Preparation of uniform Si nanoparticles for high-performance Li-ion battery anodes.

Nanostructured silicon has attracted a great deal of attention as an excellent anode material for Li ion batteries (LIBs). However, the use of Si nanomaterials in LIBs is severely hindered by their preparative methods owing to the high cost, low yield, and harsh synthetic conditions. Herein, we report a new method for the synthesis of uniform Si nanocrystals based on the magnesiothermic reduction of natural attapulgite clay. The obtained Si nanocrystals with a uniform size of ca. 10 nm are coated with polypyrrole (denoted ppy@Si) and show excellent electrochemical performance as anode materials for LIBs. After charging-discharging for 200 cycles at a current density of 0.6 A g(-1), the specific capacity value of the ppy@Si anode is ∼954 mA h g(-1). Because of the abundance of attapulgite, the obtained silicon nanoparticles can be exploited as a practical anode material for high-performance Li-ion batteries.