Super Dense LiC2 as a High Capacity Li Intercalation Anode

Abstract

, the super dense high‐pressure phase of lithium‐intercalated graphite, has been tested in a two‐electrode cell vs. Li with an organic electrolyte. A primary capacity of 910 mAh/g per carbon atom was observed during the first deintercalation cycle at constant current, almost three times greater than the ideal 372 mAh/g value for the normal saturated‐phase . also exhibited the desirable characteristic of a low and flat working voltage profile, and most of the Li was removed at ∼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 yielded a reversible capacity close to 372 mAh/g, with Li removed at ∼100 mV. The high initial capacity and near ideal reversible secondary capacity suggests that this material could be useful in rechargeable batteries requiring a very large first deintercalation capacity.