Membranes and Electrochemical Cells

Our mission is to create innovation in the area of polymer electrolyte materials for electrochemical applications, notably fuel cells, electrolysis cells, lithium batteries, and redox flow cells. We aim to prepare polymers with desired functionalities for the respective application and operating conditions, using commercially available and low-cost materials (base films, monomers and additives) and industrially viable processing techniques. Furthermore, we develop dedicated diagnostic methods to study limitations in cell performance and aging of materials and components.


Our synthetic strategy is based on the preparation and functionalization of polymer films via radiation-induced grafting to obtain membranes containing ionic sites. Activation of the base polymer film can be done using an electron beam (performed externally). For surface grafting, the film is activated in a plasma chamber. Activated films are stored in a fridge at a temperature of -80°C. For the grafting reaction, a wide range of vinyl monomers amenable to radical polymerization can be used, such as styrenes and acrylics. Post-treatment of grafted films may involve various chemical processing steps, such as sulfonation to introduce proton exchange sites.

The laboratory has a wide range of characterization methods for ex situ characterization of starting materials, intermediates and membranes: infrared and Raman spectroscopy for composition analysis, SEM-EDX, XPS, DSC/TGA, tensile testing machine, etc. The conductivity of membranes is measured using ac impedance spectroscopy (in-plane or through-plane). In addition, we have a well-equiped fuel cell test infrastructure with test benches for single cells up to stacks for 30 kW power output. We aim to understand component and cell performance characteristics and limitations thereof, in particular aging phenomena of membranes and electrodes under application-relevant or accelerated test conditions.

Water electrolysis plays a key role in future energy scenarios (power-to-gas). We study materials aspects of polymer electrolyte water electrolyzers with a few to increasing performance and efficiency and investigate mechanican and chemical aging phenomena of key cell components. Two custom-built test benches for cells of 25 cm2 active area can be operated up to a pressure of 20 bar. We can measure impedance spectra and monitor the purity of gases (in particular H2 contamination in O2) continuously.

Research Team

Open Positions

Currently the following positions are open in our group:

Furthermore, we have regular openings for student's projects in different areas: fuel cells, electrolyzers, redox flow cells on topics ranging from materials synthesis and characterization to test system design and implementation.


Project Description Duration Contact

ELYDEG Understanding of degradation signatures in water electrolyzers operated with variable input

Swiss Federal Office of Energy OG-5421
2015-2018 Lorenz Gubler

RFBmem Chemistry and Stability of Grafted Membranes for Redox Flow Batteries

Swiss Federal Office of Energy OG-5421
2016-2019 Lorenz Gubler

NF-Antiox17 Radical attack, antioxidants and polymer repair chemistry in hydrocarbon based fuel cell membranes

Swiss National Science Foundation OG-5421
2018-2021 Lorenz Gubler

ELYTEMP Elevated temperature (90-95°C) polymer electrolyte water electrolysis for reduced cost of hydrogen for energy applications

Swiss Federal Office of Energy OG-5421
2018-2021 Lorenz Gubler

Bridge RFB Functionalized separators enabling a break-through of
redox flow batteries for stationary energy storage

SNF Bridge OG-5421
2018-2020 Lorenz Gubler

Recent Publications

Earlier publications can be found in our literature data base

Link to ORCID account of L. Gubler

  • Scaling the graft length and graft density of irradiation-grafted copolymers G. Nagy, V. Sproll, U. Gasser, T.J. Schmidt, L. Gubler, S. Balog
    Macromol. Chem. Phys. 1800311 (2018)
    DOI: 10.1002/macp.201800311OG-5421
  • Revealing the role of phosphoric acid in all-vanadium redox flow batteries with DFT calculations and in situ analysis F.O. Oldenburg, M. Bon, D. Perego, D. Polino, D. Laino, L. Gubler, T.J. Schmidt
    Phys. Chem. Chem. Phys. 20, 23664-23673 (2018)
    DOI: 10.1039/c8cp04517hOG-5421
  • Polymer electrolyte materials for electrochemical energy devices L. Gubler
    Elsevier Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, ISBN 9780124095472 (2018)
    DOI: 10.1016/B978-0-12-409547-2.14285-4OG-5421
  • Communication — Contribution of catalyst layer proton transport resistance to voltage loss in polymer electrolyte water electrolyzers U. Babic, T.J. Schmidt, L. Gubler
    J. Electrochem. Soc. 165 (15), J3016-J3018 (2018)
    DOI: 10.1149/2.0031815jesOG-5421
  • Prospects for durable hydrocarbon-based fuel cell membranes L. Gubler, T. Nauser, F.D. Coms, Y.-H. Lai, C.S. Gittleman
    J. Electrochem. Soc. 165 (6), F3100-F3103 (2018)
    DOI: 10.1149/2.0131806jesOG-5421
  • Effect of glycidyl methacrylate (GMA) incorporation on water uptake and conductivity of proton exchange membranes V. Sproll, T.J. Schmidt, L. Gubler
    Rad.Phys.Chem. 144, 276-279 (2018)
    DOI: 10.1016/j.radphyschem.2017.08.025OG-5421