July 10, 2023 News Release
Next-generation Flow Battery Design Sets Records
Sugar additive plays a surprise role, boosting flow battery capacity and longevity for this grid energy resilience design
Karyn Hede, PNNL

RICHLAND, Wash.—A common food and medicine additive has shown it can boost the capacity and longevity of a next-generation flow battery design in a record-setting experiment.

A research team from the Department of Energy’s Pacific Northwest National Laboratory reports that the flow battery, a design optimized for electrical grid energy storage, maintained its capacity to store and release energy for more than a year of continuous charge and discharge.


Flow batteries provide long-lasting, rechargeable energy storage, particularly for grid reliability. Unlike solid-state batteries, flow batteries store energy in liquid electrolyte, shown here in yellow and blue. Researchers at PNNL developed a cheap and effective new flow battery that uses a simple sugar derivative called ?-cyclodextrin (pink) to speed up the chemical reaction that converts energy stored in chemical bonds (purple to orange), releasing energy (electrons) to power an external circuit. A parallel reversible process (red-green) in the positive catholyte solution balances the positive and negative charges during charge and discharge. (Animation by Sara Levine | Pacific Northwest National Laboratory)

The study, just published in the journal Joule, details the first use of a dissolved simple sugar called ?-cyclodextrin, a derivative of starch, to boost battery longevity and capacity. In a series of experiments, the scientists optimized the ratio of chemicals in the system until it achieved 60 percent more peak power. Then they cycled the battery over and over for more than a year, only stopping the experiment when the plastic tubing failed. During all that time, the flow battery barely lost any of its activity to recharge. This is the first laboratory-scale flow battery experiment to report more than a year of continuous use with minimal loss of capacity.

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The work on flow batteries is part of a large program at PNNL to develop and test new technologies for grid-scale energy storage that will be accelerated with the opening of PNNL’s Grid Storage Launchpad in 2024.

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