Highly Thermally Conductive Fluorinated Graphene/Aramid Nanofiber Films with Superior Mechanical Properties and Thermostability

Thermally conductive polymer composites (TCPCs) are in urgent demand for thermal management in modern power electronic systems. However, poor mechanical properties and low heat resistance (<200 degrees C) restrict their practical applications. Herein, a mechanically strong and highly thermostable fluorinated graphene/aramid nanofiber (f-G/ANF) film was developed by utilizing one-dimensional (1D) ANFs as reinforced blocks and two-dimensional (2D) f-G as a thermally conductive filler for thermal management. The f-G/ANF film exhibited a superior in-plane thermal conductivity of 10.51 W/(m K) due to the formation of a well-arranged layered structure. The in-plane thermal conductivity remained almost unchanged even at 250 degrees C, demonstrating remarkable thermostability. The f-G/ANF film also possessed excellent tensile strength (>110 MPa) and toughness (>9.9 MJ/m(3)). It was demonstrated that no obvious change was observed for the in-plane thermal conductivity of the f-G/ANF film even after repeated 1000 folding cycles. These desirable properties make it promising for thermal management in various fields, especially where high mechanical performance and temperature stability are strictly required.