Advanced Composite 2D Energy Materials by Simultaneous Anodic and Cathodic Exfoliation

Composite materials based on graphene and other 2D materials are of considerable interest in the fields of catalysis, electronics, and energy conversion and storage because of the unique structural features and electronic properties of each component and the synergetic effects brought about by the compositing. Approaches to the mass production of 2D materials and their composites in a facile and affordable way are urgently needed to enable their implementation in practical applications. Here a novel electro-chemical exfoliation approach to prepare 2D composites is proposed, which combines simultaneous anodic exfoliation of graphite and cathodic exfoliation of other 2D materials (namely MoS2, MnO2, and graphitic carbon nitride). The synthesis is carried out in a single-compartment electrochemical cell to in situ produce functional 2D composite materials. Applications of the as-prepared 2D composites are demonstrated as (i) effective hydrogen evolution catalysts and (ii) supercapacitor electrode materials. The method enables the compositing of semiconductive, or even insulating, 2D materials with conductive graphene in an easy, cheap, ecofriendly, yet efficient way, liberating the intrinsic functions of 2D materials, which are usually hindered by their poor conductivity. The method is believed to be widely applicable to the family of 2D materials.