Significantly enhanced energy storage performance of BaTiO3-based amorphous thin films through the synergistic function of variable valence ions

Amorphous thin films have widely study due to the excellent breakdown strength and energy storage efficiency in recent years. However, there still exist enormous challenges for practical application due to relatively low polarization and energy density. Herein, we propose a multi variable valence ions doping strategy to enhance the energy storage performance of BaTiO 3 -based amorphous thin films. The Ba 0.92 Bi 0.08 Ti 1-x (Ni 0.5 Mn 0.5 ) x O 3 (BBTNM) amorphous thin films were fabricated by chemical solution deposition method. In addition, the synergistic effects of variable valence ions (Ni, Mn) on the microstructure, dielectric and energy storage properties of the films were systematically studied. Compared with the undoped Ba 0.92 Bi 0.08 TiO 3 (BBT) film, the polarization and energy storage performance of the BBTNM film have been significantly improved owing to the defect dipoles generated by the incorporation of variable valence ions. Notably,a high discharge energy density of 93.3 J/cm 3 together with energy efficiency of 83 % could be achieved in the x=0.08 film at 7.05 MV/cm. Simultaneously, the film exhibits excellent thermal stability within the range of 20 °C to 160 °C, and still maintains favorable performance after 10 5 cycling. Overall, this work introduces a new approach for designing BaTiO 3 -based thin film materials.