Epitaxial growth of branched α-Fe₂O₃/SnO ₂ nano-heterostructures with improved lithium-ion battery performance

We report the synthesis of a novel branched nano-heterostructure composed of SnO₂ nanowire stem and α-Fe₂O₃ nanorod branches by combining a vapour transport deposition and a facile hydrothermal method. The epitaxial relationship between the branch and stem is investigated by high resolution transmission electron microscopy (HRTEM). The SnO₂ nanowire is determined to grow along the [101] direction, enclosed by four side surfaces. The results indicate that distinct crystallographic planes of SnO₂ stem can induce different preferential growth directions of secondary nanorod branches, leading to six-fold symmetry rather than four-fold symmetry. Moreover, as a proof-of-concept demonstration of the function, such α-Fe₂O₃/SnO₂ composite material is used as a lithium-ion batteries (LIBs) anode material. Low initial irreversible loss and high reversible capacity are demonstrated, in comparison to both single components. The synergetic effect exerted by SnO₂ and α-Fe ₂O₃ as well as the unique branched structure are probably responsible for the enhanced performance. A unique six-fold-symmetry branched α-Fe₂O₃/SnO₂ nano-heterostructure composed of SnO₂ nanowire stems and α-Fe₂O ₃ nanorod branches are prepared by combining a vapour transport deposition and a facile hydrothermal method. As a lithium-ion battery material, the composite exhibits low initial irreversible loss and high reversible capacity in comparison to both single components.