A fast formation process for lithium batteries

The formation process presently used in the manufacture of lithium-ion batteries includes the solid electrolyte interface (SEI) growth process and another process for lithium intercalation into carbon. The latter process is both time and energy consuming. This study proposes a new concepts that can shorten the formation time by narrowing the potential range and bypassing the intercalation step during formation. The optimum cut-off voltage is 3.7 V for industrial LiCoO2\C cells, and the formation time is reduced to less than one half of that required in the conventional formation procedure. Cycle performance is not affected significantly because the desired SEI growth is mainly completed in the potential range. These results suggest that the new method is superior to conventional formation. (C) 2004 Elsevier B.V. All rights reserved.