Self-template synthesis of CoFe2O4 nanotubes for high-performance lithium storage

Abstract

CoFe₂O₄ nanotubes are synthesized by thermal annealing the precursor template of core–shell composite nanorods, which are prepared via two-step hydrothermal process. The formation of a core–shell template and the self-template conversion from nanorods into nanotubes are systemically characterized by XRD, SEM, TEM, EDX, and BET techniques. When employed as anode material for lithium-ion batteries, the specific 1D hollow nanostructures can shorten the Li⁺ transport path, increase the contact between the active materials and electrolyte, and buffer the volume changes during electrochemical cycles. Endowed with these structural benefits, CoFe₂O₄ nanotubes display excellent electrochemical performance, such as large and stable reversible capacity (988 mA h g⁻¹ at rate of 100 mA g⁻¹ after 100 cycles and 830 mA h g⁻¹ at 1000 mA g⁻¹ after 200 cycles), superior high-rate capability, and durable cycling life (over 500 cycles at high rate of 1000 mA g⁻¹) as well as good capacity retention (94% after 200 cycles at 1000 mA g⁻¹). Moreover, we believe that the present synthesis strategy may offer a universal approach for preparation of other 1D ternary transition metal oxides as high-performance anode materials.