Green and facile production of high-quality graphene from graphite by the intercalation and decomposition of oxalic acid

Abstract

• A green and environmentally friendly chemical exfoliation method was developed. • Oxalic acid is used for the first time alone for chemical intercalation exfoliation of natural flake graphite. • No water-washing and effluent-treatment are involved during the whole chemical exfoliation process. • The 9-μm-thick-graphene film exhibits excellent electrical conductivity (5.05 × 10 5 S/m) and EMI shielding property (53.9 dB). The environmentally friendly preparation of graphene remains a great challenge. Herein, a novel and green preparation method for graphene has been developed. Graphene sheets were successfully exfoliated from graphite by intercalation and decomposition of oxalic acid for the first time. The whole chemical exfoliation process does not involve any waste liquid disposal, and, more importantly, the decomposed products by oxalic acid are CO 2 and H 2 O, respectively, demonstrating that the exfoliation method is environmentally friendly. The obtained graphene sheets exhibit high-quality and large-size with a yield of about ∼ 100%. The prepared graphene film exhibits excellent electrical conductivity (5.05 × 10 5 S/m) and EMI shielding property (53.9 dB with a thickness of 9.0 μm), suggesting a great prospect for miniaturized electronic devices and flexible wearable applications.