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Polyaniline Based Composite Membranes for PEM Fuel Cells: Experiments and Factorial Design
Eisa, Ahmed
Eisa, Ahmed
Description
A Master of Science thesis in Chemical Engineering by Ahmed Eisa entitled, “Polyaniline Based Composite Membranes for PEM Fuel Cells: Experiments and Factorial Design”, submitted in December 2020. Thesis advisor is Dr. Amani Al-Othman and thesis co-advisor is Dr. Mohammad Al-Sayah. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
Higher temperature operation (higher than 100 ºC) in proton exchange membrane fuel cells (PEMFCs) is preferred and has several advantages including enhanced fuel cell kinetics, improved catalysts tolerance for contaminants and recovery of useful heat. However, high temperature operation is not permitted using the conventional Nafion membranes as they dehydrate and their proton conductivity dramatically decreases. In this thesis, novel proton conductors based on polyaniline (PANI), ionic liquids (ILs) and zirconium phosphate (ZrP) were fabricated and proposed for the higher temperature operation in PEMFCs. PANI-IL-ZrP composite membranes were synthesized using polytetrafluoroethylene (PTFE) as support. These composite membranes were evaluated for their proton conductivity. The membrane synthesis results showed a promising proton conductivity of around 0.02 S/cm for PANI/IL/ZrP composite membrane as well as high thermal stability at 180 ºC. The membranes’ performance was assessed by generating theoretical polarization curves. The results demonstrated a promising cell performance with a current density of 0.042 A/cm² at a cell potential of 0.6 V that are comparable to the methanol fuel cell. The membrane parameters that affect the performance of fuel cells at high temperature operation were also studied and optimized using factorial design (FD) modeling approach. The studied parameters were the concentrations of PANI, IL and ZrP in addition to the operating temperature and the IL type. The modelling results showed that the concentration of 1-Hexyl-3-Methylimidazolium Tricyanomethanide (HMT) IL contributes approximately to 50% of the conductivity response. The optimization of parameters performed in this thesis offer an important basis as a rational of high temperature PEMFC design.