Electrochemical intercalation of bis(fluorosulfonyl)amide anions into graphite from aqueous solutions

Graphite intercalation compounds of bis(fluorosulfonyl)amide (FSA-GICs) are electrochemically synthesized in a highly concentrated aqueous solution. While only water decomposition occurs at the graphite electrode in a dilute aqueous solution (1 mol kg−1 NaFSA), redox peaks clearly appear in a highly concentrated aqueous solution (19 mol kg−1 NaFSA). Under the application of a constant current, the electrode potential reaches 1.7 V (vs. Ag/AgCl), which is far beyond the upper limit of the potential window, in 19 mol kg−1 NaFSA aq., and the formation of FSA-GIC is confirmed by X-ray diffraction patterns. Acceptor-type GICs using organic anions are observed for the first time in highly concentrated aqueous solutions of NaFSA. Keywords: Concentrated aqueous solutions, Graphite intercalation compounds, Water decomposition, Potential window