Browsing by Author "Kerres, Jochen"

Now showing 1 - 3 of 3

Open Access
H+-conducting aromatic multiblock copolymer and blend membranes and their application in PEM electrolysis
(2021) Bender, Johannes; Mayerhöfer, Britta; Trinke, Patrick; Bensmann, Boris; Hanke-Rauschenbach, Richard; Krajinovic, Katica; Thiele, Simon; Kerres, Jochen
As an alternative to common perfluorosulfonic acid-based polyelectrolytes, we present the synthesis and characterization of proton exchange membranes based on two different concepts: (i) Covalently bound multiblock-co-ionomers with a nanophase-separated structure exhibit tunable properties depending on hydrophilic and hydrophobic components’ ratios. Here, the blocks were synthesized individually via step-growth polycondensation from either partially fluorinated or sulfonated aromatic monomers. (ii) Ionically crosslinked blend membranes of partially fluorinated polybenzimidazole and pyridine side-chain-modified polysulfones combine the hydrophilic component’s high proton conductivities with high mechanical stability established by the hydrophobic components. In addition to the polymer synthesis, membrane preparation, and thorough characterization of the obtained materials, hydrogen permeability is determined using linear sweep voltammetry. Furthermore, initial in situ tests in a PEM electrolysis cell show promising cell performance, which can be increased by optimizing electrodes with regard to binders for the respective membrane material.
Open Access
Die protonenleitende Membran - Schlüsselkomponente einer Brennstoffzelle
(2001) Roduner, Emil; Kerres, Jochen
Die Brennstoffzellentechnologie wird wohl eine der Schlüsseltechnologien dieses Jahrhunderts werden, da die Energieausnutzung von Brennstoffzellenaggregaten deutlich höher ist als der Wirkungsgrad von Verbrennungsmotoren. Mögliche Anwendungsfelder von Brennstoffzellen sind sowohl stationäre Einsätze in Blockkraftwerken als auch mobile Anwendungen als Energiequelle in Fahrzeugen wie Personen- und Lastkraftwagen, Bussen oder Schienenfahrzeugen und nicht zuletzt in mobilen Elektronikgeräten wie Funktelefonen oder Laptops.
Open Access
Synthesis and characterization of novel perfluoro aromatic side chain sulfonated PSU ionomers
(2024) Martschin, Philipp; Atanasov, Vladimir; Thiele, Simon; Kerres, Jochen
Polyethersulfone (PSU) as a commercially available polymer offers many different opportunities for functionalization for diverse fields of application, for example, electrophilic substitutions like sulfonation and bromination or nucleophilic reactions such as lithiation. This study presents three different polysulfone derivatives, first functionalized by a lithiation reaction, followed by a reaction with carbonyl compounds containing pentafluorophenyl groups. In the last step, the pentafluorophenyl moieties of the modified PSU were sulfonated by thiolation and subsequent oxidation to sulfonic acid groups. Those novel PSU derivatives were characterized by NMR, DSC, TGA, GPC, and titration. Based on these ionomers, we show the fabrication of pure and acid-base blend membranes with promising proton conductivities. These novel sulfonic acid groups containing materials are potentially promising candidates for membranes or ionomers in electrochemical applications such as proton exchange membrane fuel cells (PEMFCs), proton exchange membrane water electrolysis (PEMWEs), or redox flow batteries (RFBs).