(Invited) Lithium-Ion Transfer Kinetics through Solid Electrolyte Interphase on Graphite Electrodes

Abstract

For the development of lithium-ion batteries (LIBs) for EV, the internal resistances of LIBs should be required for rapid charge. We have focused on the elucidation of the active sites for lithium-ion intercalation/deintercalation reaction on the graphite negative electrodes. In this study, the influence of the SEI on active sites for lithium-ion intercalation/deintercalation at highly oriented pyrolytic graphite (HOPG) and graphite composite electrode was investigated. We clarified the relation between the standard rate constant (k 0) of [Ru(NH3)6]3+/2+ that is a parameter for edge site of graphite and the interfacial lithium-ion transfer resistance (R ct) in various electrolyte solutions. In plots of k 0 vs. 1/R ct, slopes of straight lines varied with electrolyte solutions. This means that the SEI partly blocked the active site, since the activation energies were not dependent on the SEIs. As a result , we could conclude that the number of the active sites for lithium-ion intercalation/deintercalation strongly depend on the kind of SEIs.