Multi-Block Copolymer Membranes Consisting of Sulfonated Poly(p-phenylene) and Naphthalene Containing Poly(arylene Ether Ketone) for Proton Exchange Membrane Water Electrolysis

Glassy hydrocarbon-based membranes are being researched as a replacement for perfluorosulfonic acid (PFSA) membranes in proton exchange membrane water electrolysis (PEMWE). Here, naphthalene containing poly(arylene Ether Ketone) was introduced into the Poly(p-phenylene)-based multi-block copolymers through Ni(0)-catalyzed coupling reaction to enhance pi-pi interactions of the naphthalene units. It is discovered that there is an optimum input ratio of the hydrophilic monomer and NBP oligomer for the multi-block copolymers with high ion exchange capacity (IEC) and polymerization yield. With the optimum input ratio, the naphthalene containing copolymer exhibits good hydrogen gas barrier property, chemical stability, and mechanical toughness, even with its high IEC value over 2.4 meq g(-1). The membrane shows 3.6 times higher proton selectivity to hydrogen gas than Nafion 212. The PEMWE single cells using the membrane performed better (5.5 A cm(-2)) than Nafion 212 (4.75 A cm(-2)) at 1.9 V and 80 degrees C. These findings suggest that naphthalene containing copolymer membranes are a promising replacement for PFSA membranes in PEMWE.

Automated summary

Research has found that introducing naphthalene into poly(arylene ether ketone) multi-block copolymers enhances the pi-pi interactions of the naphthalene units, resulting in high ion exchange capacity and polymerization yield. The naphthalene-containing copolymer membrane exhibits good hydrogen gas barrier property, chemical stability, and mechanical toughness, with a proton selectivity to hydrogen gas 3.6 times higher than Nafion 212. PEMWE single cells using this membrane perform better than Nafion 212, indicating that naphthalene-containing copolymer membranes are a promising replacement for PFSA membranes in PEMWE.