Boron Nitride doped Polyimide-based Nanocomposites for High-temperature Capacitive Energy Storage: Challenges and Recommendations

Doping of polyimide-based compounds at high temperature extensively is important for elevated-temperature capacitive energy storage. Polyimide (PI) matrix material can be easily designed for polymer-based dielectric capacitors. By modifying the structure and characteristics of polyimide-based matrix material it can be widespread applicated to high-temperature dielectric capacitive processes using inorganic filler. In the first step of the study, the recent advances were summarized on the enhancement of polyimide-based nanocomposite properties using boron nitride (BN) fillers for high-temperature energy storage. Boron nitride fillers remain promising on improving the dielectric, breakdown strength, thermal conductivity, and thermal stability response of polyimide nanocomposites for high-temperature dielectric capacitors and application. Additionally, the energy storage density and charge discharge efficiency of the boron nitride-reinforced polyimide nanocomposites based on strength and thermal conductivity were investigated. The current challenges, which are associated with the fabrication and characterization of boron nitride-reinforced polyimide nanocomposites for high-temperature energy storage were summarized. In the second step of the study, high-temperature dielectric polymer nanocomposites composed of polyimide with boron nitride nanosheets (BNPN) was generated by taken into consideration the effects of increasing multilayer structure of BNPN on the conduction loss of nanocomposites is effectively reduced. At 150oC, the discharge energy density of the nanocomposite containing six 0.50 mg/l BNPN layers is 5.6 J/cm3, which is higher than that of BNPN with 1.0 mg/l. The experimental results show that the alternating multilayered structure can reduce the conduction loss and leakage current density more effectively. This work provides a feasible idea for the scalable design of high-temperature capacitor dielectrics.