Effect of the Na2O–Nb2O5–P2O5 glass additive on the structure, dielectric and energy storage performances of sodium niobate ceramics

S Benyounoussy,L Bih,F Muñoz,F Rubio-Marcos,A El Bouari

doi:10.1016/j.heliyon.2021.e07113

Abstract

A phosphate glass Na2O–Nb2O5–P2O5 (NPP) is incorporated into NaNbO3 (NN) ceramics to examine its impact on the density, rearrangement of structural units, dielectric and energy storage features of the elaborated composites. The sodium niobate ceramic (NN) is prepared using the solid state process, whereas, the Na2O–Nb2O5–P2O5 (NPP) glasses are produced using the method of conventional melt quenching. The glass (NPP) is added to the ceramic (NN) according to the composition (100-x) NN-xNNP; (x = 0, 2.5, 5, and 7.5 %wt). The developed composites are denoted as NN-Gx where x represents the content of glass in %wt. The appropriate sintering temperature for the glass-ceramic composites was measured based on the density measurements. It was found that with the addition of glass, their density was decreased and their fritting at lower temperatures was enhanced. The obtained SST for all composites is about 900 °C. After the densification stage, Raman spectroscopy, X-ray Diffraction, Granulo-laser analysis, and scanning electron microscopy are examined to study the structural approach and the morphology of sintered NN-Gx composites. The NN-G5 composite was found to have a fine grain microstructure that was uniform. The dielectric features of the composite revealed that at ambient temperature the NN-G5 had the greatest dielectric constant. The energy storage performance of the composite was investigated from the P-E plots and the parameters of energy storage. Based on the obtained results, it was concluded that incorporating up to 5% wt. of NNP glass in sodium niobate ceramics positively affects their dielectric and energy storage performances.

Highlights

Many perovskite structure materials have been used as dielectrical devices to store energy for high-density capacitors
The Na2O–Nb2O5–P2O5 glass was added to the pure NaNbO3 (NN) ceramic, it has positively affected the fritting temperature, microstructure, dielectric, and energy storage features of the NN ceramic
It is found that the NN-G5 composite exhibited a high increase in permittivity and low dielectric losses, less than 0.01, and a high improvement of the recoverable energy density reached 68.4 mJ/cm3 with an efficiency energy of 84.8%

Summary

Introduction

Many perovskite structure materials have been used as dielectrical devices to store energy for high-density capacitors. Sodium niobate ceramic NaNbO3 (NN) is considered one of them owing to their exceptionally large permittivity and their weak dielectric loss [1]. The pure NaNbO3 ceramics produced using the conventional solid-state method exhibit the presence of pores between the grains, as NN grain boundaries generally migrate resulting in the growth of grains. The maximum polarization of these ceramics was very high, and the remnant polarization was quite low. To reduce the pores and improve the NN ceramics total energy storage, it is necessary that these materials' dielectric permittivity must be increased while defects must be minimized. Several researchers have thought of improving these properties by adding oxides or glasses to the NN ceramic in order to produce a composite having a high dielectric constant with low dielectric losses and high energy storage density. The improvement of the energy storage performance of lead-free

Methods

Results

Conclusion