Structural, electrical, and thermal features of polyimide composites filled with semiconductive MXene sheets

Polymer-based dielectrics are widely applied in the fields of electronics and electrical power systems due to the high breakdown strength, excellent flexibility, and unique self-healing capability. However, the low stored energy density and unsatisfactory heat management of polymer dielectrics hinder the development of polymer-based film capacitors. In this research, artificial composites with improved capacitive energy storage and thermal conductivity are fabricated by blending the two-dimensional semiconductive MXene sheets with a polyimide (PI) matrix. Remarkably, a PI based composite with 1 wt. % MXene sheets increases its dielectric permittivity from approximate to 3.27 to approximate to 3.53 and enhances its discharged energy density from approximate to 1.93 to approximate to 2.38 J/cm(3) while maintaining its low dielectric loss of 80%. Meanwhile, a high in-plane thermal conductivity of 0.418 W m(-1) K-1 is achieved for PI/MXene composites with 5 wt. % MXene. In addition, the distribution of temperature field inside the composites has been investigated by a finite element method. These results represent a strategy in polymer dielectrics to achieve simultaneous high energy density and thermal conductivity, which may also have potential for applications in high temperature environments.