Enhanced dielectric performance of XLPE with Benzophenone-derived voltage stabilizers: correlation between molecular structure and electrical behavior

Cross-linked polyethylene (XLPE) is commonly used as an insulation material for high-voltage direct current (HVDC) cables due to its excellent dielectric strength, low dielectric loss, superior insulating properties, as well as its good thermal stability and mechanical performance. This study introduces benzophenone-based voltage stabilizers—3,3’,4,4’-Benzophenonetetracarboxylic dianhydride (BTDA), 4,4’-Diaminobenzophenone (DABP), and 2-hydroxy-4-prop-2-enyloxybenzophenone (ALOH)—which are incorporated into XLPE to enhance its electrical performance. Experimental results show that XLPE incorporated with DABP exhibited the most significant improvement, achieving a 16.5% increase in DC breakdown strength at 30 ℃ and nearly one order of magnitude reduction in conductivity at 70 ℃ and 40 kV·mm − 1 compared with pure XLPE. Space charge accumulation was also effectively suppressed. These stabilizers mitigate space charge accumulation, enhance conductivity, and maintain stable breakdown strength, especially under elevated temperature conditions, thereby improving the decline in electrical performance of conventional materials in high-temperature environments. Density functional theory (DFT) analysis suggested that the synergistic interaction between electron-withdrawing groups (EWGs) and electron-donating groups (EDGs) in DABP facilitates balanced charge trapping and transport. These results demonstrate that DABP is a promising molecular stabilizer for improving the dielectric reliability of XLPE insulation in HVDC applications.