Pozo-Gonzalo Cristina, Howlett Patrick C, Hodgson Jennifer L, Madsen Louis A, MacFarlane Douglas R, Forsyth Maria
ARC Centre of Excellence for Electromaterials Science, IFM-Institute for Frontier Materials, Deakin University, 221 Burwood Hwy, Burwood, Victoria 3125, Australia.
Phys Chem Chem Phys. 2014 Dec 7;16(45):25062-70. doi: 10.1039/c4cp04101a.
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.
