| Summary: | The present paper provides a new perspective regarding the influence of anions on the rate of lithium ion insertion into graphite. We compared the properties of a LiFSA and solvent system with those of LiPF6 system containing the same solvent when the ionic conductivity of these systems is comparable, to elucidate that better rate properties of the former system than the latter is well reflected in the lower desolvation resistance (Rdesolv) and its lower activation energy (Eadesolv) of the former. The solvation circumstances around Li+ are similar for both the LiFSA and LiPF6 systems, while a significant interaction between Li+ and an anion is observed only in the former. In addition to the previously proposed hypothesis that the Eadesolv reflects the energy required to desolvate Li+ from the last solvating molecule, the present result points to the necessity of considering the influence of the counter anion. Keywords: Lithium-ion intercalation kinetics, Desolvation process, Coordination state, Graphite electrode/electrolyte interface
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