A high-performance hybrid lithium-ion anode material was developed using coaxially coated Si shells on vertically aligned carbon nanofiber (VACNF) cores. The bush-like VACNFs serve  as conductive cores to effectively interface with Si shells for Li+ storage. The open core-shell nanowire structure allows the Si shells to freely expand/contract in the radial direction during Li+ insertion/extraction. A high specific capacity of 3000-3650 mAh(gSi)-1, comparable to the maximum value of amorphous Si, has been achieved. About 89% of capacity is retained after 100 charge-discharge cycles at C/1 rate. After long cycling, the electrode material becomes even more stable, showing the invariant Li+ storage capacity as the charge-discharge rate is increased by 20 times from C/10 to C/0.5 (or 2C). The ability to obtain high capacity at significantly improved power rates while maintaining the extraordinary cycle stability demonstrates that this novel structure could be a promising anode material for high-performance Li-ion batteries.

High-performance lithium-ion battery anode based on core-shell heterostructure of silicon-coated vertically aligned carbon nanofibers

245th National Meeting (2013)

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