SYNTHESIS OF POLYVINYL ALCOHOL BASED COMPOSITE MEMBRANE FOR FUEL CELLS


Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2008

Thesis Language: Turkish

Student: AYŞE TAŞKIN

Consultant: İRFAN AR

Abstract:

Membrane is the most important and effective component on the performance of Proton Exchange Membrane Fuel Cells (PEMFC). Membrane must have some properties such as high proton conductivity, mechanical stability, ability to withstand the high temperatures, low cost and chemically inert in order to fuel cell operate efficiently. The most widely used membranes are perfluoro sulphonic acid membranes such as Nafion. Proton conductivity of Nafion membranes is 0,1 S/cm. But, it loses its proton conductivity at high temperatures. Therefore, in this work, PVA based composite membranes were synthesized in order to provide that the membrane has high proton conductivity with more robust physical and chemical characteristics. Polyvinyl alcohol based composite membranes were synthesized by using different additives such as SSA/PEG/TiO2. After membranes were synthesized, some characterization tests such as; FT-IR, TGA-DSC, capacity of water uptake, ion exchange capacity (IEC) and electrochemical impedance measurements (EIM) were performed. According to characterization results, SSA-10TiO2 PVA based membranes show better properties. The highest proton conductivity values were obtained for the 20SSA-10TiO2 membranes under the experimental conditions of 25 ºC at 100 % relative humidity. These values are 0,0025 S/cm. Proton conductivity values are decreased, when temperature is increased and 20SSA-10TiO2 membranes proton conductivity is decreased in 0,00032 S/cm at 80°C. In addition to these, IEC of this membrane is found as 9,64 meq/g. The results of the characterization tests show that synthesized membranes can be used in polimer electrolit membrane fuel cells.