Silicon Nanowires for Anodes of Rechargeable Li Power Cells
TBMG-4916
10/01/2008
- Content
Silicon nanowires have been investigated as alternatives to the graphite heretofore widely used as an anode material in rechargeable lithium-ion power cells. The theoretical specific charge capacity of graphite, corresponding to the maximum Li content (at a composition of LiC6) is 372 mA•hr/g. In contrast, the theoretical specific charge capacity of Si corresponding to the maximum Li content (at a composition of Li4.4Si) is much greater — 4.2 A•hr/g. In previous studies in which thin films of silicon on substrates were investigated for use as high-capacity anodes, it was found that charge capacities faded rapidly in charge/discharge cycling because large changes in volume (as much as 310 percent) associated with insertion and extraction of lithium ions caused cracking and crumbling of the films, as well as delamination of the films from the substrates. The basic idea of the present nanowire approach is to disperse the active anode material into regions having small volumes in order to reduce the sizes of the changes in volume in order to reduce the adverse effects of those changes.
- Citation
- "Silicon Nanowires for Anodes of Rechargeable Li Power Cells," Mobility Engineering, October 1, 2008.