of dielectric ceramics capacitors has garnered significant interest for applications in fast charge/discharge and high-power electronic techniques. Exploring the exceptional electrical properties in harsh environments can further promote their practical applications. Defect carriers can be excited under luminance irradiation, thereby leading to degradation of energy storage performance. Herein, a synergic optimization strategy is proposed to enhance energy storage properties and luminance resistance of (K_0.5Na_0.5)NbO₃-base (KNN) ceramics. First, the introduction of Bi(Zn_0.5Ti_0.5)O₃ solid solution and La³⁺ ions disrupts the long-range polar orders and enhances super paraelectric relaxation characteristics. Additionally, doping La³⁺ ions can increase the band gap and reduce oxygen vacancy concentration, resulting in excellent luminance resistance. Finally, the viscous polymer process is employed to suppress the grain growth and promote chemical homogeneity. As a result, ultrahigh recoverable energy storage density (W_rec) of 8.11 J/cm³ and high efficiency (η) of 80.98% are achieved under an electric field of 568 kV/cm. Moreover, the variations in W_rec and η are only 12.45% and 1.75%, respectively, under 500 W xenon lamp irradiation compared to the performance under a dark environment. These findings hold great potential in facilitating the practical application of dielectric ceramic capacitors in luminance irradiation environments.

Piezoelectric energy harvesters (PEHs) have attracted significant attention with the ability of converting mechanical energy into electrical energy and power the self-powered microelectronic components. Generally, material's superior energy harvesting performance is closely related to its high transduction coefficient (d₃₃×g₃₃), which is dependent on higher piezoelectric coefficient d₃₃ and lower dielectric constant ε_r of materials. However, the high d₃₃ and low ε_r are difficult to be simultaneously achieved in piezoelectric ceramics. Herein, lead zirconate titanate (PZT) based piezoelectric composites with vertically aligned microchannel structure are constructed by phase-inversion method. The polyvinylidene fluoride (PVDF) and carbon nanotubes (CNTs) are mixed as fillers to fabricate PZT/PVDF&CNTs composites. The unique structure and uniformly distributed CNTs network enhance the polarization and thus improve the d₃₃. The PVDF filler effectively reduce the ε_r. As a consequence, the excellent piezoelectric coefficient (d₃₃ = 595 pC/N) and relatively low dielectric constant (ε_r = 1,603) were obtained in PZT/PVDF&CNTs composites, which generated an ultra-high d₃₃×g₃₃ of 24,942 × 10⁻¹⁵ m²/N. Therefore, the PZT/PVDF&CNTs piezoelectric composites achieve excellent energy harvesting performance (output voltage: 66 V, short current: 39.22 μA, and power density: 1.25 μW/mm²). Our strategy effectively boosts the performance of piezoelectric-polymer composites, which has certain guiding significance for design of energy harvesters.

Oxide-ion conductors have been widely used as catalytic, conductive, detecting and other materials under oxidizing, reducing, inert, mixed environments and the like. However, so far the evaluation of their oxygen-ion transport (such as oxide-ion conductivity and oxygen permeability) either is extrinsic or is limited only in oxidizing or inert environment. Herein, the evaluation of intrinsic oxygen-ion transport for oxide-ion conductors in all environments seems especially important. In this work, a new test system was designed to enable the oxide-ion conductors placing in single oxidizing, reducing, inert or mixed environment separately, which also realized all the oxygen-vacancy concentrations of oxide-ion conductors are in equilibrium in all environments. The intrinsic oxide-ion conductivity and oxygen permeability were evaluated in all environments, and the influencing factors regulated by environments also were analyzed to correlate the variation of oxygen-ion transport.

Although dielectric ceramic capacitors possess attractive properties for high-power energy storage, their pronounced electrostriction effect and high brittleness are conducive to easy initiation and propagation of cracks that significantly deteriorate electrical reliability and lifetime of capacitors in practical applications. Herein, a new strategy for designing relaxor ferroelectric ceramics with K_0.5Na_0.5NbO₃-core/SiO₂-shell structured grains was proposed to simultaneously reduce the electric-field-induced strain and enhance the mechanical strength of the ceramics. The simulation and experiment declared that the bending strength and compression strength of the core-shell structured ceramic were shown to increase by more than 50% over those of the uncoated sample. Meanwhile, the electric-field-induced strain was reduced by almost half after adding the SiO₂ coating. The suppressed electrical deformation and enhanced mechanical strength could alleviate the probability of generation of cracks and prevent their propagation, thus remarkably improving breakdown strength and fatigue endurance of the ceramics. As a result, an ultra-high breakdown strength of 425 kV cm⁻¹ and excellent recoverable energy storage density (Wrec ~ 4.64 J cm^-3) were achieved in the core-shell structured sample. More importantly, the unique structure could enhance the cycling stability of the ceramic (W_rec variation < ±2% after 105 cycles). Thus, mechanical performance optimization via grain structure engineering offers a new paradigm for improving electrical breakdown strength and fatigue endurance of dielectric ceramic capacitors.

The thermal stability and fatigue resistance of piezoelectric ceramics are of great importance for industrialized application. In this study, the electrical properties of (0.99-x)(K_0.48Na_0.52)(Nb_0.975Sb_0.025)O₃- 0.01CaZrO₃-x(Bi_0.5Na_0.5)HfO₃ ceramics are investigated. When x = 0.03, the ceramics exhibit the optimal electrical properties at room temperature and high Curie temperature (T_C = 253 ℃). In addition, the ceramic has outstanding thermal stability (d₃^*₃ ≈ 301 pm/V at 160 ℃) and fatigue resistance (variation of P_r and d₃^*₃ ~10% after 10⁴ electrical cycles). Subsequently, the defect configuration and crystal structure of the ceramics are studied by X-ray diffraction, temperature- dielectric property curves and impedance analysis. On one hand, the doping (Bi_0.5Na_0.5)HfO₃ makes the dielectric constant peaks flatten. On the other hand, the defect concentration and migration are obviously depressed in the doped ceramics. Both of them can enhance the piezoelectrical properties and improve the temperature and cycling reliabilities. The present study reveals that the good piezoelectric properties can be obtained in 0.96(K_0.48Na_0.52)(Nb_0.975Sb_0.025)O₃-0.01CaZrO₃-0.03(Bi_0.5Na_0.5) HfO₃ ceramics.

Garnet-type ceramic electrolyte with exceptionally high Li⁺ conductivity has attracted wide interests for the development of safe electrochemical devices. However, the factors affecting the ionic migration still deserve more attentions. In this study, five garnet-types ceramic electrolyte were chosen to investigate the factors. The thermal behavior of garnet-type electrolyte during sintering was studied to achieve high conductivity. The electrochemical properties are correlated with crystal structure, migrating route and lattice parameters. Nine influening factors were discussed to analyze the ionic migration in garnet-type ceramic electrolyte.