3D Graphene Nanostructure Composed of Porous Carbon Sheets and Interconnected Nanocages for High-Performance Lithium-Ion Battery Anodes and Lithium-Sulfur Batteries

Three-dimensional (3D) graphene materials are attractive in energy storage, but they mostly have disordered microstructures and suffer from weak strength. Here, inspired by a plant, philodendron hederaceum, a hierarchically structured 3D graphene nanostructure composed of vertically aligned porous graphene nanosheets and interconnected nanocages (denoted as PHG) is designed and prepared by a chemical vapor deposition (CVD) method in a fluidized-bed reactor. Compared to in-plane graphene, the hierarchical pores of PHG facilitate the infiltration of electrolyte and transport of ions as well as improve the charge storage capability. The integrated conductive networks of the graphene nanoarchitecture accelerate the transportation of electrons, and the in situ-formed connections between the units of the nanocages are robust for durable electrochemical properties. When used as anode materials of lithium-ion batteries, the PHG exhibits a reversible capacity of 1560 mAh g(-1) at 0.1 A g(-1), more importantly, high-rate capacities (160 mAh g(-1) at 4 A g(-1)), and stable cycling performance. Moreover, for lithium-sulfur batteries, this hierarchically structured 3D graphene could be loaded with sulfur at a higher mass loading, which delivers high specific capacity (1640 mAh g(-1) at 0.1 C), and maintains stable performance. Considering the structural properties, as-prepared 3D graphene will have a wide range of applications in energy storage.