ION CONDUCTING POLYMERS FOR ENZYMATIC FUEL CELLS APPLICATION: STRUCTURE AND STABILITY INVESTIGATIONS

Student thesis: Master

Abstract

H2/O2 biofuel cells (BioFCs) and in particular enzymatic fuel cells (EFCs) are promising clean, economic and sustainable energy conversion devices. For their large-scale production a technological breakthrough is however necessary. EFCs are often realized without a separation polymer membrane between the anode and the cathode thus limiting the use of pure gases at the electrodes (to avoid H2/O2 explosive mixtures) and influencing the stability of the enzymatic catalysts. The result is a fuel cell with low performances. Within the framework of the A*Midex project “ENZymatic Ion exchange Membrane Fuel Cells (ENZIM-FC)”, the aim is to introduce an ion conducting membrane into the device to increase its performances, lifetime and reduce its dimension. The ion conducting polymer is chosen among a lot of commercial and non-commercial polymers, avoiding the utilization of perfluorinated polymers (like Nafion®), because of their high price, complex synthesis and post synthesis modification and suspected release of hazardous degradation products for the enzymes. In this work the choice is made among ion conducting functionalized aromatic polymers. Different types of aromatic ion conducting polymers (in particular proton conducting like SPEEK, SPPSU and SPES) were studied exploring the influence of the degree of functionalization and different manufacturing process (different casting solvents, temperatures and procedures) on their peculiar properties. In particular the hydrolytic stability (via water uptake measurements) and conductivity properties (via electrochemical impedance spectroscopy) were investigated in a typical buffer solution utilized in EFCs systems. The mechanical behaviour of each membrane was also studied (via tensile test) to evidentiate the differences between polymers and casting procedures. The final idea of the work is to make a screening between different membranes to find out the best one to be utilized within the A*Midex project for the construction of a highperformance EFC.
Date of AwardSep 2020
Original languageEnglish
Awarding Institution
  • Aix Marseille Universite
  • University of Rome Tor Vergata
  • Wroclaw University of Science and Technology
SponsorsERASMUS MUNDUS SCHOLARSHIP

Keywords

  • fuel cell, hydrogen, biofuel cell, enzymatic fuel cell, microbial fuel cell, PFSA polymers, SAP polymers, membrane, single-chamber, double-chamber, bio(fouling)

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