Niobate-based Glass Ceramics Research Articles

Enhanced energy storage and mechanical properties in niobate-based glass-ceramics

The advancement of energy storage glass-ceramics, serving as quintessential elements within pulse power capacitors, is deemed essential for the progression of sophisticated electronic systems, attributable to their ultrafast discharge rate and elevated dielectric breakdown strength (DBS). In this study, the incorporation of 1.2 mol% Nd2O3 into SiO2-Na2O-K2O-BaO-Nb2O5-Nd2O3 (SNKBNN) glass-ceramics has significantly enhanced the material performance. Specifically, a high recoverable energy storage density (Wrec) of 2.06 J/cm3 can be achieved, alongside an ultrahigh efficiency (η) of 92.3 % under an electric field of 630 kV/cm. Additionally, this glass-ceramics also exhibit a high discharge energy density (Wd) of 0.97 J/cm3, an ultrafast discharge rate of 7 ns, and an exceptionally high hardness (Hv) of 10.51 GPa. Additionally, these glass-ceramics exhibit exceptional stability across a range of temperatures (25 to 150 ℃), frequencies (10 to 1000 Hz), and cycling durability (up to 104 cycles). The research has corroborated the structural interdependence between energy storage and mechanical properties, establishing a foundational understanding of their synergistic relationship. The synthesized glass-ceramics demonstrate significant potential for use in high-power dielectric capacitors.

Engineering Phase Separation in Niobate Glass through Ab Initio Molecular Dynamics for Enhanced Energy Storage Performance and Unprecedented Thermal Stability in Niobate-Based Glass Ceramics.

The advancement of lead-free glass ceramics (GCs) possessing appropriate energy storage characteristics is crucial for the renewable energy and electronics industry. In this study, we synthesized lead-free GCs predominantly composed of the tungsten bronze phase, Ba3.3Nb10O28.3. Ab initio molecular dynamics initially reveal nonuniform distribution within the Ba/Nb-O regions in niobite glassy melts, offering valuable insights for the subsequent crystallization process. The proposal of a B-site engineering strategy is suggested, which entails the concurrent reduction of grain size and augmentation of the band gap in tungsten bronze GCs doped with Ta. This approach results in a substantial enhancement of the dielectric breakdown strength (BDS). Phase-field simulations have indicated that the refinement of grain sizes plays a pivotal role in augmenting the local electric field distribution and breakdown path, thereby contributing to the enhancement of BDS. As a consequence of these modifications, a notably high recoverable energy density (Wrec) of 5.23 J/cm3 can be achieved, accompanied by an ultrahigh efficiency (η) of 94%, and superior thermal stability in energy storage. These outcomes are particularly evident in the case of 2 mol % Ta2O5-doped P2O5-K2O-BaO-Bi2O3-TeO2-Nb2O5 (PKBBTN-T) GCs, where the Wrec and η can be determined to be 2.87 ± 3% J/cm3 and 95.46 ± 4%, respectively, over a temperature range spanning from 20 to 150 °C. Additionally, this specimen exhibits an exceptionally high discharge energy density (Wdis) of 4.01 J/cm3. This comprehensive investigation, comprising experimental and theoretical analyses, establishes an effective pathway and paradigm for the development of dielectric materials with ultrahigh energy storage properties.

Greatly enhanced energy storage density of alkali-free glass-ceramics after dual optimizations by thickness and crystallization temperature

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 13.64BaCO3-13.64SrCO3-32.72Nb2O5-40SiO2 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.

High discharge energy density and ultralow dielectric loss in alkali-free niobate-based glass-ceramics by composition optimization

The SrO-BaO-Nb2O5-SiO2 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 (t0.9) was less than 16 ns. Above analysis suggested that the alkali-free niobate-based glass-ceramics have broad application prospects.

Achieving ultrafast discharge speed and excellent energy storage efficiency in environmentally friendly niobate-based glass ceramics

Environmentally friendly Na2O–BaO–Nb2O5–SiO2 glass ceramics (GCs) with different vanadium pentoxide (V2O5) contents were successfully synthesized using the conventional melt-quenching method and heat treatment. The microstructure and dielectric energy storage properties of the GCs could be related to the addition of V2O5. When 1 mol% of V2O5 was added, the activation energy of crystallization decreased from 282 to 221 kJ/mol, and the GCs had the highest energy efficiency of 95.96% and breakdown strength of 1326 kV/cm. Moreover, the GCs could also achieve an ultrafast discharge time of 14 ns and an actual discharge energy density of 0.724 J/cm3. These results indicate that these environmentally friendly GCs can be used in energy storage devices.

Crystallization-temperature controlled alkali-free niobate glass-ceramics with high energy storage density and actual discharge energy density

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.

Excellent energy storage performance of niobate-based glass-ceramics via introduction of nucleating agent

For glass-ceramics, how to realize the collaborative optimization of BDS and permittivity is the key to improve the energy storage density. In this work, ZrO2 is introduced into BPKNAS glass-ceramics as nucleating agent to promote crystal development of glass-ceramics and then achieve high permittivity. When 1.5 mol% ZrO2 is added, the glass-ceramics have the highest permittivity (∼128.59) and meanwhile possess high BDS (1948.90 kV/cm) due to the dense microstructure. Therefore, BPKNAS-1.5ZrO2 glass-ceramics has the highest theoretical energy storage density (21.62 J/cm3). Moreover, the permittivity variation of BPKNAS-1.5ZrO2 glass-ceramics is less than 6 % in the wide temperature range from −80 to 300 °C, showing excellent temperature stability. In addition, BPKNAS-1.5ZrO2 glass-ceramics possesses ultrahigh power density, which reaches up to 382.40 MW/cm3 in overdamped circuit. The above evidence shows that BPKNAS-1.5ZrO2 glass-ceramics with ultrahigh energy storage density and power density is very competitive in the field of energy storage applications.

Optimizing the energy storage and charge-discharge performance of borate glass-ceramics by adjusting the glass structure

In this work, the niobate-based borate glass-ceramic system K 2 O–Na 2 O–Nb 2 O 5 –B 2 O 3 was proposed for the first time, in which the presence of alkali metal oxides not only tends to form ferroelectric crystalline phase to obtain high permittivity, but also optimizes the borate glass network structure to enhance the breakdown strength. The change of borate glass network structure and the influence on conductivity and carriers migrate is systematically discussed. The results show that the high breakdown performance is attributed to the transformation from [B∅ 2 O − ] triangle to [B∅ 4 ] - tetrahedron realizes the high extent of glass network polymerization, which effectively impedes carriers migration and reduces the conductivity. The high permittivity and low dielectric loss are obtained in the range of room temperature to 200 °C. Compared to other niobate-based glass-ceramics, the potassium sodium niobate borate glass-ceramic simultaneously achieve high discharge energy density, high power density and rapid discharge rate (∼14 ns).

Achieving ultrahigh discharge energy and power density in niobate-based glass ceramics via A-site substitution modulation during crystallization

Ultra-high energy and power density can be obtained by A-site substitution modulation in glass ceramics.

High breakdown strength and enhanced energy storage performance of niobate-based glass-ceramics via glass phase structure optimization

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-xPbO 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.

Simultaneously ultra-low dielectric loss and rapid discharge time in Ta2O5 doped niobate-based glass–ceramics

Simultaneously ultra-low dielectric loss and rapid discharge time in Ta2O5 doped niobate-based glass–ceramics

Achieving Superior Energy Storage Properties and Ultrafast Discharge Speed in Environment-Friendly Niobate-Based Glass Ceramics.

Glass ceramics composed of Na2O-BaO-Bi2O3-Nb2O5-Al2O3-SiO2 (NBBN-AS) were modified by rare-earth doping and prepared via the melt-quenching process accompanied by controlled crystallization. High-resolution transmission electron microscopy displayed the glassy matrix closely encompassing the nanosized NaNbO3, Ba2NaNb5O15, BaAl2Si2O8, and AlNbO4 crystalline grains. With rare-earth doping, the NBBN-AS glass ceramics' theoretical energy storage density can reach 22.48 J/cm3. This excellent energy storage property is credited with increasing breakdown strength, and numerical simulation was applied to reveal the intrinsic mechanism for increased breakdown strength by rare-earth doping. The charge-discharge results indicated a giant power density of 220 MW/cm3 as well as an ultrafast discharge speed of 11 ns. The results indicate that the glass ceramic can be used in advanced capacitor applications.

Optimizing the energy storage performance of K2O–Nb2O5–SiO2 based glass-ceramics with excellent temperature stability

Glass-ceramics possessing high power density, energy density and fast charge-discharge rate during a wide temperature range are considered to be the ideal materials for pulse power applications. Under the premise of negligible effect on the glass network structure, the energy storage performance was improved by introducing Na+ ions, which reduced the carrier mobility and the conductivity in this study. The potassium sodium niobate silicate initial glass were synthesized by the traditional melting method, and the glass-ceramics were prepared by the crystallization treatment at 800 °C for 2 h. Introducing sodium ions promoted the formation of Na0.35K0.65NbO3 phase, and increased the permittivity to 104 simultaneously. Superior high breakdown strength (750 kV/cm) was obtained because of the competition between two physical mechanisms of electrical conductivity and micromorphology. When the sodium oxide content was 0.375, the discharge energy density of 2.44 J/cm3 and high energy storage efficiency of 93% were obtained. Compared with ceramics, polymers and other niobate-based glass-ceramics reported currently, this work had achieved high actual discharge energy density (0.156 J/cm3) and high power density (19.6 MW/cm3) under low field strength, and had an extremely fast discharge rate (~14 ns) and excellent wide temperature stability (20–120 °C).

Crystallization Mechanisms and Energy-Storage Performances in BaO-SrO-Na2O-Nb2O5 Based Glass–Ceramics

The [x BaO, (1 − x) SrO]-Na2O (x = 0.0, 0.2, 0.5, 0.8) niobate-based glass–ceramics were prepared through the controlled crystallization method. Crystallization mechanism, phase structure, dielectric properties, and energy-storage properties were studied by adjusting Ba/Sr ratio. It was found that the surface and internal crystallization occurred simultaneously at first crystallization peak, while surface crystallization occurred at second crystallization peak. With Ba/Sr ratio increasing, dielectric constant increased firstly and then decreased, while dielectric loss firstly decreased and then increased. When x = 0.2, optimal dielectric constant of 88 and dielectric loss of 0.0055 were obtained, which is related to the solid solution phase Sr0.5Ba0.5Nb2O6. Breakdown strength (BDS) showed a behavior of increase before decrease. The highest BDS reaches 1975 kV/cm for x = 0.2, which is attributed to uniform and dense microstructure. Correspondingly, the theoretical energy-storage density was increased up to 15.4 J/cm3. Also, discharged efficiency reaches a high value of 91%. Discharged power density of 0.65 MV/cm3 was obtained for x = 0.2 in the RLC pulsed circuit.

Large improvement on energy storage and charge-discharge properties of Gd2O3-doped BaO-K2O-Nb2O5-SiO2 glass-ceramic dielectrics

Potassium barium niobate-based glass ceramics doped with different proportion of Gd2O3 were fabricated by conventional melts and controllable crystallization. The influence of Gd2O3 content was further investigated on the phase compositional change, energy storage performance and charge-discharge properties of the optimized glass ceramics (crystallization temperature 900°C). The microstructure has been remarkably transformed through the addition of Gd2O3. On the basis of the results, the doping of 1.0% Gd2O3 achieved a remarkable improvement on the energy storage density that reached 12.14J/cm3 with a dielectric breakdown strength (BDS) of 1818kV/cm and dielectric constant of 83. The discharge efficiency of 80% and discharge time of 25ns were obtained in the glass ceramics with 1.0% Gd2O3, which illustrated the excellent charge-discharge properties of Gd2O3-doped glass ceramics.

Crystallization kinetics, breakdown strength, and energy-storage properties in niobate-based glass-ceramics

In this work, (100-x)(0.12 SrO-0.3 Na2O-0.1 Nb2O5)-xSiO2 (x = 30, 35, 40, 45, 50 mol%) glass-ceramics were prepared by using the meth-quenching-controlled crystallization method. Phase evolution, Crystallization mechanism, dielectric properties, dielectric breakdown strength (DBS), and energy-storage performances were comprehensively studied by varying SiO2 content. DSC studies revealed simultaneous occurrence of surface and internal crystallization mechanism in the glass-ceramics. XRD results showed three tungsten bronze structure SrNb2O6, Sr6Nb10O30, NaSr2Nb5O15 phases and perovskite structure NaNbO3 phase, which was quantified by the Reietveld refinement. It was found that dielectric constant and theoretical energy-storage density increased firstly and then decreased with the increase of the SiO2 contents. For x = 35 mol%, the theoretical energy-storage density reaches the maximal value of 15.3 J/cm3 due to the highest dielectric constant of 124 and DBS of 1669 kV/cm. And the highest DBS is related to the uniform and dense microstructure for x = 35 mol%. For practical applications in pulsed RLC circuit, the discharged efficiency increases from 74.2% to 91.5% with the increase of the SiO2 contents.

The Structure, Dielectric and Energy Storage Properties of Strontium Barium Niobate-Based Glass–Ceramics Doped with La2O3

In this work, the effect of La2O3 content on the phase evolution, microstructure, dielectric properties and energy storage properties of the strontium barium niobate (SBN)-based glass–ceramics were studied. The results show that the La3+ is easily incorporated into the tetragonal tungsten bronze structured phase, and La2O3 doped into the BSN-glass–ceramics, as a grain growth inhibitor, can have an evident effect on the grain size reduction and crystallization. The microstructure of the SBN-glass–ceramics becomes denser and more uniform with increasing La2O3 content. The remanent polarization of all samples is extremely low. The dielectric constant of the SBN-glass–ceramics obviously is decreased, while the breakdown strength is increased with the increment of La2O3 content. When La2O3 content in the SBN-glass–ceramics is 0.2 mol.%, the theoretical energy storage density is at the maximal level of 7.2 J/cm3. In addition, the energy discharging efficiency and discharging speed of the SBN-glass–ceramics with different La2O3 content were evaluated. With La2O3 content increasing, the energy discharging efficiency gradually increased.

Enhanced energy storage density and discharge efficiency in the strontium sodium niobate-based glass-ceramics

The niobate-based glass-ceramics with a high energy storage density were prepared by using the controlled crystallization technology in the (Na2O, SrO)Nb2O5SiO2 glass-ceramics. The dielectric properties, energy storage density, and discharge properties were investigated with the variation of the Na/Sr molar ratio. By varying the Na/Sr ratio, the energy storage density raises up to a high value of 10.09 J/cm3. With the variation of the Na/Sr ratio, both dielectric breakdown strength and discharge efficiency have an opposite change trend with the activation energy that reflects the interface polarization of the glass-ceramics. In contrast, for Na/Sr = 1/2, the glass-ceramic has the lower activation energy, which indicates that its interfacial polarization is weaker due to a fine microstructure. Thus, the glass-ceramics for Na/Sr = 1/2 have the characteristics of the higher breakdown strength of 2074 kV/cm and the higher discharge efficiency of 90.1%. Then it may contribute to the high energy storage density capacitor.

Crystallization kinetics behaviour and dielectric properties of strontium barium niobate-based glass–ceramics

Strontium barium niobate-based glass–ceramics (SBN–glass–ceramics) with various B2O3/SiO2 ratios have been prepared by powder-melting method followed by controlled crystallization. The effects of different B2O3/SiO2 ratios on the phase evolution, microstructure, dielectric property, breakdown strength and energy storage density of the SBN–glass–ceramics were studied. In addition, the crystallization kinetics behavior of the SBN–glass was analyzed by differential scanning calorimeter method. The microstructure of the SBN–glass–ceramics by replacing SiO2 with B2O3 becomes dense and uniform dramatically. Through the analysis of the crystallization kinetics, replacing a small amount of SiO2 with B2O3 can make the SBN–glass less stable, which is conducive to crystallization in the SBN–glass. When the ratio of B2O3/SiO2 is 1.5/33.5 in the SBN–glass–ceramics, the dielectric constant is up to 143.2 and the optimized theoretical energy storage density of 7.4 J/cm3 is achieved at room temperature, which is about 2 times higher than that of the boron-free SBN–glass–ceramics.

Effect of Different Al/Si Ratios on the Structure and Energy Storage Properties of Strontium Barium Niobate-Based Glass-Ceramics

Strontium barium niobate-based glass-ceramics (BSN-AS) with various Al/Si ratios have been prepared through melt casting followed by controlled crystallization. The effect of the various Al/Si ratios on the phase evolution, microstructure, dielectric properties, and energy storage density, and the relationship between the breakdown strength properties and the activation energy Ea of BSN-AS glass-ceramics, were investigated. The results reveal that the microstructure of BSN-AS glass-ceramics gradually becomes dense and uniform, and the phenomenon of reunited grains is effectively improved in a certain range of Al/Si ratios. With the Al/Si ratios increasing, the breakdown strength increases to a maximum value and then decreases drastically. For the relationship between breakdown strength properties and activation energy Ea, it was found that the various trends between breakdown properties and activation energy Ea of the BSN-AS glass-ceramics are opposite. In this study, the energy storage densities reach 4.8 J/cm3 by adjusting the Al/Si ratios in the BSN-AS glass-ceramics.