Atom permeable gradient-structured hybrid dielectric films for highly improved capacitive energy storage

Nanocomposite dielectrics with heightened energy density exhibit promising prospects for energy storage implementations in contemporary electrical systems. However, high permittivity fillers usually lead to decreased breakdown strength of nanocomposites. Therefore, it is necessary to design the microstructure of nanocomposite dielectrics with balanced breakdown strength and permittivity for achieving optimal energy storage performance. In this work, an inorganic-organic hybrid dielectric materials with gradient permeable structures have been demonstrated though the multi-pulse infiltration (MPI) technology. The hybrid films enriched with TiO₂ can revive the low barrier caused by polymer surface defects and the TiO₂ penetration within the film can provide deep traps for electron capture, thereby enhancing the insulation performance of nanocomposite dielectrics. Additionally, the polar Ti–O bonds and the new ≡ Ti–F bonds can enhance the polarizability of the hybrid material and increase the permittivity. The maximum energy density of hybrid dielectric film in this work reached 21.9 J cm⁻³ at 623 MV m⁻¹ with pretty low inorganic content, which was 97 % higher than that of pure polymer. This study presents an efficient method for creating high-energy-density polymer/ceramic hybrid films for dielectric energy storage applications.