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

  • Membrane architecture with ion-conducting channels through swift heavy ion induced graft copolymerization V. Sproll, M. Handl, R. Hiesgen, K.A. Friedrich, T.J. Schmidt, L. Gubler
    J. Mater. Chem. A 5, 24826-24835 (2017)
    DOI: 10.1039/C7TA07323BOG-5421
  • Tackling capacity fading in vanadium flow batteries with amphoteric membranes F. Oldenburg, T.J. Schmidt, L. Gubler
    J. Power Sources 368, 68-72 (2017)
    DOI: 10.1016/j.jpowsour.2017.09.051OG-5421
  • Amphoteric ion-exchange membranes with significantly improved vanadium barrier properties for all-vanadium redox flow batteries O. Nibel, T. Rojek, T.J. Schmidt, L. Gubler
    ChemSusChem 10 (13), 2767-2777 (2017)
    DOI: 10.1002/cssc.201700610OG-5421
  • Polyvinylamine-containing adsorbent by radiation-induced grafting of N-Vinylformamide onto ultrahigh molecular weight polyethylene films and hydrolysis for CO2 capture T. Rojek, L. Gubler, M.M. Nasef, E. Abouzari-Lotf
    Ind. Eng. Chem. Res. 56 (20), 5925-5934 (2017)
    DOI: 10.1021/acs.iecr.7b00862OG-5421
  • Unraveling the interaction mechanism between amidoxime groups and vanadium ions at various pH conditions O. Nibel, M. Bon, M.L. Agiorgousis, T. Laino, L. Gubler, T.J. Schmidt
    J. Phys. Chem. C 121, 6436-6445 (2017)
    DOI: 10.1021/acs.jpcc.6b12540OG-5421
  • Bifunctional ion-conducting polymer electrolyte for the vanadium redox flow battery with high selectivity O. Nibel, T.J. Schmidt, L. Gubler
    J. Electrochem. Soc. 163 (13), A2563-A2570 (2016)
    DOI: 10.1149/2.0441613jesOG-5421
  • Stability and degradation mechanisms of radiation-grafted polymer electrolyte membranes for water electrolysis A. Albert, T. Lochner, T.J. Schmidt, L. Gubler
    ACS Appl. Mater. Interfaces 8 (24), 15297-15306 (2016)
    DOI: 10.1021/acsami.6b03050OG-5421
  • Radiation grafted ion-conducting membranes: The influence of variations in base film nanostructure V. Sproll, G. Nagy, U. Gasser, J.P. Embs, M. Obiols-Rabasa, T.J. Schmidt, L. Gubler, S. Balog
    Macromolecules 49 (11), 4253–4264 (2016)
    DOI: 10.1021/acs.macromol.6b00180OG-5421
  • Fuel electrode carbon corrosion in high temperature polymer electrolyte fuel cells—crucial or irrelevant? T. Engl, L. Gubler, T.J. Schmidt
    Energy Technol. 4 (1), 65-74 (2016)
    DOI: 10.1002/ente.201500354OG-5421
  • Grafting design: a strategy to increase the performance of radiation-grafted membranes V. Sproll, T.J. Schmidt, L. Gubler
    Polym. Int. 65, 174–180 (2016)
    DOI: 10.1002/pi.5041OG-5421
  • Structure–property correlations of ion-containing polymers for fuel cell applications V. Sproll, G. Nagy, U. Gasser, S. Balog, S. Gustavsson, T.J. Schmidt, L. Gubler
    Radiat. Phys. Chem. 118, 120–123 (2016)
    DOI: 10.1016/j.radphyschem.2015.01.036OG-5421
  • Radiation-grafted polymer electrolyte membranes for water electrolysis cells: Evaluation of key membrane properties A. Albert, A.O. Barnett, M.S. Thomassen, T.J. Schmidt, L. Gubler
    ACS Appl. Mater. Interfaces 7, 40, 22203-22212 (2015)
    DOI: 10.1021/acsami.5b04618OG-5421
  • Effects of temperature and catalyst type on chemical degradation of radiation grafted membranes in PEFCs Z. Zhang, Y. Buchmüller, L. Bonorand, A. Wokaun, T.J. Schmidt, L. Gubler
    Fuel Cells 15, 4, 610-618 (2015)
    DOI: 10.1002/fuce.201500019OG-5421
  • From electrochemical interface to interphase (2D->3D) on ionomer membranes Y. Buchmüller, R. Hafner, A. Wokaun, T.J. Schmidt, L. Gubler
    ChemElectroChem 2, 338–342 (2015)
    DOI: 10.1002/celc.201402332OG-5421
  • Think Different! Carbon corrosion mitigation strategy in high temperature PEFC: A rapid aging study T. Engl, L. Gubler, T.J. Schmidt
    J. Electrochem. Soc. 162, 3, F291-F297 (2015)
    DOI: 10.1149/2.0681503jesOG-5421
  • Antioxidants in non-perfluorinated fuel cell membranes: prospects and limitations Y. Buchmüller, Z. Zhang, A. Wokaun, L. Gubler
    RSC Adv. 4, 51911–51915 (2014)
    DOI: 10.1039/c4ra09792kOG-5421
  • Mass spectrometry to quantify and compare the gas barrier properties of radiation grafted membranes and Nafion Z. Zhang. R. Chattot, L. Bonorand, K. Jetsrisuparb, Y. Buchmüller, A. Wokaun, L. Gubler
    J. Membr. Sci. 472, 55–66 (2014).
    DOI: 10.1016/j.memsci.2014.08.020OG-5421
  • Polymer-bound antioxidants in grafted membranes for fuel cells Y. Buchmüller, A. Wokaun, L. Gubler
    J. Mater. Chem. A 2, 5870-5882 (2014).
    DOI: 10.1039/c3ta15321eOG-5421
  • Structure of the aqueous phase and its impact on the conductivity of graft copolymer ionomers at saturation S. Balog, K. Jetsiruparb, U. Gasser, G.G. Scherer, L. Gubler
    Polymer 55, 3026-3036 (2014).
    DOI: 10.1016/j.polymer.2014.05.004OG-5421
  • Shape memory effect in radiation grafted ion exchange membranes D. Henkensmeier, L. Gubler
    J. Mater. Chem. A 2, 9482-9485 (2014).
    DOI: 10.1039/C4TA01467GOG-5421
  • On the positive effect of CO during Start/Stop in high-temperature polymer electrolyte fuel cells T. Engl, J. Käse, L. Gubler, T.J. Schmidt
    ECS Electrochem. Lett. 3 (7), F47-F49 (2014).
    DOI: 10.1149/2.0011407eelOG-5421
  • Polymer design strategies for radiation-grafted fuel cell membranes L. Gubler
    Adv. Energy Mater. 4 (3), 1300827 (2014).
    DOI: 10.1002/aenm.201300827OG-5421
  • Proton conducting membranes prepared by radiation grafting of styrene and various comonomers K. Jetsrisuparb, S. Balog, C. Bas, L. Perrin, A. Wokaun, L. Gubler
    Eur. Polym. J. 53, 75-89 (2014)
    DOI: 10.1016/j.eurpolymj.2014.01.021OG-5421
  • Radiation grafted membranes for fuel cells containing styrene sulfonic
    acid and nitrile comonomers
    K. Jetsrisuparb, H. Ben youcef, A. Wokaun, L. Gubler
    J. Membr. Sci. 450, 28–37 (2014)
    DOI: 10.1016/j.memsci.2013.08.037OG-5421