title: Insights into the reversible oxygen reduction reaction in a series of phosphonium-based ionic liquids.
abstract: New findings supporting the stability of the superoxide ion, O2˙(-), in the presence of the phosphonium cation, [P6,6,6,14](+), are presented. Extended electrochemical investigations of a series of neat phosphonium-based ILs with different anions, including chloride, bis(trifluoromethylsulfonyl)imide and dicyanamide, demonstrate the chemical reversibility of the oxygen reduction process. Quantum chemistry calculations show a short intermolecular distance (r = 3.128 Å) between the superoxide ion and the phosphonium cation. NMR experiments have been performed to assess the degree of long term degradation of [P6,6,6,14](+), in the presence of superoxide and peroxide species, showing no chemically distinct degradation products of importance in reversible air cathodes.
authors.affiliation: ARC Centre of Excellence for Electromaterials Science, IFM-Institute for Frontier Materials, Deakin University, 221 Burwood Hwy, Burwood, Victoria 3125, Australia. cpg@deakin.edu.au.
authors.forename: Cristina
authors.initials: C
authors.lastname: Pozo-Gonzalo
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Howlett
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Hodgson
authors.forename: Louis A
authors.initials: LA
authors.lastname: Madsen
authors.forename: Douglas R
authors.initials: DR
authors.lastname: MacFarlane
authors.forename: Maria
authors.initials: M
authors.lastname: Forsyth