Ultrastrong and Highly Conductive Gradient Graphene/Aramid Nanofiber Composite Films

Graphene–polymer composites often face a trade‐off between mechanical strength and electrical conductivity, limiting their applications in flexible electronics. To address this critical challenge, we developed reduced graphene oxide/aramid nanofiber (rGO/ANF) composite gradient films using a sequential vacuum filtration method. The films feature a three‐layer structure with outer rGO/ANF composite layers and a middle pure rGO layer. By tuning the ANF content in the outer layers, an optimal balance between strength and conductivity for the composite gradient films was achieved. The rGO/ANF‐30 film (30 wt% ANF) exhibits a tensile strength of 169.82 MPa, representing a 240% improvement over pure rGO (50 MPa), while maintaining a high conductivity of 91.38 S/cm, only 29% lower than pure rGO (129.14 S/cm). This performance surpasses most reported rGO/ANF composites. The enhancement is attributed to the synergistic effects of ANF reinforcement and the gradient architecture. This work demonstrates that gradient structural design is an effective strategy to overcome the intrinsic trade‐off in graphene–polymer systems, making these composites promising for flexible electronics, wearable devices, and energy storage applications.