Novel Lithium Ion Anodes

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Summary Lithium-ion batteries have been the most widely used portable power sources for consumer electronic devices since 1991 because of their high energy density and flexible design. While graphite which provides a theoretical capacity of 372mAh/g is commercially used as anode (negative electrode) materials in Li-ion batteries, tremendous research effect has been conducted to identify intermetallic materials as possible alternative anodes with higher capacity and lower irreversibility. In recent year, several binary lithium alloy systems have been investigated, such as Sn, Si, Al and Sb. However, a very large volume change during charge/discharge resulting in cracking and crumbling of the anode leads to mechanical failure of the electrode, therefore severely limit the cyclability of the electrode.   Investigators have fabricated nanoscale hybrid silicon/carbon nanotubes hetero-structures as a lithium-ion battery anode. The unique hybrid structure of silicon/carbon nanotubes enables the carbon nanotubes to provide the mechanical support to accommodate the huge volume change during cycling, and the facile pathway for electrons and lithium ions transportation while the silicon works as reaction sites with lithium to provide high capacity.