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

Crystalline echinus-like SnO2@SnS2 shell-shell-structured nanospheres (SSN) are fabricated by a hydrothermal method based on nanoscale Kirkendall Effect. Single crystal SnS2 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 SnO2@SnS2 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 SnO2@SnS2 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. (C) 2014 Elsevier Ltd. All rights reserved.