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 E_c and kinetic parameter k. A large kinetic parameter k of 1.657 × 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 E_a 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.