Nitrogen doped carbon nanotubes encapsulated MnO nanoparticles derived from metal coordination polymer towards high performance Lithium-ion Battery Anodes

It is still a great challenge to develop the long-life anode active materials for lithium ion batteries (LIBs) due to those issues resulting from the volumetric expansion of electrode materials during lithiation. Herein, we report the preparation of N-doped carbon (N-C) nanotubes encapsulated MnO nanoparticles with the size of 20-50 nm by hydrolysis of metal coordination polymers (MCPs) in nitrogen gas, which is different from typical metal oxide/C core/shell nanostructures with conformal coating. The MnO/N-C nanotubes with an empty space between the nanoparticles allow for more volume expansion, which can effectively overcome existed issues such as MnO dissolution, disintegration, aggregation and volumetric expansion during the lithium ions insertion/extraction. When evaluated as electrode materials for lithium-ion batteries, the MnO/N-C nanotubes exhibit discharge and charge capacities of 1557.5 and 1171.0 mAh g^-1 in the initial cycle at 100 mA g^-1, respectively. And more impressively, the reversible capacity of 450.2 mAh g^-1 is remained after increasing the current density to 5 Ag^-1. Especially, the capacity steadily maintains at 804 mAh g^-1 even after 100 charge-discharge cycles at 1 Ag^-1.