Robust lamellar Fe2O3@SnO2 heterostructure for long cycling and high-rate lithium storage

Abstract

Transition metal oxides (TMOs) have attracted great attention for lithium-ion batteries (LIBs) owing to their high theoretical capacity. Unfortunately, the painful volume expansion and inferior electrical conductivity of TMOs lead to nonreversing structural deterioration, disordered particle agglomeration and sluggish transfer efficiency, which results in low rate performance and poor cycling stability. This work reports a kind of lamellar Fe2O3 @SnO2 heterostructure composite for LIBs by the means of uniform epitaxial growth of the SnO2 nanorods on the lamellar Fe2O3. Due to the “synergistic effect” advantage of the unique heterostructure and two kinds of composition, the lamellar Fe2O3 @SnO2 heterostructure delivers a prominent and impressive capacity (1572.7 mA h∙g−1 at 4 A∙g−1), good rate performance (993.7 mA h∙g−1 at 5 A∙g−1) and stable long-cycle durability (848.4 mA h∙g−1 after 4000 cycles at 4 A∙g−1). The finite element mechanical simulation demonstrates that the stress is concentrated at the gap of SnO2 nanorods by epitaxial growth from the lamellar Fe2O3, the junction of SnO2 nanorods and the lamellar Fe2O3 is safeguarded. Hence, the lamellar Fe2O3 @SnO2 heterostructure has good rate performance in addition to being stable over a long cycling process. Therefore, the present work provides an outstanding method to improve the energy storage performance of metal oxide composites and other types of nanocomposites.