Unique Lithiation and Delithiation Processes of Nanostructured Metal Silicides

We repot that TiSi2 nanonet exhibits considerable activities in the reversible lithiation and delithiation processes, although bulk sized titanium silicide is known to be inactive when used as an electrode material for lithium ion batteries The,detailed mechanism of this unique process was,studied using., electrochemical techniques including the electrochemical impedance spectroscopy (EIS) method By systematic, characterizations of the Nyquist plot's Ad comparisons with the microstructure examinations, we identified the main reason for the activities as the layered crystal structure that is found stable only In TiSi2 nanotube The layer structure is characterized by the existence of a Si only layer, which exhibits reactivity when exposed to lithium, ions,Control studies where TiSi2 nanowires and TiSi2/Si heteronanostructures were involved, respectively, were performed Similar to bulk TiSi2, TiSi2 nanowires show limited reactivity in lithium ion insertion and deinsertion the EIS characteristics of TiSi2/Si heteronanostructures, on the other hand, are distinctly different form those of TiSi2 nanonets The result supports our proposed TiSi2 nanonet lithiation mechanism This discovery highlights the uniqueness of nanoscale materials and will likely broaden the spectrum of electrode material choices for electrochemical energy storage