With the rapid development of the Internet of Things and 5G technology, triboelectric nanogenerator, as an emerging technology for self-powered energy, is receiving more attention. Based on previous work, the output of triboelectric nanogenerator has been increased to a significant degree. However, due to the high charge density on the surface of the friction layer, air breakdown occurs all the time and is difficult to control well. Here, a method for suppressing air breakdown phenomenon for contact-separation mode TENG in an $\mathbf{SF}_{\mathbf{6}}$ gas environment is proposed. In the $\text{SF}_{6}$ gas environment, the transferred charge density of the TENG increased from 155.6 $\mu \mathrm{C}/\mathrm{m}^{2}$ to 255.6 $\mu \mathrm{C}/\mathrm{m}^{2},$ which achieved a 64.3% improvement. The method proposed in this paper can significantly increase the output power of triboelectric nanogenerator, which is of great importance to promote the practical application of triboelectric nanogenerator.