A new inexpensive method aimed at distinguishing the forms in which Li+ remains irreversibly trapped within composite silicon-based anodes was suggested and tested. It includes a life-cycle test at a fixed degree of lithiation during the initial cycles. The integral capacity values obtained from the test were then correlated with the various chemical species of Li+ present in the electrodes after various cycle numbers in both charged and discharged states. Such a technique may provide a quantitative analytical tool for developing this type of electrode. (C) 2007 Published by Elsevier B.V.