Top-Down Ultrasonication-Assisted Exfoliation for Prebonded Phosphorene-Graphene Heterostructures Enabling Fast Lithiation/Delithiation.

We show a top-down synthesis approach to mass-produce phosphorene-graphene nanosheet composites with superior cycle stability and rate capability. Currently, using exfoliation to achieve two-dimensional (2D) materials is primarily limited to pure crystals. We discover that high-quality nanoscale 2D composite phosphorene-graphene sheets can be directly exfoliated from extremely low-cost bulk three-dimensional (3D) black phosphorus-graphite composites synthesized by mechanical milling while maintaining the chemical bonding and intimate electronic contact between 2D composite layers. The hybrid phosphorene-graphene material delivers high reversible capacities of 2030, 2003, and 1597 mAh/g at high current densities of 2, 4, and 6 A/g, respectively. Quantifying the dimensional electrochemical performance, we show that 2D phosphorene-graphene nanosheets not only have excellent electrochemical kinetics for fast lithium-ion diffusion and storage but also maintain the overall structural robustness of the entire electrode for long-term cyclability. This scalable synthesis paves the way for the practical application of phosphorene-graphene materials in batteries.