Substitution of the Nafion® Ionomer with Hydroxypropyl Methylcellulose for Proton Exchange Membrane Water Electrolyzer

Abstract

The use of green hydrogen as a clean energy carrier has become an essential method of storing renewable energy instead of fossil fuels because of environmental concerns[1,2]. Proton exchange membrane water electrolysis (PEMWE) is one of several methods of producing green hydrogen. A perfluorosulfonic acid ionomer called Nafion® was typically used as a binder in PEMWE for many years. It has excellent chemical stability and high ionic conductivity, but it is expensive and has negative environmental effects [3]. It is therefore necessary to investigate new binders for the anode of PEMWE.In this study, we present a new electrode manufacturing method using hydroxypropyl methylcellulose (HPMC) binder and demonstrate that HPMC binder can be used sufficiently instead of traditional Nafion® ionomer through single-cell evaluation under PEMWE conditions. Although it has the disadvantage of low proton conductivity, HPMC is cost-effective and eco-friendly. In the case of the PEMWE anode, because water moves into the cell, water can take over the role of hydrogen ion transport instead of the HPMC binder. By the electrode’s interfacial stability test, it was discovered that the HPMC electrode’s form was preserved for 24 hours without any peeling. Further, it can be seen that there is no significant difference in PEMWE performance even if an HPMC binder with relatively low ionic conductivity is used. Additionally, it was established that each electrode demonstrated a low degradation (less than 0.3 mV h-1) in the subsequent 72 h durability test. The proposed affordable new binder HPMC can aid the development of a new electrode and a cost-effective PEMWE system.