Cu3Si@Si core-shell nanoparticles synthesized using a solid-state reaction and their performance as anode materials for lithium ion batteries.

Cu3Si@Si core–shell nanoparticles with a Si shell coated over the Cu3Si core are synthesized by a solid-state reaction between CuCl and Si. The evaluation process of the core–shell structure shows a mechanism analogous to the Kirkendall effect. As anode materials for lithium ion batteries, Cu3Si@Si core–shell nanoparticles retained a capacity of 903.6 mA h g−1 at the current density of 2 A g−1 over 400 cycles.