A composite Si-carbon fiber comprising a carbon matrix material with 1-90 wt % silicon embedded therein. The composite carbon fibers are incorporated into electrodes for batteries. The battery can be a lithium ion battery. A method of making an electrode incorporating composite Si-carbon fibers is also disclosed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with government support under contract No. DE-AC05-000R22725 awarded by the U.S. Department of Energy. The government has certain rights in this invention.