Synthesis of ultralong MnO/C coaxial nanowires as freestanding anodes for high-performance lithium ion batteries

A facile synthesis strategy is reported for the preparation of a freestanding membrane of ultralong MnO/C coaxial nanowires using a novel in situ interfacial polymerization technique. The MnO/C membrane possesses interconnected porous structures with a nanowire diameter of ca. 100 nm and a length of up to hundreds of micrometers. When used as a freestanding anode for lithium ion batteries, the coaxial MnO/C nanocomposites exhibit a high reversible capacity of 832 mA h g^-1 at a current density of 100 mA g^-1 after 100 cycles, good rate capability and outstanding cycling stability with a specific capacity of 480 mA h g^-1 being retained after 600 cycles at a high current density of 1000 mA g^-1. The uniform carbon coating formed along the ultralong one-dimensional nanostructure surface is the key-enabling factor that not only improves the electrode reaction kinetics, but also renders excellent cycling performance by accommodating the large volume variation of MnO during charge/discharge processes. The superior electrochemical properties suggest that the facile synthesis strategy can be extended to the fabrication of other freestanding films for potential application in energy storage systems.