Double-shell SnO2@Fe2O3 hollow spheres as a high-performance anode material for lithium-ion batteries

Abstract

Construction of novel electrode materials is an effective way to enhance the electrochemical performance of lithium ion batteries (LIBs). In this work, double-shell SnO₂@Fe₂O₃ hollow spheres are fabricated through a simple template method. It is revealed that the α-Fe₂O₃ nanorods are heterogeneously assembled on the surfaces of hollow SnO₂ spheres. The double-shell SnO₂@Fe₂O₃ hollow spheres, as an anode material for LIBs, demonstrate excellent lithium storage capacity and cycling stability. Their discharge specific capacity decreases to 464 mA h g⁻¹ for the 46th cycle at a current density of 100 mA g⁻¹, and then increases significantly to 1043 mA h g⁻¹ up to the 190th cycle. Compared with SiO₂@SnO₂ (221 mA h g⁻¹ after 190 cycles) and SnO₂ (336 mA h g⁻¹ after 190 cycles) electrodes, the better electrochemical performance of the SnO₂@Fe₂O₃ electrode is ascribed to its hierarchical hollow urchin-like structure, the SnO₂@Fe₂O₃ heterojunctions and the oxygen vacancies in the α-Fe₂O₃ nanorods. The sea urchin-like heterostructures dramatically inhibit the agglomeration and prevent the volume expansion during the cycling process. This work provides a novel way to construct a promising material with enhanced performance as an anode for LIBs.