3D Hierarchical Anode Configuration Composed of Ultralong N-Doped Graphene Scrolls-Wrapped MnO Nanowires for High-Performance Li-Ion Batteries

Abstract

Transition metal oxides (TMOs) have been touted as one of the most promising anode materials for next generation lithium ion batteries (LIBs). Yet, how to build energetic TMOs-based electrode architectures by addressing the structural and interfacial stability issues facing TMOs anodes still remains a big challenge. Here, we design and fabricate a novel 3D hierarchical anode configuration composed of ultralong porous MnO nanowires (NWs) wrapped within nitrogen-doped graphene scrolls (GSC) which themselves interlinked and embedded in continuous interconnected networks of nitrogen-doped graphene ribbons (GR). Such a hybrid material (namely, MnO@N-GSC/GR) with plenty of internal void space is totally in an ordered 3D hierarchical porous architecture by taking the advantage of multi-scale and multi-dimensional integration of nanoscaled MnO and graphene building blocks, which can address all the issues related to MnO dissolution, conversion, aggregation and volumetric expansion during the Li+ insertion/extraction. As a result, the 3D hierarchical MnO@N-GSC/GR serves high-performance anode materials for LIBs with a very high reversible specific capacity (as high as 765 mAh g-1 at even 1000 mA g-1) and ultrafast rate capability (349 and 201 mAh g-1 at 8000 and 15000 mA g-1, respectively), as well as excellent discharge and charge capabilities (rapidly charged to 86.7% and 79.9% in 10.5 and 4.6 min, respectively, using the constant current mode). Most importantly, such the robust MnO@N-GSC/GR electrode shows no capacity fading even after 1000 cycles at a high current density of 2000 mA g-1, and no morphology change. The as-built 3D hierarchical MnO@N-GSC/GR is the most efficient MnO-based anode materials ever reported for LIBs.