Bidirectionally High‐Thermally Conductive Graphite Films Derived from Aramid for Thermal Management in Electronics

Abstract As the electronics industry advances toward enhanced performance and miniaturization, the high heat flux generated poses significant challenges for maintaining operational stability. Carbon‐based thermally conductive films, including those derived from graphite, graphene, and polyimide, have shown notable in‐plane thermal conductivity ( K _in ), making them increasingly valuable for electronic heat dissipation. However, their cross‐plane thermal conductivity ( K _out ) remains suboptimal, typically not exceeding 8 W m ⁻¹ K ⁻¹ , which limits their overall heat transfer efficiency under elevated heat flux density. Herein, an innovative approach to fabricate aramid‐derived graphite films (AGFs) characterized by minimal defects, large grain sizes, and well‐ordered stacking through the graphitization of aramid films (AFs) is proposed. Notably, after thermal annealing at 3000 °C, the AGFs exhibit impressive bidirectional thermal conductivity, achieving a K _in of up to 1754 W m ⁻¹ K ⁻¹ and a K _out of 14.2 W m ⁻¹ K ⁻¹ . High‐performance AGFs demonstrate exceptional cooling efficiency in simulated smartphone thermal management scenarios, facilitating rapid heat transfer crucial for the thermal management of high‐power semiconductor chips. This work contributes critical insights into the synthesis of high‐quality graphite films from AFs and offers guidance for the design of bidirectionally thermally conductive graphite films tailored for effective electronic thermal management.