Efforts were made to differentiate the contributions to the so-called "ion transfer" barrier at the electrolyte/graphite junction from two distinct processes: (1) desolvation of Li(+) before it enters graphene interlayer and (2) the subsequent migration of bare Li(+) through the ad hoc interphase. By leveraging a scenario where no substantial interphase was formed on Li(+) intercalation hosts, we were able to quantify the distribution of "ion transfer" activation energy between these two interfacial processes and hence identify the desolvation process of Li(+) as the major energy-consuming step. The result confirmed the earlier belief that the rate-determining step in the charging of a graphitic anode in Li(+) intercalation chemistry relates to the stripping of solvation sheath of Li(+), which is closely interwoven with the interphasial resistance to Li(+) migration.

A homologous series of lithium alkyl mono- and dicarbonate salts was synthesized as model reference compounds for the frequently proposed components constituting the electrolyte/electrode interface in Li-ion batteries. The physicochemical characterization of these reference compounds in the bulk state using thermal analyses and X-ray photoelectron, nuclear magnetic resonance, and Fourier transform infrared spectroscopies establishes a reliable database of comparison for the studies on the surface chemistry of electrodes harvested from Li-ion cells.

To understand the source of thermal stability of LiBOB-based electrolyte in lithium-ion cells as well as its unique ability to stabilize graphitic anodes even in the strongly exfoliating solvent propylene carbonate ͑PC͒, the solid electrolyte interface on graphite formed by LiBOB-based electrolyte was investigated by X-ray photoelectron spectroscopy. Preliminary results show that, due to the BOB anion presence, the content of semicarbonate-like components in the graphite/electrolyte interface increases significantly, as indicated by the conspicuous peak located at 289 eV. These components, believed to originate from the oxalato moiety of the anion, are mainly responsible for the protection of graphitic anodes, either at elevated temperatures or in the presence of PC.