Ba(Zr0.35Ti0.65)O3 (BZT35) relaxor ferroelectric films were fabricated on Pt(111)/Ti/SiO2/Si substrate using radio frequency magnetron sputtering and then annealed at different temperatures under a pure oxygen atmosphere and pressure of 0.1 MPa. The effects of annealing temperature on crystallization, ferroelectric properties, and energy storage properties were studied. The crystallinity and film forming quality were improved by increasing annealing temperature. In addition, oxygen vacancies are effectively inhibited, which is conducive to the film obtaining large saturation polarization intensity and small residual polarization intensity. BZT35 film annealed at 750 °C has high energy storage density and efficiency (Wrec = 55.99 J cm−3 and η = 92.1%). This is mainly due to the high breakdown field strength and polarization difference caused by low oxygen vacancy due to appropriate annealing temperature under pure oxygen atmosphere. The excellent performance of BZT35 indicates that it has a wide application prospect in energy storage.
