Researchers at KAIST (Korea Advanced Institute of Science and Technology) have reported a 67 per cent reduction in the production time for V3.5+ vanadium electrolyte, cutting it to roughly one third of the conventional process, according to a study published in Advanced Energy Materials and reported on 1 November 2026.
The V3.5+ mixed-valence solution has vanadium averaging halfway between the +3 and +4 oxidation states. That matters for manufacturing: a single electrolyte can be loaded into both tanks of a flow battery at assembly, rather than preparing and balancing separate positive and negative solutions. For vanadium redox flow battery (VRFB) suppliers, electrolyte conditioning is a throughput and cost bottleneck, so any reduction in processing time is commercially relevant.
The bottleneck sits at +4.1
The team identified a kinetic constraint — a rate-determining step — at an average vanadium oxidation state of about +4.1, partway through the reduction to the mixed +3.5 state. Conventional production uses chemical reduction throughout the process. The KAIST approach switches to catalytic reduction at approximately +4.1, bypassing the slowest stage, which is where the 67 per cent time saving originates.
Corresponding author Hee-Tak Kim, Professor in the Department of Chemical and Biomolecular Engineering at KAIST, framed the result around the practical constraints of electrolyte manufacturing.
Platinum reuse and impurity removal
The platinum-on-carbon (Pt/C) catalyst was reused more than 2,500 times without a notable performance drop — a figure that determines economic viability, since the cost of platinum must be spread thinly across production volumes. The process also removes residual oxalic acid, an impurity carried over from conventional chemical reduction that can degrade battery performance. That eliminates the need for a separate purification step, or for accepting a slow performance penalty over the service life of the battery.
Key claims: 67% shorter production time; V3.5+ electrolyte loaded into both tanks; Pt/C reused over 2,500 times; oxalic acid impurity removed in-process.
Caveats before scale-up
The report cautions that 2,500 catalyst reuses is a laboratory result under cleaner conditions than industrial feedstock streams, where trace contaminants in commercial vanadium sources commonly poison catalysts, and no production scale was given. A 67 per cent time saving at lab volumes is a chemistry demonstration whose survival on scale-up depends on heat and mass transfer in much larger reactors and on continuous rather than batch platinum recovery. Production time is also only one input to electrolyte cost.
The research was supported by Lotte Chemical, and the release frames the work around AI data centres driving sharp increases in projected electricity demand and storage needs — a framing attributed to the publisher rather than the paper.
This article was assisted by AI analysis. Please refer to the original source for official information.