A technology capable of suppressing corrosion in the carbon current collector of seawater batteries has been developed, and improvements in seawater battery performance are expected in the future.

Professor Lee Dong-wook of the Department of Energy and Chemical Engineering at UNIST (President Lee Yong-hoon) has developed a technology that significantly enhances the performance of seawater batteries by coating the surface of titanium (Ti), used as a current collector in seawater batteries, with a black suit called titanium carbide (TiC).

In particular, it was discovered that the corrosion of the carbon current collector was suppressed during this process. Systematically analyzing this is expected to aid in the design of new metal current collectors for seawater batteries in the future.

A current collector refers to a material that serves as a pathway for electron movement. Among these, the positive current collector of a seawater battery consists of a carbon current collector and a titanium metal current collector. Titanium metal current collectors are widely used due to their high stability when interacting with seawater.

On the other hand, corrosion of carbon current collectors, which frequently occurs in seawater batteries and other batteries, is cited as a major cause of weakened cycle stability. Therefore, inhibiting the corrosion of carbon current collectors is of paramount importance for achieving high stability.

The research team devised a method to increase the efficiency of seawater batteries by preventing corrosion of the entire current collector. The TiC-coated titanium (Black Ti) developed by the research team demonstrated chemical, electrochemical, and mechanical stability in a seawater environment.

When the developed current collector is used in a seawater battery, the coin-type cell shows a 4-fold improvement in cycle performance and a 30% improvement in output performance compared to the existing one, and the voltage gap is reduced to 20%.

In addition, it was successfully applied to high-capacity prismatic type cells, yielding results showing that output performance increased by 15% and resistance and voltage gap decreased by 25% and 20%, respectively.

The research team quantitatively and qualitatively confirmed that the performance improvement was due to the inhibition of corrosion of the carbon current collector.

"Seawater batteries are next-generation battery systems that use seawater as a cathode material," said researcher Yoon-Jong Cho, the first author. "Through this research, the current collector fabricated in a simple manner could contribute to accelerating the commercialization of not only seawater batteries but also fuel cells, flow batteries, and metal-air batteries."

This research was conducted with support from the National Research Foundation of Korea (NRF), the Korea Energy Technology Evaluation Institute (KETEP), and UNIST, and the results were published online on February 20 in 'Advanced Functional Materials,' a prestigious journal in the field of materials science.