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

•The echinus-like SnO2@SnS2 shell–shell-structured nanospheres was prepared through a facile hydrothermal method based on nanoscale Kirkendall effect.•The hierarchical and hollow composite structure has proved itself to be helpful to improve the cycle performance of lithium ion batteries.•Exhibited high capacity of 548 mA h g−1 at a current density of 100 mA g−1 after 100 cycles.•Exhibited excellent rate capability and reversible capacity of 870.5, 733.7, 626.4, 577.7, 551.8 and 443.4 mA h g−1 at the high rate of 0.1, 0.2, 0.5, 1, 2 and 5 C, respectively.

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.