SUPER DENSE LIC2 AS A HIGH-CAPACITY LI INTERCALATION ANODE

LiC2, the super dense high pressure phase of lithium-intercalated grap hite, has been tested in a two-electrode cell vs. Li with an organic e lectrolyte. A primary capacity of 910 mAh/g per carbon atom was observ ed during the first deintercalation cycle at constant current, almost three times greater than the ideal 372 mAh/g value for the normal satu rated-phase LiC6. LiC2 also exhibited the desirable characteristic of a low and flat working voltage profile, and most of the Li was removed at similar to 18 mV. The first deintercalation cycle also showed weak anomalies which coincide with previously identified phase transitions between high order Li in-plane superlattices. Repeated cycling yielde d a reversible capacity close to 372 mAh/g, with Li removed at similar to 100 mV. The high initial capacity and near ideal reversible second ary capacity suggests that this material could be useful in rechargeab le batteries requiring a very large first deintercalation capacity.