Confined interfacial water-induced coherent lamellar assembly for highly conductive graphene composite sheets

CNFs-induced interfacial hydration regulation enables highly oriented graphene-sheet assembly. • Free-standing graphene sheets achieve a high Herman’s orientation factor ( f ) of 0.83. • Superior mechanical strength and electrical conductivity are simultaneously realized. • Exceptional mechanical durability enables 91.6% capacitance retention after 10,000 bends. Increasing the mechanical stability and in-plane electrical conductivity of free-standing graphene sheets is a critical step toward the development of next-generation electronic devices. However, macroscopic defects (nanoplatelet folding, structural collapse, and interlayer misalignment) inevitably occur during solution-based assembly, severely compromising the electrical conductivity and mechanical strength. Here, we demonstrate that reconstructing the interfacial hydration environment using cellulose nanofibers (CNFs) provides an effective route to regulate the assembly dynamics of graphene oxide nanosheets. The hydroxyl-rich surfaces of CNFs establish robust interfacial hydration layers through dynamic hydrogen-bonding interactions with both graphene nanosheets and water molecules, which regulate nanosheet assembly while suppressing capillary-induced structural disorder during solvent removal. Consequently, the reduced graphene composite sheets exhibit highly ordered in-plane alignment and interlayer stacking coherence. The resultant sheets achieve an ultrahigh electrical conductivity of 1454.9 S cm −1 , a favorable tensile strength of 738.3 MPa, and excellent mechanical durability, retaining over 91.6% of their initial capacitance after 10,000 bending cycles. This work reveals the pivotal role of interfacial hydration in governing the assembly dynamics of graphene nanosheets and establishes a general framework for constructing highly ordered graphene architectures toward high-performance electronic devices. Download: Download high-res image (193KB) Download: Download full-size image