Improving high-temperature energy storage performance of PI dielectric capacitor films through boron nitride interlayer

As an important power storage device, the demand for capacitors for high-temperature applications has gradually increased in recent years. However, drastically degraded energy storage performance due to the critical conduction loss severely restricted the utility of dielectric polymers at high temperatures. Hence, we propose a facile preparation method to suppress the conductivity loss of polyimide (PI) films by inserting boron nitride interlayer. The experimental results and computational simulations indicate that consecutive boron nitride interlayer has better effect on suppressing leakage current density of the entire material compared with uniform dispersed boron nitride nanosheet (BNNS) composite films. The experimental results show that the leakage current density of PI films is reduced by an order of magnitude and a classy energy density of 2.58 J/cm(3) at a charge-discharge efficiency of 90% has been achieved at 150 degrees C, far better than pristine PI (0.75 J/cm(3) of energy density and 65% of efficiency under 275 kV/mm and at 150 degrees C). The method we reported in this work is applicable to a variety of polymer dielectric films produced by solution casting for elevated temperature energy storage application.

Automated summary

This study introduces a facile preparation method to suppress the conductivity loss of polyimide films by inserting boron nitride interlayer, which significantly reduces the leakage current density and improves the energy density.