Polyimide is widely used in the field of turn-to-turn insulating materials such as cable wrapping and transformers due to its excellent insulating properties and high and low temperature resistance. Polyimide in the high-temperature and high-voltage state for a long time is prone to trigger flashover along the surface leading to the destruction of insulation performance

and its surface charge accumulation and dissipation characteristics have an important impact on its insulation damage. MXene is a nano-material consisting of two-dimensional transition metal carbides (nitrides)

with a large specific surface area and a wealth of tunable surface functional groups (—OH

—F and —O)

which have a strong attraction to electrons after oxidation

and can limit the leakage current and improve the electrical strength and resistivity. MXene/PI composite films with different mass fractions were prepared by adding two-dimensional MXene nanosheets to study the effect of the transport behavior of surface charge on the flashover of polyimide composite films at different temperatures. In this paper

we study the trap distribution and flashover law of composite films with different mass fractions of MXene/PI nanocomposites at 25 ℃

50 ℃

and 80 ℃. It is found that the flashover voltage increases and then decreases with the increase of MXene content

in which the flashover voltage of 0.5 wt% MXene/PI composite film is the largest. The flashover voltage increases and then decreases as the temperature rises

and the flashover voltage of MXene/PI composite films with different mass fractions is the overall maximum at 50 ℃. The flashover voltage of MXene/PI composite films with different mass fractions is the overall maximum at 0.5%. Its deep trap energy level and density are maximum when the concentration is 0.5%

and the pattern is similar to the flashover voltage. The addition of a certain amount of 2D nanosheets can effectively change the energy level distribution in the interfacial region

leading to the increase of the deep trap energy level

and the density of the composite material will limit the electron migration

resulting in the increase of its resistivity and the increase of the flashover voltage.