Energy-storage performance of NaNbO3-based ceramic capacitor derived from a high DOP glass network structure

0.75(0.4Na2O-0.1K2O-0.5Nb2O5)-0.25(0.87SiO2-0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na0.9K0.1NbO3 and NaNbO3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76μm to 1.33μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba2NaNb5O15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm.