High-temperature energy storage capability of polyetherimide composite incorporated with perovskite quantum dots

Polymer film capacitor with high power density and self-healing feature illustrates potential applications in up-to-date daily electronics and pulse electrical suppliers. In order to fulfil the regulations of electrostatic storage, the energy density and charge-discharge efficiency of polymer dielectrics under high temperature needs to be further enhanced. The suppression of conduction loss is an effective strategy for increasing energy storage efficiency and dielectric reliability. In this work, perovskite quantum dots (QDs) with tailored sizes have been synthesized through thermal injection method, and polyetherimide (PEI) composite with low content of QDs was prepared by solution casting method. Based on the quantum size effect with the intrinsic bandgap, the deep trapping sites for the charge carriers are yielded inside composite bulk, which results in the depression of conduction loss under high temperature. The resultant PEI composite demonstrates the improved energy capacity and dielectric reliability, e.g. energy density of 7.2 J/cm(3) with efficiency of 90% at 350 MV/m achieved in 0.3% PEI composite under 100 degrees C. The difference of trap energy between QDs and PEI contributes to the capture of charge carrier via robust electrostatic interaction. Our work demonstrates that the perovskite quantum dots generate deep trapping sites for space charges, which effectively improves the energy capability of PEI composite and promotes the development of high-temperature film capacitor.