Controllable Synthesis of TiO2@Fe2O3 Core-Shell Nanotube Arrays with Double-Wall Coating as Superb Lithium-Ion Battery Anodes

Abstract

Highlighted by the safe operation and stable performances, titanium oxides (TiO₂) are deemed as promising candidates for next generation lithium-ion batteries (LIBs). However, the pervasively low capacity is casting shadow on desirable electrochemical behaviors and obscuring their practical applications. In this work, we reported a unique template-assisted and two-step atomic layer deposition (ALD) method to achieve TiO₂@Fe₂O₃ core-shell nanotube arrays with hollow interior and double-wall coating. The as-prepared architecture combines both merits of the high specific capacity of Fe₂O₃ and structural stability of TiO₂ backbone. Owing to the nanotubular structural advantages integrating facile strain relaxation as well as rapid ion and electron transport, the TiO₂@Fe₂O₃ nanotube arrays with a high mass loading of Fe₂O₃ attained desirable capacity of ~520 mA h g^-1, exhibiting both good rate capability under uprated current density of 10 A g^-1 and especially enhanced cycle stability (~450 mA h g^-1 after 600 cycles), outclassing most reported TiO₂@metal oxide composites. The results not only provide a new avenue for hybrid core-shell nanotube formation, but also offer an insight for rational design of advanced electrode materials for LIBs.