Characterisation of ion transport in sulfonate based ionomer systems containing lithium and quaternary ammonium cations

Yogita Oza, Douglas Robert Macfarlane, Maria Forsyth, Luke A O'Dell

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Two sulfonated ionomers based on poly(triethylmethyl ammonium 2-crylamido-2-methyl-1-propane sulfonic acid) (PAMPS) and containing mixtures of Li+ and quaternary ammonium cations are characterised. The first system contains Li+ and the methyltriethyl ammonium cation (N1222) in a 1:9 molar ratio, and the 7Li NMR line widths showed that the Li+ ions are mobile in this system below the glass transition temperature (105 C) and are therefore decoupled from the polymer segmental motion. The conductivity in this system was measured as 105 S cm1 at 130 C. A second PAMPS system containing Li+ and the dimethylbutylmethoxyethyl ammonium cation (N114(2O1)) in a 2:8 molar ratio showed much lower conductivities despite a significantly lower Tg (60 C), possibly due to associations between the Li+ and the ether group on the ammonium cation, or between the latter cations and the sulfonate groups.
Original languageEnglish
Pages (from-to)80-86
Number of pages7
JournalElectrochimica Acta
Publication statusPublished - 2015


  • polymers
  • electrolytes
  • ionomers
  • NMR
  • conductivity

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