Nanoscale Kirkendall Effect Synthesis of Echinus-like SnO2@SnS2 Nanospheres as High Performance Anode Material for Lithium Ion Batteries

Abstract Crystalline echinus-like SnO 2 @SnS 2 shell-shell-structured nanospheres (SSN) are fabricated by a hydrothermal method based on nanoscale Kirkendall Effect. Single crystal SnS 2 nanorods with length of approximately 50 nm and width of approximately 8-15 nm are arranged regularly on the surface of the nanospheres. When the echinus-like SnO 2 @SnS 2 SSN are used as anode materials for Li-ion batteries, the initial capacity is 1558 mA h g −1 , and the reversible capacity after 100 cycles of the products is 548 mA h g −1 . The SnO 2 @SnS 2 nanocomposites also display excellent rate capability with a reversible capacity of 443.4 mA h g −1 even at the current rate of 5 C. The high electrochemical performance is attributed to the synergistic effect of the hierarchical hollow nanostructure: (1) fast ion diffusion and electron transport at electrode/electrolyte interface, (2) sufficient space to minimize the damage to the electrode caused by the volume expansion of tin-based materials during charge-discharge process. The encouraging experimental results suggest that the novel echinus-like hollow shell-shell structured nanospheres have great potential for practical applications of Li-ion batteries.