Acid-assisted hydration of a membrane electrode assembly to enhance the performance and stability of proton exchange membrane water electrolysis

The membrane electrode assembly (MEA) used in proton exchange membrane water electrolysis (PEMWE) must be conditioned before operation. However, conventional hydration-based conditioning methods are time-consuming and energy-intensive. These methods do not entirely condition the MEA and can induce an uneven stress distribution in the catalyst layer (CL) surface, deteriorating the operational stability. In this study, an efficient acid-assisted conditioning method for MEA is introduced to enhance the performance and stability of PEMWE. Subjecting an MEA to optimized acid-assisted hydration produces a substantially higher current density (by up to 19.9 %) than that of conventional MEA—surpassing the 2025 technical target set by the U.S. Department of Energy of 3.0 A cm−2 at 1.90 V. Acid-assisted hydration minimizes mass transfer losses by improving the proton conductivity and hydrophilicity of the anode CL via modulation of the aggregation state of the ionomer in the CL. The enhanced proton conductivity and hydration of the proton exchange membrane reduces the ohmic loss. The proposed approach also enhances the PEMWE stability, which is attributed to the uniform stress distribution on the CL surface of the acid-conditioned MEA. A short, energy- and cost-efficient, and practical conditioning protocol for PEMWE is provided in this study.