Synergistic Effect of i-C3F7CN/CO2 and i-C3F7CN/N2 Mixtures

In order to study the synergistic effect of i-C₃F₇CN mixtures, were carried out the power frequency breakdown experiments on 5%–20% i-C₃F₇CN/CO₂ and i-C₃F₇CN/N₂ mixtures in uniform electric fields with pressures ranging from 0.1 to 0.7 MPa. Based on density functional theory (DFT), the configurations of single molecular and bimolecular complexes were established and optimized using the M06-2X-D3/6-311G(d, p) method. Also, the total energy, interaction energy, and bond energy of the molecules or complexes were obtained using M06-2X-D3/6-311+G(d, p) method. The experimental and computational results show that the power frequency breakdown fields of i-C₃F₇CN/CO₂ and i-C₃F₇CN/N₂ mixtures increase linearly with pressure. In the range of 0.1–0.2 MPa, the synergistic effect of the i-C₃F₇CN mixtures enhances as the i-C₃F₇CN proportion increases, and the synergistic effect of i-C₃F₇CN/CO₂ mixture is more significant than that of i-C₃F₇CN/N₂ mixture. The interaction energy between the complexes of i-C₃F₇CN<inline-formula> <tex-math notation="LaTeX">$\ldots $ </tex-math></inline-formula>CO₂ is −7.36 kJ/mol, which is stronger than −3.09 kJ/mol of the complexes of i-C₃F₇CN<inline-formula> <tex-math notation="LaTeX">$\ldots$ </tex-math></inline-formula>N₂. The results show that there is a correlation between the synergistic effect of i-C₃F₇CN mixtures and the intermolecular interaction of i-C₃F₇CN bimolecular complexes. The synergistic effect of i-C₃F₇CN mixtures can be analyzed by calculating the interaction between i-C₃F₇CN and the molecular structure of buffer gases.