Cost-Effective Electrode Fabrication Method Using Hydroxypropyl Methylcellulose Binder for Proton Exchange Membrane Water Electrolysis

Abstract

This study explores improving proton exchange membrane water electrolysis (PEMWE) by achieving both cost-effectiveness and enhanced efficiency through the replacement of the costly and environmentally challenging Nafion ionomer with hydroxypropyl methylcellulose (HPMC) as an anode binder. HPMC, an eco-friendly and cost-effective material, was cross-linked with citric acid to form a durable hydrogel that enhances water and proton transport within the catalyst layer. Using the cross-linked HPMC binder allowed a reduction in cost to 1/54 compared to Nafion ionomer, while the performance of the cross-linked HPMC electrodes remained comparable to Nafion electrodes. After investigating with varying temperatures to determine the appropriate cross-linking temperature, it is suggested that 140 °C was the most suitable. The cross-linked HPMC demonstrated superior hydrophilicity and ionic conductivity compared to the Nafion ionomer, demonstrating its potential as a viable alternative. Initial performance in the single cell revealed that the HPMC-based anode outperformed the Nafion-based anode, with a voltage of 1.782 V vs 1.796 V at 2 A/cm². However, despite this improved initial performance, the higher voltage decay rate of the HPMC binder (0.305 mV/h vs 0.250 mV/h) over 200 h indicates the need for further elaboration on its long-term durability. These findings suggest that the cross-linked HPMC holds promise as a cost-effective and efficient binder for PEMWE anodes, with the potential for further optimization for durability.