聚醚酰亚胺纳米复合电介质电导的Meyer-Neldel 补偿特性研究

The demand for energy storage equipment capable of achieving low energy loss at extremely high temperatures is growing in fields such as electric vehicles and aerospace. Therefore, developing high-temperature resistant and high-performance dielectric energy storage materials is urgently needed. Polyetherimide is the top choice for high-temperature-resistant energy storage thin films due to its high breakdown strength and superior thermal stability. Incorporating nanoparticles into polyetherimide is an effective way to further reduce high-temperature loss. As one of the main forms of energy loss, researching the internal mechanism of conductance loss is valuable. PEI/SiO₂ nanocomposite dielectrics with varying doping contents are prepared to clarify the effect of nanoparticle doping on dielectric conductivity. The variable temperature conductivity test results reveal that doped nanoparticles can effectively reduce the conductivity. The space charge limited current model and jump conductance model are used to analyze the variable temperature conductance characteristics of polymer nanocomposite dielectrics. It is evident that the change in doping content does not affect the local state distribution shape in the polymer, indicating that the conductance characteristics of the interface region and substrate in the nanocomposite dielectrics remain consistent. The analysis focuses on the temperature dependence of polymer nanocomposite dielectric conductivity. It has been observed that the temperature dependence adheres to the Arrhenius equation and Meyer-Neldel compensation, suggesting that the traps in nanocomposite dielectrics function in the same way as the polymer matrix. The incorporation of nanoparticles increases the energy level of the local state through a reduction in the compliance of the molecular chain in the interface region, which is depicted in the schematic of the folded-chain fringed micellar grain model. This decreases carrier mobility, manifested as a reduction in dielectric conductivity and energy loss.