Researchers at KAIST have developed a process technology that cuts production time for a key large-capacity battery material by 67%.
The breakthrough comes from overcoming an electrolyte bottleneck that had been the biggest obstacle to commercializing large-capacity batteries, bringing the prospect of massive energy storage systems needed to support the AI data center era a step closer.
KAIST announced Wednesday that a research team led by Kim Hee-tak, a professor in the Department of Chemical and Biomolecular Engineering, has developed a faster production process for the core electrolyte used in vanadium redox flow batteries (VRFB) — a leading candidate for large-scale ESS applications.
VRFBs have drawn attention as an ultra-large battery solution for AI data centers and renewable energy storage. They carry almost no fire risk, and storage capacity can be expanded easily by enlarging the tanks that hold the electrolyte.
Producing the vanadium electrolyte — the battery's "fuel" — in its optimal state (V3.5+) has long been slow and costly, making it the single greatest barrier to commercialization.
The conventional process first produces the electrolyte through chemical reduction, a reaction in which a reducing agent causes vanadium ions to gain electrons. The electrolyte then undergoes electrochemical reduction — a step in which electric current adjusts the electron state of the vanadium ions to the desired level — before the final product is obtained.
The research team became the first in the world to identify that reaction rates drop sharply at a specific stage during the chemical reduction process.
To address this bottleneck, the team redesigned the production process so that a catalytic reduction process using a platinum-carbon (Pt/C) catalyst is applied at that stage, replacing the conventional electrochemical reduction step.
Production time for the key V3.5+ electrolyte fell by 67 percent compared with the conventional method. The redesigned process also eliminated residual oxalic acid — an impurity left over from the reaction that can degrade battery performance. The team further confirmed that the same catalyst can be reused more than 2,500 times without any loss of performance or stability.
"We scientifically identified the conditions under which the catalyst operates stably without degrading in the electrolyte environment, and resolved the production bottleneck facing the industry," Kim said. "We expect this to significantly accelerate the commercialization of large-scale energy storage technology."
The study was led by Seok Gyeong-hwa, a doctoral candidate in KAIST's Department of Chemical and Biomolecular Engineering, as first author. The findings were published online May 7 in Advanced Energy Materials, a leading international journal in the energy field. The paper was selected as the cover article for Issue 34, which is scheduled to be released online in early September. The research was supported by Lotte Chemical.
sjpark@heraldcorp.com
