Mathematical modeling of high-power-density insertion electrodes for lithium ion batteries

Theoretical calculations are compared with well-controlled experiments conducted on a high-surface area, small diameter lithiated-carbon electrodes. The electrodes are shown to yield very high current densities and exhibit little interfacial kinetics resistance or intercalate diffusion resistance. The mathematical treatment describes quantitatively a wide range of electrochemical experiments. The application of the model to the experimental data is facilitated by the use of a reference electrode. Initial cycling behavior of the high-surface-area electrode is elucidated, including clarification of the first-cycle coulombic inefficiency. Nitrogen absorbtion and scanning electron micrographs are utilized to ascertain the microstructural characteristics that distinguish the active electrode material. An asymptotic analysis is used to indicate when diffusion resistance within host particles is negligible; this fact simplifies model calculations and contributes to our overall understanding of insertion processes associated with host particles of very small dimensions.