The reversible Li-driven copper extrusion/insertion mechanism in Cu2.33V4O11 electrodes has been investigated and a new ion exchange assisted electrochemical process proposed. Most notably, this process entails a concomitant ion exchange of Cu ions for Li ions during the charging of "LixV4O11 + Cu-0" composite electrodes vs. Li. The electrochemical performance of such cells in terms of capacity retention and power are explained on the basis of a competition for the electrochemically generated Cu ions between ion exchange with Li+ within the Li-V-O host and dissolution into the electrolyte. (C) 2005 The Electrochemical Society.