The Key to Enhancing Next-Generation Seawater Battery Performance Is the 'Black Coat'

UNIST Professor Dongwook Lee's Team Coats Titanium with TiC

Why did seawater batteries, considered the next-generation energy source, choose black clothing?

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

In particular, during this process, the team discovered that the corrosion of the carbon current collector was suppressed and systematically analyzed this phenomenon, which is expected to aid the design of new seawater battery metal current collectors in the future.

The current collector refers to the material that serves as the pathway for electron movement. Among them, the anode current collector of seawater batteries consists of carbon current collectors and titanium metal current collectors. Titanium metal current collectors are widely used due to their high stability when interacting with seawater.

However, corrosion of the carbon current collector, which often occurs in seawater batteries and other batteries, is considered a major cause of reduced cycle stability. Therefore, suppressing the corrosion of the carbon current collector was important to achieve high stability.

Comparison of battery electron mobility between conventional titanium (Normal Ti) and titanium coated with TiC (Black Ti).

The research team devised a method to prevent corrosion of the current collector and improve the efficiency of seawater batteries. The titanium coated with TiC developed by the team (Black Ti) demonstrated chemical, electrochemical, and mechanical stability in seawater environments.

When the developed current collector was used in seawater batteries, the coin-type cell showed a fourfold improvement in cycle performance, a 30% increase in output performance, and a 20% reduction in voltage gap compared to existing cells.

They also succeeded in applying it to the prismatic-type cell, a large-capacity cell, resulting in a 15% increase in output performance and reductions of 25% and 20% in resistance and voltage gap, respectively. The research team quantitatively and qualitatively confirmed that the performance improvement was due to the suppression of corrosion in the carbon current collector.

Yoonjong Cho, the first author of the study, said, “Seawater batteries are next-generation battery systems that use seawater as the anode material,” adding, “This research could contribute to accelerating the commercialization of not only seawater batteries but also fuel cells, flow batteries, and metal-air batteries by using a simply fabricated current collector.”

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

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