Insight Into Space Charge Suppression by Interfacial Deep Traps in Polymer Nanocomposites

Polymer nanocomposites are attractive for HVDC insulation applications, especially for HVDC cables, due to their ability to suppress space charge accumulation through interfacial effects. However, direct evidence to support the existence of interfacial effects at the nanoscale is still lacking. Therefore, rational design and molecular engineering of the interfaces to improve the insulation properties of polymer nanocomposites remain unavailable. Here, we show that efficient space charge suppression can be achieved in polymer nanocomposites at temperatures up to 100 °C by introducing local deep traps through carefully designed nanoparticle/polymer interfaces. The local interfacial deep traps are directly detected at the nanoscale using intermodulation electrostatic force microscopy (ImEFM). This work provides a deep understanding of the interfacial effects in polymer nanocomposites and will enable the rational design of interfaces for high-performance insulation materials.