Thermoconductive Graphene Fluoride Cross-Linked Aramid Nanofiber Composite Films with Enhanced Mechanical Flexibility and Flammable Retardancy for Thermal Management in Wearable Electronics

Flexible electronics require thermally conductive materials with excellent mechanical flexibility to dissipate heat and ensure optimal performance. This work reports the development of metallic ionic cross-linked thermally conductive and mechanically flexible films composed of aramid nanofibers (ANFs) and exfoliated graphene fluoride (EGF) nanosheets. EGF was prepared by liquid exfoliation of fluorinated graphite and incorporated into ANF films fabricated by vacuum filtration. Metallic ion (Al3+) treatment was used to improve interfacial interactions between the EGF fillers and ANF matrix. The EGF-reinforced ANF composite films displayed excellent in-plane thermal conductivity up to 19.48 W/mK for the sample with 50 wt % EGF, owing to the high intrinsic thermal conductivity of EGFs and their preferential alignment along the in-plane direction. The composite films also exhibited outstanding mechanical flexibility and durability, with tensile strength >150 MPa even at 50 wt % EGF content, enabled by efficient stress transfer across the EGF-ANF interface. Thermal conductivity was thermally stable up to 200 degrees C. The unique combination of high in-plane thermal conductivity, mechanical flexibility, and thermal stability illustrates the potential of ANF/EGF films for effective thermal management in flexible electronics.