▎ 摘 要
Graphene has excellent potential as a sulfur host in a lithium-sulfur (Li-S) battery owing to its outstanding electrical conductivity and robust mechanical properties. However, graphene itself cannot effectively confine sulfur and suppress polysulfide diffusion, leading to severely fast capacity decay. Herein, nitrogen-doped tubular/porous carbon channels were implanted on graphene sheets (NTPC-G) via a double-template method, with graphene sheets as the shape-directed agents and NiCo-carbonate hydroxide nanowires as the guides of tubular channels. The resultant one-dimensional hollow tubular carbon and two-dimensional graphene nanosheets were wrapped by nitrogen-doped porous carbon layers to construct the unique three-dimensional sandwich-type architectures. The adopted graphene sheets functioned as conductive networks and robust frameworks; moreover, the nitrogen-doped tubular/porous carbon channels comprising hollow tubular carbon and porous carbon coating layers implanted on graphene frameworks served as the sulfur-confined space and polysulfide reservoirs. On integrating these fascinating benefits into one electrode material, sulfur and NTPC-G composites (S@NTPC-G) delivered high rate capability (563 mA h g(-1) at 6 C) and good cycle stability up to 600 cycles. This rational construction of tubular/porous carbon channels on nanosheet materials with comprehensive advantages could be promising and applicable in rechargeable Li-S batteries and other advanced energy storage devices.