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The dielectric capacitors with excellent energy storage characteristics, high power density and temperature stability are strongly desired in modern pulse power system and electronic industry. Thus, BKNAS- x PbO glass-ceramics were designed and prepared. Free oxygen in the glass phase which weakens the glass network structure can be adsorbed by trace Pb2+, thus improving the breakdown strength (BDS) of BKNAS glass-ceramics. Extremely high BDS (~2089 kV/cm) and excellent energy storage density (~17.62 J/cm3) were achieved in 0.6 mol% PbO doped BKNAS glass-ceramics. Moreover, the permittivity variance of BKNAS-0.6PbO glass-ceramics was less than 4.39% in the ultrawide temperature range (−80–300 °C), suggesting excellent temperature stability. The single layer capacitor made by BKNAS-0.6PbO glass-ceramics also exhibited excellent charge-discharge performance, in which the underdamped discharge power density reached 133.69 MW/cm3 as well as the overdamped discharge power density reached 146.89 MW/cm3 with ultrashort discharge time (<18 ns). The above results show that BKNAS-0.6PbO glass-ceramics possesses great potentiality for pulse capacitors owning to excellent energy storage property, temperature stability and charge-discharge performance. [ABSTRACT FROM AUTHOR]

SrO–Na2O–Nb2O5–SiO2 (SNNS) glass–ceramics with Ta2O5 dopants were prepared by a method of conventional melt-quenching and crystallization. The effects of different contents of Ta2O5 dopants on the microstructures, dielectric properties, energy storage densities and discharge properties of SNNS glass–ceramics were exhaustively investigated. Results showed that the doping of Ta5+ cations can significantly improve the dielectric constant of SNNS glass–ceramics, attributing to the increase in NaNbO3 precipitation. In addition, an optimal amount of Ta2O5 doping can effectively reduce the grain agglomeration of the glass–ceramics and improve their electric breakdown strength. A maximum theoretical energy storage density reached 15.22 J cm–3 over SNNS glass–ceramics with 2 mol% of Ta2O5 dopants; in particular, approximately 0.41% of ultra-low dielectric loss was obtained in this composition. Besides, a tremendous instantaneous power density of 125 MW cm–3 was achieved at 400 kV cm–1 electric field in the single-layer capacitor based on those SNNS glass–ceramics, as well as a rapid discharge time of 10 ns. All these outcomes demonstrate the doped SNNS glass–ceramics have a giant potential for pulse power applications. [ABSTRACT FROM AUTHOR]

The SrO-BaO-Nb 2 O 5 -SiO 2 glass-ceramics with different (Sr, Ba)/Nb ratio were prepared by the melting-crystallized process. With the decrease of (Sr, Ba)/Nb, the bonding species and crystallization activation energy of the glass-ceramics were changed obviously, which caused the change of phase compositions and microstructures on a microscopic scale and the fluctuations of dielectric constant and breakdown strength on a macroscopic scale. Finally, the theoretical energy storage density was up to 18.93 J/cm3 with a dielectric constant of 84 and breakdown strength of 2256.73 kV/cm. What is more, the dielectric loss was less than 0.004 at room temperature. Furthermore, under the electric field of 640 kV/cm the discharge energy density of the optimal sample (S5) reached 1.14 J/cm3 which overtopped what has been reported and the discharge time (t 0.9) was less than 16 ns. Above analysis suggested that the alkali-free niobate-based glass-ceramics have broad application prospects. [Display omitted] [ABSTRACT FROM AUTHOR]

Glass-ceramics show a great application potential in sustainable development, environmental protection, high temperature, high voltage resistance, and so on. Given the breakdown strength has a great contribution to the energy storage density, alkali-free niobate-based glass-ceramics have emerged as a prominent energy storage material. In this study, the 13.64BaCO 3 -13.64SrCO 3 -32.72Nb 2 O 5 -40SiO 2 alkali-free glass-ceramics were optimized in thickness and crystallization temperature. The thinning of thickness improves the breakdown strength. At the same time, the dielectric constant gets a maximum value by adjusting the crystallization temperature. Therefore, an ultra-high theoretical energy storage density of 27.47 J·cm−3 is obtained. In addition, the finite element software simulates the electric field distribution and electric potential evolution during the development of electric branches, which illustrates the role of glass phase in hindering the development of electric branches and partaking the high electric field. Finally, the effective energy storage density obtained by using P-E loops is 1.49 J·cm−3 under 850 kV/cm. [Display omitted] [ABSTRACT FROM AUTHOR]

The niobate-based alkali-free ferroelectric glass-ceramics were realized through the synthesis of mother glass by way of melt-annealing technique, followed by temperature-controlled crystallization. As the crystallization temperature raised, the ratio of the ferroelectric crystal phase precipitated in the mother glass enhanced continuously, resulting in the enlargement of the permittivity. Attribute to the rise of grain size, pores and cracks tend to appear in the microstructure of glass-ceramics with high crystallization temperature, leading to lower breakdown strength. The theoretical simulation was applied to reveal the internal mechanism, exploring the outcome of heat treatment temperature on the breakdown electric field. The maximum theoretical energy storage density reaches to 18.44 J/cm3 at the crystallization temperature of 800 °C. The single-layer capacitor made from the G800 sample exhibited extremely high power density (230 MW/cm3) and superior actual discharge energy density (1.5 J/cm3) at 600 kV/cm. These results indicate that alkali-free niobate-based glass-ceramics is a kind of encouraging candidate material for pulse capacitors. • Focused on the rarely researched direction of alkali-free niobate glass-ceramics. • The finite element method was used to reveal the micromechanism of breakdown. • Revealed the change of crystallization temperature on phase structures. • Both high power density and actual discharge energy density were obtained in this research system. [ABSTRACT FROM AUTHOR]