Crystallization, microstructure and energy storage behavior of borate glass–ceramics

The borate glass–ceramics with a great energy storage density were fabricated using the melt-quenching method and then heat-treated technology. The microstructure, dielectric properties, energy storage properties and charge–discharge behavior were discussed. The dielectric constant increases monotonically with the increase of crystallization temperature, but the breakdown strength and energy storage density show a trend of increasing first and then decreasing, which is opposite to the activation energy reflecting the interfacial polarization. When the crystallization temperature is 750 °C, the activation energy reaches the lowest value. The glass–ceramics heated at 750 °C have the high breakdown strength of 1487 kV/cm, the maximum energy density of 9.61 J/cm³ and high energy efficiency of 89%, while the actual discharge density reaches the maximum value of 0.4811 J/cm³ under a voltage applied of 500 kV/cm, which makes the materials suitable for applications in energy storage, especially in high power and pulsed power systems.