Silicon-Modified Nanofibers for Advanced Lithium Ion Anodes

Advanced rechargeable battery technology providing higher energy densities and higher specific energies is being sought by the OSD to extend the range and capability of small electronic systems. In this proposal, an anode material is proposed based on carbon nanofiber alloyed with silicon. While many researchers have tested carbon-silicon alloys created through various schemes, these materials suffer always from rapid capacity fade after an initial high capacity. The cause for this rapid diminution in capacity is a large change in volume of the silicon that occurs during charging and discharging, leading to fracture of the material and loss of electrical contact. To overcome this barrier, Applied Sciences has employed a patented process for depositing amorphous silicon onto a carbon nanofiber substrate. Anode materials produced from this combination and tested in a half-cell configuration at General Motors Research Center strongly support achieving anode capacities in excess of 2000 mAh/g with high cycle numbers and charge rates.