Electrode Behavior of Exfoliated Graphite Cathode for Aluminum Metal Anode Rechargeable Battery

Abstract

In this article, electrode behavior of commercially available exfoliated graphite material, GRAFOIL®, was examined in Lewis acidic AlCl3–1-ethyl-3-methylimidazolium chloride ([C2mim]Cl) ionic liquid electrolytes (AlCl3 molar fraction: >50 mol%). Cyclic voltammograms and chronopotentiograms recorded at the GRAFOIL® electrode strongly suggested that the electrode behavior is very similar to that for the graphite cathode active materials employed for the Al metal anode rechargeable batteries and that the intercalation reaction of the [AlCl4]− into the GRAFOIL® proceeds electrochemically. From XRD data of the [AlCl4]−-intercalated GRAFOIL® obtained, a lot of information was obtained about its crystal structure. Relatively high discharge capacity over 80 mAh g−1 of GRAFOIL® cathode would be due to the formation of graphite intercalation compound with stage 3 structure. The laminate-type Al metal anode–GRAFOIL® cathode rechargeable batteries created based on the obtained knowledge showed a favorable battery performance, if the appropriate charging condition that suppress Cl2 generation was applied.

Keywords

• aluminum
• graphite
• rechargeable battery
• ionic liquid