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Effect of K2O addition on glass structure, complex impedance and energy storage density of NaNbO3 based glass-ceramics
摘要： (40-x)Na2O-xK2O-40Nb2O5-20SiO2 (x=0, 5, 10, 15mol%) glass-ceramics are synthesized by traditional melts method. The glass-ceramics are tested by X-ray diffraction (XRD) techniques, and NaNbO3 as major phase led a high permittivity. A microstructure with nanoscale grains enclosed by glass phase is observed by scanning electron microscope (SEM). With the increase of content of K2O, a relaxed glass network structure is obtained, and more kinds of phase are formed. Permittivity comes to 174 approximately when x=5mol%. In addition, the activation energy (Ea) of residual glass phase for Na2O-K2O-Nb2O5-SiO2 glass-ceramics firstly increase then decrease. Breakdown strength (BDS) of all samples increase and then decrease with the increase of content of K2O, and maximum BDS is obtained when x=10mol%. And maximum theoretical energy density is 1.43J/cm3 when x=5mol%.
关键词： breakdown strength,glass network structure,Na2O-K2O-Nb2O5-SiO2 glass-ceramics
更新于2025-11-14 17:28:48
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Robust flower-like ZnO assembled ?2-PVDF/BT hybrid nanocomposite: Excellent energy harvester
摘要： Need of renewable green energy sources due to low cost synthesis, mechanically strong, high energy storage capacity with improved dielectric performance have been receiving much attention. Present work render the ZnO particle and flower-like morphology assemble semicrystalline β phase PVDF/BT nanocomposite, successfully synthesized by spin coating method and characterized by XRD, SEM, EDS and FTIR techniques. Also the energy storage density of composite with modified structure is largely increased with value 0.056 Jcm-3 at 6 MV/m which is 66% higher than virgin β-PVDF and 82% piezoelectric energy harvesting efficiency. Maximum dielectric constant is 1774 at 1 Hz for PVDF-BaTiO3-ZnOf [P-BT-ZnOf] nanocomposite film and maximum breakdown strength of 43 kVcm-1. Electrochemical study reveals that P-BT-ZnOf nanocomposite film manifest better potential material. In terms of mechanical performance, P-BT-ZnOf nanocomposite shows maximum Young modulus of 204 MPa, tensile strength of 28.7 MPa and 23.1% elongation to break. These results provide promising capability to enhance the performance of composites for energy storage application, transducers, sensors, capacitors etc.
关键词： Energy density,Tensile strength,Dielectric constant,Nanocomposites,Breakdown strength
更新于2025-09-23 15:21:01
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Ultrahigh Breakdown Strength and Energy Density in PLZST@ PBSAZM Antiferroelectric Ceramics Based on Core-shell Structure
摘要： A novel core-shell structured Pb0.91La0.06(Zr0.552Sn0.368Ti0.08)O3@PbO–B2O3-SiO2-Al2O3-ZnO-MnO2 (PLZST@PBSAZM) antiferroelectric particles were successfully fabricated via sol-gel method. As expected, the sintering temperature was notably reduced from 1250 oC to 1100 oC with the increasing glass contents. More importantly, the breakdown strengths of PLZST@PBSAZM ceramics were significantly increased from 252 kV/cm to 402 kV/cm. As a result, the energy density was up to 7.4 J/cm3 with 1 wt.% of coating glass content, a 55.3% enhancement over the pure PLZST (4.7 J/cm3). Furthermore, the simulations of electric field distribution provided a powerful evidence that the enhancement of the breakdown strength was induced by the core-shell structure, since the glass coating layer could not only undertake the most of electric field, but also impede the grain growth to achieve the smaller grains, which led to the reduction of electric field intensity on the grain cores.
关键词： Core-shell structured,Antiferroelectric,Breakdown strength,Energy density
更新于2025-09-23 15:19:57
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Thickness-tunable growth of ultra-large, continuous and high-dielectric h-BN thin films
摘要： The outstanding thermal properties, mechanical properties and large optical bandgap of hexagonal boron nitride (h-BN) make it very attractive for various applications in ultrathin 2D microelectronics. However, the synthesis of large lateral size and uniform h-BN thin films with a high breakdown strength still remains a great challenge. Here, we comprehensively investigated the effect of growth conditions on the thickness of h-BN films via low pressure chemical vapor deposition (LPCVD). By optimizing the LPCVD growth parameters with electropolished Cu foils as the deposition substrates and developing customized "enclosure" quartz-boat reactors, we achieved thickness-tunable (1.50–10.30 nm) growth of h-BN thin films with a smooth surface (RMS roughness is 0.26 nm) and an ultra-large area (1.0 cm × 1.0 cm), meanwhile, the as-grown h-BN films exhibited an ultra-high breakdown strength of ~10.0 MV cm?1, which is highly promising for the development of electrically reliable 2D microelectronic devices with an ultrathin feature.
关键词： dielectric breakdown strength,h-BN,thin films,LPCVD,2D microelectronics,hexagonal boron nitride
更新于2025-09-19 17:15:36
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Improved breakdown strength of Poly(vinylidene Fluoride)-based composites by using all ball-milled hexagonal boron nitride sheets without centrifugation
摘要： Hexagonal boron nitride (h-BN) is an ideal candidate to endow ferroelectric polymers with high energy density ((cid:1)(cid:2)) due to its intrinsic high breakdown strength ((cid:3)(cid:4)) of 800 kV/mm. Generally, it is believed that only boron nitride nanosheets (BNNSs) could remarkably improve (cid:3)(cid:4) of composite. Nevertheless, low-yield and time-consuming preparation procedures of BNNSs greatly limits the application of h-BN. To overcome this challenge, in this study, all ball-milled h-BN (B-BN) sheets were entirely used to enhance (cid:3)(cid:4) of poly(vinylidene fluoride) (PVDF) without any further centrifugation. (cid:3)(cid:4) of composites increased as ball-milling time increases at filler content of 8 wt%. Remarkably, PVDF with h-BN ball-milled for 16 h (B16-BN) possesses an impressive (cid:3)(cid:4) value of 506.8 kV/mm, which is 2.86 times that of neat PVDF (272.4 kV/mm) and even 1.33 times higher than that of PVDF/h-BN composites (380.6 kV/mm). (cid:3)(cid:4) of PVDF/B16-BN composites is close to that of PVDF/OH-BNNSs composites at same filler content, suggesting that the centrifugation is not a necessary procedure. Besides, improved dielectric loss, calculated (cid:1)(cid:2), mechanical properties and in-plane thermal conductivity can also be achieved for PVDF/B16-BN composites. These improved properties of PVDF/B16-BN composites indicate that the employment of B16-BN can avoid the weakness of low-yield and time-consuming preparation procedure of BNNSs and broaden its applications in the field of energy storage. Finally, the improved dispersion of OH-BN as well as synergy effect (f) on (cid:3)(cid:4) between OH-BN and OH-BNNSs were discussed to better understand these improved properties of PVDF/B16-BN composites.
关键词： Breakdown strength,No centrifugation,Synergy effect,Hexagonal boron nitride
更新于2025-09-19 17:13:59
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Improvement of dielectric breakdown strength and energy storage performance in Er2O3–modified 0.95Sr0.7Ba0.3Nb2O6-0.05CaTiO3 lead-free ceramics
摘要： In this study, 0.95Sr0.7Ba0.3Nb2O6-0.05CaTiO3-x wt. % Er2O3 ceramics (SBNCTEx; x = 0-5) were synthesized using traditional solid-state method, and we investigated the microstructure, energy storage properties as well as the relationship between dielectric breakdown strength and interfacial polarization. As compared with pure 0.95Sr0.7Ba0.3Nb2O6-0.05CaTiO3 ceramics, the Er2O3 dopants suppressed the grain growth of SBNCTEx, and the doped ones showed the dense microstructure. The secondary phase was found for x ≥ 1 according to the EDS results, and the influence of the secondary phase on relative dielectric breakdown strength has also been studied. The dielectric breakdown strength increased from 18.1kV/mm to 34.4 kV/mm, which is good for energy storage. The energy storage density of 0.28J/cm3 and the energy storage efficiency of 91.4% were obtained in the SBNCTE5 ceramics. The results indicate that SBNCTE ceramics can be used as energy storage capacitors.
关键词： Impedance,Er2O3 addition,Dielectric breakdown strength,Energy storage
更新于2025-09-09 09:28:46
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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald, Germany (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Enhanced Electric Breakdown Strength in an Electron-Optical System
摘要： We describe the results of our work on enhanced electric breakdown strength observed in the plasma-anode bipolar optical system of a plasma-cathode electron gun. This kind of optical system uses a plasma-filled diode in which the acceleration and formation of the electron beam occurs in the double layer between the emission surface of the plasma cathode, stabilized by a fine-grained mesh, and the open surface of the anode plasma. The anode plasma is created by self-contained gas-discharge plasma sources whose original design was based on a plasma thruster with anode layer. The parameters of the plasma source are almost independent of the electron beam parameters, and its use in an electron gun enhances the breakdown strength of the acceleration gap and nearly doubles the electron beam current. The thruster-based plasma optical system (POS) resolves the anode grid problem and opens the way to controllable plasma-filled wide-aperture POS. We show that the POS can be effectively used for large-area electron beam formation.
关键词： breakdown strength,anode layer thruster,plasma optical system
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - High Voltage Electrical Properties of Epoxy / h-BN Microcomposites
摘要： Two high voltage properties – DC conductivity and AC breakdown strength – of epoxy composites filled with 30 wt% of micron sized hexagonal boron nitride (h-BN) are discussed in comparison to neat epoxy. The influence of h-BN upon the field dependence of DC conductivity has been studied up to 18 kV/mm. The addition of h-BN does not lead to a modification of conduction mechanisms: the J-V characteristics show an ohmic behavior at low fields and a space charge limited current (SCLC) at higher fields for both neat epoxy and composite. However, the addition of 30 wt% h-BN reduces the overall electrical conductivity and increases the threshold voltage between ohmic and SCLC regions, leading to a significant modification of electrical conductivity within the field range compared to neat epoxy. AC breakdown strength is enhanced for epoxy – h-BN composites while generally speaking the addition of micro fillers in an epoxy matrix tends to decrease it.
关键词： DC conductivity,electrical conduction mechanisms,epoxy composites,hexagonal boron nitride,AC breakdown strength
更新于2025-09-09 09:28:46