Bis(fluorosulfonyl)Amide Anion Transfer at Graphite Electrode

As is well-known, many atoms and molecules can enter into graphite to form graphite intercalation compounds GICs). The application of GICs ranges from lithium-ion batteries to hybrid capacitors. The hybrid capacitor, which utilizes anion intercalation/de-intercalation at graphite positive electrode, can possess higher energy densities than electric double layer capacitors whose capacity is dominated by the amount of cation and anion adsorbed (desorbed) on activated carbons.

 To increase the capacities of hybrid capacitors, it is necessary to increase the amount of anions intercalated into graphite. In other words, low-stage graphite intercalation compounds (GICs) must be formed. For the electrochemical anion intercalation, low-stage GICs are synthesized at higher potential exceeding 4.5 V vs. Li⁺/Li and therefore, oxidative decomposition of electrolyte solutions are not negligible at such high-potential region. Here we report electrochemical intercalation/de-intercalation properties of various anions at graphite electrodes, and show the anion intercalation kinetics.