| 초록 |
Problem related to tremendous volume change of group IVA metal during cycling is the dominant obstacle to apply this material for a high capacity anode in lithium ion battery. We have developed a nanostructured form of group IVA metal, consisting with capped, hollow tubular geometries, that is capable of accommodating large volume changes associated with lithiation. These nanotubular structures (wall thicknesses ~ 30 nm; inner diameters ~60 nm) are formed by deposition on sacrificial nanowire templates, to yield in large scale vertical arrays, optimally suited for use as the anode in lithium ion batteries. For example, Si nanotube array electrode has achieved high initial coulombic efficiencies (i.e. ＞ 85%) and stable capacity-retention (＞80% after 50 cycles). Furthermore, Si nanotubes array can be easily blended with the other group IVA metal having high electron conductivity and ion diffusivity. This newly designed group IVA metal nanotube electrode shows stable cycle performance and high rate capability as well as high energy density. These results collectively demonstrate the extent to which engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability. |
