Effect of the BaO-Na$_2$O-Nb$_2$O$_5$-P$_2$O$_5$ glass addition on microstructure and dielectric properties of BNN ceramics (2312.04667v1)

Abstract: Barium sodium niobate Ba$2$NaNb$_5$O${15}$ (BNN) ceramics with different amounts of BaO-Na$_2$O-Nb$_2$O$_5$-P$_2$O$_5$ (BNNP) glass were prepared via the conventional solid-state method. The effect of glass content on the structural, microstructure, and dielectric properties of BNN ceramics was investigated. The XRD results showed that no secondary phase was formed after adding BNNP glass. It was found that such additions reduce the average grain size and refine the microstructure of the obtained ceramics. Moreover, the samples exhibited a stable dielectric constant over the temperature range of 25$^\circ$C-150$^\circ$C, and their dielectric constants were significantly improved. The ceramic with 7.5 wt% BNNP glass content showed a dielectric constant which is more than twice as much as that of pure BNN ceramic, as well as a low dielectric loss of less than 5%.

• The paper demonstrates that a 7.5 wt% BNNP glass addition doubles the dielectric constant while significantly reducing grain size.
• The study employs conventional solid-state synthesis combined with XRD, SEM, and impedance analysis to evaluate microstructural and dielectric properties.
• The research highlights the potential of BNNP glass for advancing ceramic-based energy storage by improving stability and performance.

Impact of BaO-Na$_2$O-Nb$_2$O$_5$-P$_2$O$_5$ Glass Addition on BNN Ceramics

The paper investigates the effect of BaO-Na$_2$O-Nb$_2$O$_5$-P$_2$O$_5$ (BNNP) glass addition on the microstructure and dielectric properties of Ba$_2$NaNb$_5$O$_{15}$ (BNN) ceramics. Utilizing conventional solid-state synthesis, the authors explore how varying concentrations of BNNP glass influence these ceramics, with a primary focus on dielectric properties crucial for applications in energy storage devices.

Experimental Methods

BNN ceramics were synthesized from BaCO$_3$, Na$_2$CO$_3$, and Nb$_2$O$_5$, while BNNP glass was prepared as per a previous protocol. The mixed powders were compacted and sintered, followed by structural analysis via XRD. Microstructural observations leveraged SEM, and dielectric measurements were performed across a temperature gradient using an impedance analyzer.

Microstructural Analysis

SEM imaging revealed that increased BNNP glass content reduces porosity and grain size in BNN ceramics. Interestingly, glass additions exceeding 7.5 wt% began to degrade the microstructure, suggesting an optimal glass content for maintaining grain boundary clarity and minimizing defect formations. The average grain size decreased significantly from 2.7 μm to 1.7 μm, illustrating effective grain growth inhibition by the glass.

Dielectric Properties

XRD confirmed a stable single phase with a tetragonal tungsten bronze structure throughout the compositions, with no secondary phases detected. Dielectric measurements unveiled a notable enhancement in dielectric constants attributable to the BNNP glass addition. Specifically, a composition with 7.5 wt% BNNP glass showed a dielectric constant more than twice that of pure BNN ceramics. Furthermore, low dielectric loss (<5%) was consistently observed across enhanced temperature ranges.

The dielectric constant displayed strong frequency stability across a broad frequency band, critical for reliable performance in electronic applications. Additionally, low dielectric losses were maintained over various frequencies, which further consolidates the feasibility of these composites in practical energy storage applications.

Implications and Future Work

The paper indicates that BNNP glass is conducive to enhancing the dielectric performance of BNN ceramics, an essential advancement for high-energy density capacitors. These findings have broad implications for fabricating advanced ceramic-based dielectric materials with applications in hybrid electric vehicles and other renewable energy technologies.

Further research should focus on optimizing the glass compositions to balance dielectric constant and breakdown strength maximally. Additionally, evaluating long-term stability under cyclic thermal and electrical stresses could provide deeper insights into practical implementations.

Conclusion

This paper provides a comprehensive analysis of BNN ceramics enhanced by BNNP glass additions. The findings demonstrate significant improvements in dielectric properties and microstructural refinements, offering a promising route for developing high-performance dielectric ceramics. The results warrant further exploration into BNNP glass compositions for enhanced material properties in cutting-edge energy storage technologies.