A joint research team from the Korea Institute of Materials Science and Pusan National University has developed a technology capable of analyzing the causes of performance degradation in anion exchange membrane water electrolysis systems in real time during actual operation. By presenting a method that allows for the quantitative analysis of voltage losses in water electrolysis equipment by component, it has become possible to identify the causes of performance degradation occurring during long-term operation in more detail.

The Korea Institute of Materials Science announced that a research team led by Dr. Seungmok Choi of the Energy and Environmental Materials Research Division developed the relevant technology in collaboration with a research team led by Professor Yangdo Kim of Pusan National University. The research results were published online in the international academic journal ACS Energy Letters on March 27.

Water electrolysis is a technology that produces hydrogen by electrolyzing water. Among these, anion exchange membrane water electrolysis has been attracting attention as a next-generation hydrogen production method, but there was a problem where performance deteriorated as the voltage increased during long-term operation. The actual equipment consists of a two-electrode structure, so while changes in overall performance can be verified, there were limitations in distinguishing and analyzing specific causes.

Previously, electrode reactions were analyzed separately using three-electrode methods or half-cell experiments, but it was pointed out that this differed from the actual unit cell operating environment, making it difficult to adequately reflect issues at the commercialization stage. To address this, the research team combined electrochemical impedance spectroscopy data obtained from a unit cell in actual operation with a distributed relaxation time analysis technique and established an analysis system to isolate overvoltage.

By applying this technology, the causes of voltage loss can be analyzed by classifying them into electrode reaction resistance, hydroxide ion transfer resistance, membrane and contact resistance, and mass transfer resistance. The research team explained that they confirmed that performance degradation is the result of a complex interplay of ion transfer and mass transport limitations, in addition to simple electrode degradation. Furthermore, they verified the reproducibility of the analysis results through repeated experiments varying electrolyte concentrations and membrane conditions.

This technology is noteworthy for its ability to distinguish reaction characteristics by electrode in an actual two-electrode-based water electrolysis system without the need for a separate three-electrode device. The research team anticipates that this technology can be utilized in the development of electrode materials, the design of membrane and electrode structures, and the establishment of system operation strategies.