A family of carboxylic acid group containing fluorene/fluorenon copolymers is disclosed as binders of silicon particles in the fabrication of negative electrodes for use with lithium ion batteries. These binders enable the use of silicon as an electrode material as they significantly improve the cycle-ability of silicon by preventing electrode degradation over time. In particular, these polymers, which become conductive on first charge, bind to the silicon particles of the electrode, are flexible so as to better accommodate the expansion and contraction of the electrode during charge/discharge, and being conductive promote the flow battery current.
STATEMENT OF GOVERNMENTAL SUPPORT
 The invention described and claimed herein was made in part utilizing funds supplied by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The government has certain rights in this invention.