Rational design of multi-walled carbon nanotube@hollow FeO@C coaxial nanotubes as long-cycle-life lithium ion battery anodes.

In this work, we report a high-performance anode material created by rationally encapsulating multi-walled carbon nanotubes (MWNTs) within hollow FeO nanotubes followed by applying a carbon coating. When tested for lithium storage, as-prepared MWNT@hollow FeO@C coaxial nanotubes present high specific capacity, superior rate performance, and outstanding cycling stability. It is capable of delivering high capacities of 758 mA h g at 500th cycle at 0.2 A g, and 409 mA h g after 1000 cycles at a high rate of 1.5 A g. This excellent performance can be attributed to its unique architecture, which provides high electrical conductivity, offers enough void space for volume accommodation, and mitigates the pulverization of FeO during cycles.