New System to Prevent Reverse-Current in Water Electrolyzer
New System to Prevent Reverse-Current in Water Electrolyzer
  • Reporter Lee Ji-Hwan
  • 승인 2023.03.01 21:15
  • 댓글 0
이 기사를 공유합니다

▲Prof. Yong-Tae Kim (left), Ms. Yoona Kim, Dr. Sang-Mun Jung, and cathodic protection system
▲Prof. Yong-Tae Kim (left), Ms. Yoona Kim, Dr. Sang-Mun Jung, and cathodic protection system

 Baseball is a special sport in the sense that there is a way to directly help the team while sacrificing oneself. As such, sacrifice is necessary when preventing the corrosion of metals. We can use sacrificial metal that is easily oxidized to prevent more important metals from corroding. Metals used in galvanizing processes, such as iron plates in street lamps or home appliances, are representative examples of important metals that need sacrificial metal. A technology that can solve the chronic problems in water electrolysis tanks for clean hydrogen has been proposed lately, drawing attention worldwide.
 A research team led by Professor Yong-Tae Kim of Materials Science and Engineering (MSE), Ms. Yoona Kim and Dr. Sang-Mun Jung revealed the mechanism of reverse-current flow after shut-down, which results in severe electrode degradation.
 A water electrolyzer, composed of alkaline water electrolysis and polymer electrolyte membrane water electrolysis, decomposes water with electricity to obtain hydrogen. Among them, alkaline water electrolysis technology has many advantages as it can be used on a large scale and accounts for more than 60% of devices operating around the world in 2020.
 The main problem with this technology is the reverse-current produced after shut-down of the device. This causes electrode degradation and there have been no known mechanisms or solutions to this problem.
 Prof. Kim's team discovered a mechanism in which nickel (Ni) catalysts are oxidized and performance is degraded under shut-down conditions of the water electrolyzer, and they suggested a solution using a cathodic protection system to prevent metal corrosion. The cathodic protection system has been used in various fields for a long time, and the research team connected a sacrificial anode to a nickel cathode using lead (Pb), zinc (Zn), tin (Sn), and aluminum (Al), which are much more oxidative than a nickel. As a result, the research team confirmed that the catalyst continued to maintain excellent activity under reverse-current conditions. In particular, this technology has drawn attention from academia as a simple and novel solution using the cathodic protection system, known as a classic electrochemical technique.
 Meanwhile, the research results were published through the international journal JACS Au published by the American Chemical Society (ACS). The research was selected for the front cover image of the journal in recognition of its excellence. It was carried out with the support of the National Research Foundation (NRF).