High‐temperature resistant polyimide‐based sandwich‐structured dielectric nanocomposite films with enhanced energy density and efficiency

Abstract

Development of advanced dielectric materials with both high‐electric energy density and high‐temperature resistant attributes is highly desirable in modern electronics and electrical systems. Herein, a series of polyimide (PI)‐based sandwich‐structured dielectric nanocomposite films have been attempted to develop the advanced high‐temperature resistant capacitor films, wherein the boron nitride nanosheets/PI nanocomposite acts as the outer layers and the zinc oxide (ZnO)/PI as the middle layer. Benefitting from the merits of both fillers and the unique structure, the resulting nanocomposite films can simultaneously achieve both high‐dielectric constant and high‐breakdown strength, as well as low‐electrical conduction loss, thus leading to improved discharged energy densities (Ue) and charge/discharge efficiency (η) at elevated temperatures. It is found that the sandwich‐structured nanocomposite film with 0.4 vol% ZnO (0.4ZnO/PI‐S) can deliver a maximum Ue of 5.29 J cm−3 at 400 MV m−1 and 150°C, which is about 1.9 times that of the pristine PI film. Moreover, outstanding dielectric stability over 10,000 charge/discharge cycles has been demonstrated in such PI‐based sandwich‐structured nanocomposite films at 150°C and 200 MV m−1. This research may provide a new paradigm to explore polymer nanocomposites having excellent energy storage and efficiency at elevated temperatures.

High-Energy-Storage Dielectric Performance of Sandwich PI-Based Composite over a Wide Temperature Range

“…Figure b shows the FTIR spectra of the films. The characteristic imide absorption peaks of asymmetrical and symmetrical CO stretching, C–N stretching, and CO bending of the imide ring were observed at 1777.44, 1717.16 cm –1 , and 1368.54 and 719.49 cm –1 in all of the films. , And the characteristic peaks of aluminum (432.80, 564.17 cm –1 , α-Al 2 O 3 ) become more pronounced as the volume ratio of alumina increases. , And the content of 1DTiO 2 was low and failed to show the characteristic peak. Figure c shows the T g of all films at around 320 °C, indicating that the addition of alumina and titanium dioxide does not affect the structure of the PI itself.…”

“…The characteristic imide absorption peaks of asymmetrical and symmetrical C�O stretching, C−N stretching, and C�O bending of the imide ring were observed at 1777.44, 1717.16 cm −1 , and 1368.54 and 719.49 cm −1 in all of the films. 26,27 And the characteristic peaks of aluminum (432.80, 564.17 cm −1 , α-Al 2 O 3 ) become more pronounced as the volume ratio of alumina increases. 28,29 And the content of 1DTiO 2 was low and failed to show the characteristic peak.…”

Enhanced High-Temperature Capacitive Performance of a Bilayer-Structured Composite Film Employing a Charge Blocking Layer

“…Figure a illustrates the comparison of U e and η of PI/BNNS film with reported PI dielectric materials, including intrinsic PI, , PI nanocomposites, − all-organic PI composites, ,, multilayer-structured PI composites, , and PI composites containing inorganic layer. ,,− The blue, gray, yellow, purple, and green boxes are used to classify the above materials on the right of Figure a. It is found that the PI/BNNS film achieves the maximum U e when η is greater than 90%, which is far superior to the reported PI-based dielectric materials at different temperatures.…”

Computational Simulation for Breakdown and Energy Storage Performances with Optimization in Polymer Dielectrics

“…The introduction of inorganic fillers into the multilayered structure can further increase the corresponding functional properties, either polarization or insulation, which gives the polymer composite dielectric more microstructure design degrees of freedom. [182][183][184][185] Past state-of-the-art literature has reported that incorporating inorganic fillers with different ε r into the polymer matrix would significantly enhance their polarization or insulation, but the distortion of electric fields will appear in the polymer dielectrics no matter what inorganic filler is chosen because of the difference between the matrix and the filler. This makes the E b of the polymer dielectric decline rapidly.…”