Effects of TiO₂ nanoparticles and electrodes surface-modified by low-temperature plasma on impulse breakdown voltage of propylene carbonate

Abstract

Insulating and energy-storage materials, such as propylene carbonate, require high dielectric strength. To improve insulation performance of propylene carbonate, we surface treated a copper electrode with a low-temperature plasma based on liquid nanometer modification technology. Thus, a TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nano-modified liquid was prepared and the surface of the copper electrode was modified by sputtering a TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film. The surface morphologies of the electrode surface before and after modification and the impulse breakdown voltages and space charge distributions of pure and nano-modified propylene carbonate were studied. These results indicate that the TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film deposition on the surface of the copper electrode markedly reduced the surface roughness. Furthermore, after the surface modification, the breakdown voltage of pure propylene carbonate and nano-modified propylene carbonate increased by 9.4 and 14.3%, respectively. We analyzed the effects of the electrode surface modification and nanoparticles on the breakdown voltage of propylene carbonate from the perspective of space charge. The nanoparticles introduced shallow traps, which increased the rate of charge dissipation. Furthermore, surface modification of the electrodes inhibited charge injection into the liquid, which affected the generation and development of streamers in the liquid, thereby further improving the breakdown performance of the propylene carbonate.