[LAB Search] 'Next-Generation Battery' Sodium Metal Battery... Development of Ultra-Long Life and Fast Charging Technology

Core Technology for 6 Times Longer Life and Faster Charging/Discharging

Professor Ryu Won-hee's research team from the Department of Chemical Engineering and Biomolecular Engineering at Sookmyung Women's University has developed a core technology that enables sodium metal batteries, recognized as next-generation secondary batteries, to last six times longer and charge/discharge faster than existing ones.

Professor Ryu Won-hee's research team from the Department of Chemical and Biological Engineering at Sookmyung Women's University is taking photographs.
[Photo by Sookmyung Women's University]

The research team introduced a small amount of vinylpyrrolidone-based polar molecules as an interfacial stabilization additive into the electrolyte, creating sodium metal battery technology capable of ultra-long lifespan operation over 5,000 cycles even during rapid charge and discharge.

Existing sodium secondary batteries can significantly reduce battery costs by utilizing abundant sodium instead of rare lithium, but their lower energy density compared to lithium secondary batteries has been a barrier to commercialization. Instead, sodium metal batteries, which use sodium metal as the anode instead of hard carbon anodes with low capacity, are attracting attention as promising technology that can achieve both economic efficiency and high energy.

The sodium metal anode requires stabilization technology because, compared to lithium metal anodes, its high reactivity causes dendrite formation and short circuits, leading to battery explosions, reduced battery life, and safety issues.

In this study, when vinylpyrrolidone molecules were introduced as an electrolyte additive, it was confirmed that even under high current of 5 mA/cm² with repeated rapid charge and discharge causing sodium to repeatedly deposit and dissolve, the sodium metal anode surface remained flat and exhibited stable sodium crystal growth. It was also found to contribute to the formation of a high-quality solid electrolyte interface and maintain a stable structure. Furthermore, it was confirmed that introducing only 1% of the polar electrolyte additive into the electrolyte maintained a cycle life more than six times longer than existing sodium metal batteries under high-speed charge and discharge conditions.

The paper, with master's student Jeon Seo-young from the Department of Chemical Engineering and Biomolecular Engineering at Sookmyung Women's University as the first author, was published as the cover paper of the international journal Advanced Energy Materials on the 6th. This research was supported by the Korea Research Foundation’s Breakthrough 4th Generation Secondary Battery Core Source Technology Development Project and the Korea Institute of Science and Technology’s Future Core Clean Technology Development Project.

Professor Ryu said, "This research achievement addresses the low energy density problem of sodium secondary batteries, which have price competitiveness but were considered a barrier to commercialization, and simultaneously secures battery stability and rapid charge/discharge performance, suggesting the possibility of replacing existing lithium secondary batteries."