Nanoengineered three-dimensional hybrid Fe2O3@PPy nanotube arrays with enhanced electrochemical performances as lithium–ion anodes

In order to optimize the electrode system of lithium–ion batteries (LIBs) for problems like lithium-ion diffusion, electron transport, and large volume change during cycling processes, a novel three-dimensional (3D) hybrid Fe 2 O 3 nanotube array anode coated by polypyrrole (Fe 2 O 3 @PPy) is synthesized via a sacrificial template-accelerated hydrolysis method followed by a chemical vapor-phase polymerization process. In the hollow core–shell nanostructures, the conducting PPy layer could not only facilitate the electron transport, but also force the core to expand inward into the hollow space, which allows for free volume expansion of the Fe 2 O 3 without mechanical breaking. Besides, the static outer surface is contributed to form a stable solid electrolyte interface film. As a result, the integration of 3D hybrid nanostructure electrode is capable of retaining a high capacity of 665 mA h g −1 after 150 cycles with a coulombic efficiency of above 97 %, revealing better cycling properties compared with bare Fe 2 O 3 nanotube arrays’ anode. This nanoengineering strategy is proven to be an ideal candidate for the development of high-performance anode for LIBs.