Grain boundary engineering of SiO2-modified Bi(Mg0.5Ti0.5)O3 films toward high-performance capacitive energy storage

To promote the development of pulsed power technology, the challenge of achieving bidirectional optimization in polarization and breakdown behavior has been a critical problem to be solved urgently in current research. Aiming to promote the development and innovation in the field of dielectric energy storage, the grain boundary engineering strategy is proposed in this work and conducted in the ferroelectric Bi(Mg 0.5 Ti 0.5 )O 3 -based films through SiO 2 modification to comprehensively improve the energy storage performance. The introduction of linear dielectric SiO 2 is favorable to enhance the heterogeneity of chemical composition and local structure, thereby effectively regulating the microstructure by suppressing grain growth, which minimizes the leakage current density and polarization hysteresis, leading to an enhancement of E b from 2.13 MV/cm to 3.77 MV/cm. Consequently, a high energy density of 108.3 J/cm 3 together with outstanding stability within a broad temperature/cycle/frequency range is synchronously achieved in Bi(Mg 0.5 Ti 0.5 )O 3 film with 10 mol% SiO 2 addition. This contribution offers novel insights for the design of high-performance dielectric ceramic film materials.