A procedure for specific charge and cycling performance measurements on LiMn2O4 spinels for lithium-ion batteries

A procedure for determining the specific charge and the cycling performance of lithium manganese oxide spinels (LiMn2O4) for rechargeable lithium-ion batteries has been developed. Measurements were made in two-electrode electrochemical test cells with an internal arrangement resembling that of coin cells, with either metallic lithium or a graphite composite counter electrode. Applying the procedure to various LiMn2O4 spinels with different degrees of manganese substitution, Li1+yMn2-yO4 (0.05less than or equal toyless than or equal to0.1), and different surface coatings, we observed an increase of the spinel cycle life with an increasing degree of manganese substitution, at the expense of a small decrease of the specific charge. The influence of the type of counter electrode on the specific charge measurements was examined. Furthermore, we investigated the influence of the temperature, 25 degreesC vs. 55 degreesC, on the specific charge and the cycling performance of the spinels with different degrees of manganese substitution. A survey of the combined effects of the counter electrode and the temperature on the specific charge measurements is given.