DEVELOPMENT OF AROMATIC HYDROCARBON-BASED PROTON EXCHANGE MEMBRANE FOR SOLID ELECTROLYTE IN ELECTROLYSIS CELLS

• Main Author: Maulana, Zakaria
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87469
• Institution: Institut Teknologi Bandung

Proton exchange membranes (PEMs) play a vital role in water electrolysis technology for carbon-free hydrogen production. However, the implementation of proton exchange membrane water electrolysis (PEMWE) technology faces challenges such as the complexity of material synthesis and the high production costs of commercial membranes like Nafion 212. Over the past decades, significant efforts have been made to develop alternative hydrocarbon-based PEM materials, such as sulfonated derivatives of polyether ether ketone (PEEK), polyphenylene oxide (PPO), and polyimide. Nevertheless, the polymer backbones of these materials often contain heteroatoms, such as ether groups, which are prone to degradation due to free radical attack. In contrast, aromatic polymers with pure carbon backbones exhibit superior thermal, chemical, and mechanical stability. This study aims to develop ether-free aromatic hydrocarbon polymers as proton exchange membranes for water electrolysis applications. Sulfonated aromatic hydrocarbon polymers (SPP-PXOY) based on p-terphenyl, o-terphenyl, and 2,2,2-trifluoroacetophenone (TFAp) were successfully synthesized through a combination of direct polymerization and post-sulfonation methods. This approach offers advantages, including a simpler synthesis process conducted at temperature and pressure room, using 75% v/v trifluoromethanesulfonic acid (TFSA) as a catalyst. Oleum was employed as the sulfonating agent to graft sulfonate (SO3H) groups onto the polymer backbone. FTIR analysis revealed the presence of sulfone groups (R-SO2-R') acting as sulfonate bridges, leading to crosslinking in the membrane and reducing swelling upon hydration while maintaining excellent proton conductivity. Commercial membranes, such as Nafion 212, exhibit glass transition temperatures (Tg) up to 80 °C, whereas the SPP-PXOY 06 membrane demonstrated superior thermal stability, reaching up to 350 °C. Proton conductivity at 30 °C was measured at 121 mS cm-1, surpassing the fully hydrated Nafion 212 membrane, which achieved only 104 mS cm-1. Overall, ether-free aromatic hydrocarbon membranes based on terphenyl show significant potential for further development in PEM technology.