Fluorinated Polyimide Nanocomposite Films Incorporated with Plate-like Bi₄Ti₃O₁₂ Capable of High Breakdown Strength and Electrostatic Energy Density

Inorganic and organic nanocomposite dielectrics capable of high energy storage, fast charge-discharge speed, and high-temperature stability are in high demand for application in advanced electronic devices and electrical power systems. However, a major obstacle is the reasonable design of high-performance fillers that are conducive to the breakdown strength. In this work, inorganic-organic nanocomposite films prepared by blending two-dimensional (2D) plate-like Bi₄Ti₃O₁₂ (BTO) with fluorinated polyimide (FPI) are reported. Benefiting from the 2D plate-like BTO, which acts as a physical barrier during the breakdown process, the resultant FPI nanocomposite films exhibit significantly improved breakdown strength over a wide temperature range. Especially, the 1 wt % BTO/FPI nanocomposite film achieves ultrahigh energy densities of 11.15 J cm^-3 under 719.23 MV m^-1 and 5.72 J cm^-3 under 562.52 MV m^-1 at room temperature and 150 °C, respectively. The performance at 150 °C outperforms most of the reported dielectric nanocomposites. This work offers a valuable insight for the development of dielectric fillers with a high aspect ratio, facilitating the progression of high-performance dielectric polymer nanocomposite films.