Eco-friendly Seawater Battery Inspired by Mussel Adhesion Shows 4x Performance Improvement

UNSIT Research Team

[Asia Economy Reporter Kim Bong-su] Domestic researchers have significantly improved the performance of seawater batteries that generate electricity using seawater, inspired by the excellent underwater adhesion of mussels.

Ulsan National Institute of Science and Technology (UNIST) announced on the 13th that Professor Lee Dong-wook's team from the Department of Energy and Chemical Engineering developed a binder material for seawater batteries that mimics the outstanding underwater adhesion of mussels, greatly enhancing the battery electrode performance.

The anode of a seawater battery consists of a current collector woven from carbon fibers and catalyst particles applied to the fiber surface. The binder is a substance that adheres and fixes the catalyst to the current collector. The binder developed by the research team mimics the adhesive protein components of mussels, exhibiting excellent adhesion even underwater. This technology solves the problem where conventional binders lose significant adhesion in water, unlike in organic solvents. If the current collector and catalyst are not properly adhered, the battery experiences overload (overvoltage) and the current collector is prone to corrosion.

Seawater batteries using the developed binder showed a reduction in overvoltage by up to 60% compared to those using commonly used fluoride-based binders, and electrode performance (difference in charge-discharge overvoltage) improved about fourfold. Electron microscope observations also showed a significant improvement in current collector corrosion. Additionally, catalyst particles were detected inside the binder, indicating that the binder not only prevents corrosion of the current collector but also protects against catalyst detachment.

The research team revealed the reason for the binder's excellent adhesion through surface force measurement experiments and density functional theory analysis. The analysis confirmed that the stronger the interaction forces at the interfaces between the catalyst and binder and between the current collector and binder, the more firmly the catalyst is fixed to the current collector.

Co-first author Ji-eun Choi, a graduate student in the Department of Energy and Chemical Engineering, said, "As a material with strong underwater adhesion as well as carbon corrosion and catalyst detachment prevention properties, this binder can contribute to accelerating the commercialization of not only seawater batteries but also various aqueous metal-air batteries."

Meanwhile, seawater batteries are eco-friendly energy storage devices that store and discharge electricity using seawater. They share the common feature of using water (seawater) as an electrolyte, similar to next-generation high-density energy storage devices such as aqueous metal-air batteries. Conventional batteries typically use hydrophobic organic solvents as electrolytes.

This research was published on the 7th as the outside front cover of the international journal in the energy and materials field, Journal of Materials Chemistry A.

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