Interactions between disordered carbon and lithium in lithium ion rechargeable batteries

The discharge capacity of ribbonlike carbon film with a disordered structure as an anode exceeds the theoretical capacity of graphite anode. In order to explain the phenomenon, a model for the interactions between disordered carbon and lithium in lithium ion rechargeable batteries has been proposed. The model is based on the assumptions that for the disordered carbon with a small crystallite size, Li species are not only intercalated between graphitic layers but also doped at the edge of the graphitic layers, and in addition even more Li species are doped onto the surface of the crystallite. The model can explain why the discharge capacity of disordered carbon material can go beyond the theoretical capacity of graphite anode from the viewpoint of the structural characteristics of disordered carbon. Based on the model, the most appropriate carbon material for use as an anode in lithium ion rechargeable batteries is suggested.