PhD student project: Development of a reversible bipolar membrane for a saltwater-based battery

September 13 2017
Position Type
Full Time
Organization Type


With increasing penetration of renewable energy sources for electricity production there is a growing societal need for safe, sustainable and scalable electrical energy storage technologies. Salt water can be used as an energy carrier simply by altering pH and salinity differences between reservoirs. An excess of available electricity can be used to obtain an acid and base from its corresponding salt using a bipolar membrane to split water. When electricity is needed, acid and base are recombined into their corresponding salt again while obtaining electrical work. The energy density stored in such osmotic and pH-gradients outcompetes, by an order of magnitude, pumped hydropower, which is currently the leading technology for large scale electrical energy storage. In combination with the wide applicability (no geographical limitations) and scalability (operational in a range of kW-kWh up to MW-MWh), this innovative technology is attractive for stationary electrical energy storage. It is safer and more sustainable than other battery technologies as it does neither contain toxic chemicals nor scarce elements.

Research challenge

Bipolar membranes (BPMs) are a crucial element in this storage technology. Commercially available BPMs are generally applied for acid/base production, i.e., for water dissociation into protons and hydroxyl ions. In the battery application as proposed in this project, the BPM should also be capable to associate these protons and hydroxyl ions again into water. Proof-of-principle experiments show that current BPMs are capable to be operated in dissociation and association cycles, though there clearly is a need for tailored BPMs to increase the round-trip efficiency and lifetime expectancy of the rechargeable water-based battery.


The PhD project is part of the EU Horizon 2020 granted project BAoBaB (Blue Acid/Base Battery). The following partners are part of the consortium: Wetsus (NL), AquaBattery (NL), CIRCE (E), FujiFilm (NL), University of Palermo (I) and SMEDE (I).

The PhD project will be executed within the Wetsus research theme Blue Energy. The following companies are part of this theme: Alliander (, AquaBattery (, FujiFilm (, Landustrie ( , Magneto Special Anodes ( , A. Hak (, REDstack (

Promotor: Kitty Nijmeijer, Eindhoven University of Technology (Membrane Materials and Processes)

For more information contact: Dr. Michel Saakes (


Wetsus, Leeuwarden, The Netherlands

This job comes from a partnership with Science Magazine and Euraxess

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