Oxidating Fresh Porous Graphene Networks toward Ultra-Large Graphene Oxide with Electrical Conductivity

摘要

Ultra-large graphene oxide (ULGO) is one of the most important graphenederivates because of its processability in constructing various macrostructureswith unique properties. However, existing oxidation–exfoliation technologiesare limited in the available size range, structure controllability, andpreparation efficiency of ULGO by the slow oxidant diffusion among graphiteinterlayers. Herein, a highly efficient strategy to fabricate ULGO featuring theoxidation of porous graphene networks freshly derived from electrochemicaldelamination, which highlights the significance of not only creation but alsokeeping of the fast diffusion channels for oxidant, is proposed. Consumingonly 40 min and ultralow oxidant dosage (1 wt equiv.), this economical oxidationrealizes high-yield preparation (≈99.5%) of ULGO with record-largeaverage size (188.3 μm) and unusual low-defect structure. Unlike previousreports, free-standing films assembled from the as-prepared ULGO exhibitan unexpected electrical conductivity (305.3 S m~(?1)) alongside record-breakingmechanical properties (21.2 Gpa in Young’s modulus, 392.1 Mpa in tensilestrength). Also, the advantage of ULGO in constructing commercially desirablethick graphene films with high thermal conductivity is demonstrated(≈100 μm, 1576.1±26.7 W m~(?1) K~(?1)). This new strategy based on new findingsin mechanism provides a highly efficient route to enlarge lateral size andexpand physical properties of graphene oxide.