Effect of annealing temperature on energy storage performance of NaNbO3-based thin films under pure oxygen

Using the radio frequency magnetron sputtering process, NaNbO3-based antiferroelectric thin films were obtained on Pt(111)/Ti/SiO2/Si substrates. The effects of annealing temperature on the phase structure, dielectric properties, ferroelectric properties, and energy storage properties of the thin films were studied. As the annealing temperature increased, the crystallinity and film quality of the thin films improved. Moreover, oxygen vacancies were effectively suppressed, which is beneficial for the thin film to obtain a higher dielectric constant, a larger saturation polarization, and a smaller residual polarization intensity. The NaNbO3-based thin film has a higher energy storage density, power density and efficiency (W-rec = 3.6 J/cm(3), P-d =200.8 kW/cm(3), eta = 68.31%) at an annealing temperature of 600 degree celsius. The observed phenomenon could be attributed to higher breakdown field strength and polarization difference resulting from the appropriate annealing temperature and the presence of lower oxygen vacancies under pure oxygen atmosphere. The wonderful property of the NaNbO3-based thin film indicates that it will have the potential to be applied in a wide range of contexts within the sphere of energy storage.