Horizontally-oriented barium titanate@polydomine/polyimide nanocomposite films for high-temperature energy storage

High-temperature ceramics polymer dielectric nanocomposite materials have broad application prospects in energy storage. The barium titanate (BT) plays an important role as one of outstanding representative ceramics in the dielectric nanocomposite materials. However, there is little known for the effects of two-dimensional (2D) BT morphology and layout on the properties of high-temperature nanocomposite materials. Hence, 2D scale-like BT ceramic fillers were prepared from layered K_0.8Li_0.27Ti_1.73O₄ crystals as precursors using a combined solid-state and hydrothermal process. 2D scale-like BT@polydopamine (PDA) core-shell nanocomposites were prepared via coating PDA on the BT. BT@PDA/polyimide(PI) nanocomposite films were fabricated by horizontally oriented distribution of BT@PDA in the PI matrix. The BT@PDA/PI nanocomposite films exhibit a high energy density (3.34 J/cm³) and high charge-discharge efficiency (83.68 %) at 150 °C. It is currently the highest energy storage performance in the BT/PI nanocomposite films at 150 °C. The excellent properties are due to preventing upward breakdown of electrical pathways and promoting dispersion and entanglement of the electrical pathway routes. Additionally, strong electrostatic interactions between the different polymer chains (PDA and PI) restricts the movement of space charges. This work demonstrates that introducing horizontally oriented, organically shell-modified and 2D small-sized BT nanoparticles into a PI matrix is an effective method for improving energy storage performance.