Tuning energy storage and light transmittance properties in ZrO2-modified Na2O-K2O-Nb2O5-SiO2 glass-ceramics

Crystallization kinetics in ZrO2-modified glass-ceramics, (35-x)Na2O-5K2O-40Nb2O5-20SiO2-xZrO2 (x = 0, 1, 3, 5, 10 mol%), is analyzed by crystallization activation energy Ec and kinetic parameter k. A large kinetic parameter k of 1.657 x 1025 is found for the sample with x = 1, which indicates a high tendency toward crystallization. NaNbO3 is formed as the major phase, and its crystallinity changes significantly by the addition of ZrO2. It is found that the dielectric permittivity and maximum polarization are affected by crystallinity. Large domains are formed, and a relaxation process appears at high frequencies. In addition, the breakdown strength (BDS) is affected by the strong electric field distortion rather than the resistance in this system. Complex impedance analysis shows that resistance decreases with the addition of ZrO2. The electric field distortion of the glass-ceramics is simulated by COMSOL. A low interfacial polarization activation energy Ea of 0.821 eV is achieved by the addition of ZrO2. The maximum pulse power density reaches 90 MW/cc at 350 kV/cm for the sample with x = 10, and the pulse energy density attains 0.91 J/cm3 at 300 kV/cm for the sample with x = 1. Light transmittance is achieved because of the low crystallinity and the disappearance of cristobalite SiO2 in the Na2O-K2O-Nb2O5-SiO2 glass-ceramics.