Si/TiSi2 Heteronanostructures as high-capacity anode material for li ion batteries.

We synthesized a unique heteronanostructure consisting of two-dimensional TiSi(2) nanonets and particulate Si coating. The high conductivity and the structural integrity of the TiSi(2) nanonet core were proven as great merits to permit reproducible Li(+) insertion and extraction into and from the Si coating. This heteronanostructure was tested as the anode material for Li(+) storage. At a charge/discharge rate of 8400 mA/g, we measured specific capacities >1000 mAh/g. Only an average of 0.1% capacity fade per cycle was observed between the 20th and the 100th cycles. The combined high capacity, long capacity life, and fast charge/discharge rate represent one of the best anode materials that have been reported. The remarkable performance was enabled by the capability to preserve the crystalline TiSi2 core during the charge/discharge process. This achievement demonstrates the potency of this novel heteronanostructure design as an electrode material for energy storage.