Structural and kinetic characterization of lithium intercalation into carbon anodes for secondary lithium batteries

Electrochemical intercalation of lithium into carbons has been studied using mesophase-pitch-based carbon fibers having different heat-treatment temperatures, coke, and graphites as anodes for secondary lithium batteries. The variations in the average layer spacing and the voltage profile for the carbons with intercalation depend on the degree of graphitization. The behavior of the polarization resistance and chemical diffusion coefficient is discussed. The rapid diffusion in the graphitized carbon fiber has been attributed to the radial texture in the cross section. It has been found that the activation energy for the diffusion process decreases by increasing the degree of graphitization.