Charge transport in protic ionic liquids: Effect of protonation state in 1-methylimidazolium – acetate/trifluoroacetate mixtures

•Mixtures of 1-methylimidazolium acetate and 1-methylimidazolium trifluoroacetate allow tuning electrolyte properties.•Dielectric relaxation spectroscopy and NMR chemical shifts show that trifluoroacetate results in enhanced protonation, less dynamic correlations, and enhanced conductance.•Diffusion ordered NMR indicates that addition of trifluoroactate can enhance Grotthuss-type charge transport.•Protic and aprotic solvents can enhance and suppress conductivity, respectively.