New High Conductivity Membranes for Alkaline Electrolyzers

This talk will describe the properties of a new DX series of high conductivity membranes for alkaline electrolyzers.  These membranes were originally developed for use in alkaline carbon dioxide electrolyzers and have recently been tested in alkaline water electrolyzers.   Table 1 compares the membrane conductivity of these membranes to others.  Notice that the conductivity is higher than many of the other membranes that have been used in alkaline electrolyzers. 

Table 1 A comparison of the conductivity of the new membranes to a selection of previously published membranes

Membrane             Conductivity

Tokuyama A201    0.04 S/cm at 24 °C¹

Selemion AMV      0.005 S/cm at 24 °C²

qPVB/Cl                0.016 S/cm at 25 °C³

QA-ETFE               0.03 S/cm at 24 °C⁴

DX4-13                 0.07 S/cm at 24 °C

We have tested the membranes in both alkaline CO₂ and alkaline H₂O elecctrolyzers.  Results are shown in Tables 2 and 3.  Notice that the performance is quite good. 

Table 2  Performance of a variety of membranes in an alkaline CO₂ electrolyzer at room temperature.  All of the results were measured with a ruthenium oxide anode catalyst and a silver cathode catalyst under identical conditions.

Membrane             CO current

Nafion                   0 ma/cm2

Neosepta                8 mA/cm2

AMI-7001 (qPVB/Cl)              3.5 mA/cm2

DX4-13                 110 mA/cm2

DX5-13                 270 mA/cm2

Table 3 Performance of a variety of membranes in an alkaline water electrolyzer  near room temperature

Selemion AMV      90 mA/cm² at 2V at 30 °C²

qPVB/Cl                50 mA/cm² at 2V at 25 °C³

QA-ETFE               120 mA/cm² at 2V at 25 °C⁴

DX4-13                 400 mA/cm2 at 23 °C

These and other results will be discussed. 

References

1.            Duan, Q., S. Ge, and C.-Y. Wang, Water Uptake, Ionic Conductivity and Swelling Properties of Anion-Exchange Membrane. Journal of Power Sources, 2013. 243(0): p. 773-778.

2.            Seetharaman, S., R. Balaji, K. Ramya, K.S. Dhathathreyan, and M. Velan, Graphene Oxide Modified Non-Noble Metal Electrode for Alkaline Anion Exchange Membrane Water Electrolyzers. International Journal of Hydrogen Energy, 2013. 38(35): p. 14934-14942.

3.            Cao, Y.-C., X. Wu, and K. Scott, A Quaternary Ammonium Grafted Poly Vinyl Benzyl Chloride Membrane for Alkaline Anion Exchange Membrane Water Electrolysers with No-Noble-Metal Catalysts. International Journal of Hydrogen Energy, 2012. 37(12): p. 9524-9528.

4.            Wu, X. and K. Scott, A Polymethacrylate-Based Quaternary Ammonium Oh− Ionomer Binder for Non-Precious Metal Alkaline Anion Exchange Membrane Water Electrolysers. Journal of Power Sources, 2012. 214(0): p. 124-129.