Nitrogen-doped graphene ribbon assembled core-sheath MnO@Graphene scrolls as hierarchically ordered 3D porous electrodes for fast and durable lithium storage

Graphene scroll is an emerging 1D tubular form of graphitic carbon that has potential applications in electrochemical energy storage. However, it still remains a challenge to composite graphene scrolls with other nanomaterials for building advanced electrode configuration with fast and durable lithium storage properties. Here, a transition-metal-oxide-based hierarchically ordered 3D porous electrode is designed based on assembling 1D core-sheath MnO@N-doped graphene scrolls with 2D N-doped graphene ribbons. In the resulting architecture, porous MnO nanowires confined in tubular graphene scrolls are mechanically isolated but electronically wellconnected, while the interwoven graphene ribbons offer continuous conductive paths for electron transfer in all directions. Moreover, the elastic graphene scrolls together with enough internal voids are able to accommodate the volume expansion of the enclosed MnO. Because of these merits, the as-built electrode manifests ultrahigh rate capability (349 mAh g−1 at 8.0 A g−1; 205 mAh g−1 at 15.0 A g−1) and robust cycling stability (812 mAh g−1 remaining after 1000 cycles at 2.0 A g−1) and is the most efficient MnO-based anode ever reported for lithium-ion batteries. This unique multidimensional and hierarchically ordered structure design is believed to hold great potential in generalizable synthesis of graphene scrolls composited with oxide nanowires for mutifuctional energy storage.