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Open Access Research Article Issue
Simultaneously enhanced energy storage performance and luminance resistance in (K0.5Na0.5)NbO3-based ceramics via synergistic optimization strategy
Journal of Advanced Ceramics 2024, 13 (1): 34-43
Published: 18 January 2024
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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 (K0.5Na0.5)NbO3-base (KNN) ceramics. First, the introduction of Bi(Zn0.5Ti0.5)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 (Wrec) 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 Wrec 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.

Open Access Research paper Issue
Achieving excellent energy storage reliability and endurance via mechanical performance optimization strategy in engineered ceramics with core-shell grain structure
Journal of Materiomics 2022, 8 (3): 601-610
Published: 30 November 2021
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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 K0.5Na0.5NbO3-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 (Wrec 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.

Open Access Research Article Issue
Enhanced thermal and cycling reliabilities in (K,Na)(Nb,Sb)O3-CaZrO3-(Bi,Na)HfO3 ceramics
Journal of Advanced Ceramics 2020, 9 (3): 349-359
Published: 05 June 2020
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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)(K0.48Na0.52)(Nb0.975Sb0.025)O3- 0.01CaZrO3-x(Bi0.5Na0.5)HfO3 ceramics are investigated. When x = 0.03, the ceramics exhibit the optimal electrical properties at room temperature and high Curie temperature (TC = 253 ℃). In addition, the ceramic has outstanding thermal stability (d3*3 ≈ 301 pm/V at 160 ℃) and fatigue resistance (variation of Pr 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 (Bi0.5Na0.5)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(K0.48Na0.52)(Nb0.975Sb0.025)O3-0.01CaZrO3-0.03(Bi0.5Na0.5) HfO3 ceramics.

Open Access Research Article Issue
Factors influencing Li+ migration in garnet-type ceramic electrolytes
Journal of Materiomics 2019, 5 (2): 214-220
Published: 20 December 2018
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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.

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