File Name : figure s1.png Caption : voltammograms to determine the solvent windows of solvents at various electrode materials with 1 mm dmfc, 100 mm a), c), f): [nⁿbu₄]cl and b), d), e): [nⁿbu₄][bf₄]. scan swept from -0.5 v vs. dmfc at 50 mv s^-1in the direction indicated by the arrows. ce: pt mesh, re: ag/agcl. a): dcm, b): tft, c): odcb, d): pft, e): cb, f): dce. black: r = 0.25 mm pt we, red: r = 0.25 mm au, blue: r = 1.5 mm glassy carbon. File Name : figure s2.png Caption : solvent dependence of λ_mη for 100 mm [nⁿbu₄][bf₄] at 25°c, with the solvent dielectric constant. File Name : figure s3.png Caption : differential capacitance curves for 100 mm [nⁿbu₄][bf₄] at a r = 0.25 mm pt electrode, scanning in the cathodic direction. black: dcm, red: tft, blue: odcb, green: pft, brown: cb, purple: dce. File Name : figure s4.png Caption : randles-sevčik plots for a) 1 mm dmfc and b) 0.5 mm ccpf₆ collected at a r = 0.25 mm pt we for scan rates between 5-500 mv s^-1. black: dcm, red: tft, blue: odcb, green: pft, brown: cb, purple: dce. File Name : figure s5.png Caption : ir corrected macrodisc cvs for 1 mm dmfc and 0.5 mm ccpf₆ at various electrode materials with 100 mm a), c), f): [nⁿbu₄]cl and b), d), e): [nⁿbu₄][bf₄]. scan swept from -0.3 v vs. dmfc at 50 mv s^-1 in the direction indicated by the arrows. ce: pt mesh, re: ag/agcl. a): dcm, b): tft, c): odcb, d): pft, e): cb, f): dce. black: pt we, red: au, blue: glassy carbon. File Name : figure s6.png Caption : representative mass transport corrected tafel plots for a) 1 mm dmfc and b) 0.5 mm ccpf₆ at a r = 12.5 μm we at 25 °c. black: dcm, red: tft, blue: odcb, green: pft, brown: cb, purple: dce.