Covalent carbon woven-mesh greatly improve thermal conductivity of polyimide film at low content for battery thermal warning display

Highly thermal conductive polyimide (PI) composites have shown great potential in electronic equipment and thermal management. However, a high content of heat-conducting fillers is frequently needed, leading to the increased costs and decreased mechanical performance that greatly limit the applications. Herein, we design a carbon woven-mesh nano-template by covalent linkage as filler and obtain in-situ polymerized PI composite films at a low loading content of 1wt%-7wt%. Surprisingly, the specific PI composite films showed significantly improved thermal conductivity with a largest increase of 730% and good mechanical performance for future utilization. The enormous improvement of thermal conductivity is attributed to the efficiently interconnected heat-conducting framework via “covalent bridge”. Moreover, the excellent thermal management capability and cycling stability of the fabricated films was proved by thermal warning display device in Li-ion battery heat managemen tapplication.