Researchers at Pacific Northwest National Laboratory (PNNL) have demonstrated the use of sugar water to improve the performance of flow batteries for grid-scale energy storage.
Flow batteries, two-chamber devices containing a liquid electrolyte, are being actively developed around the world as grid-level energy storage solutions for renewable energy systems.
PNNL has made a significant breakthrough by developing an electrolyte additive called β-cyclodextrin. Derived from a simple sugar used in food and pharmacology, this additive has shown significant results in flow batteries. The PNNL team achieved a 60 percent increase in the research current battery’s peak power.
β-Cyclodextrin accelerates the electrochemical reaction responsible for energy storage and release in flow batteries. Unlike previous methods, the sugar works as a dissolved solution rather than a solid applied to the surface, a first for flow batteries. Findings, published in Jouledemonstrate the ability of the sugar additive to accept positively charged protons, which promotes the balanced movement of negative electrons during battery discharge.
“This is a completely new approach to developing a flow battery electrolyte,” said Wei Wang, a PNNL battery researcher. “We showed that you can use a completely different type of catalyst designed to speed up energy conversion. And also, because it’s dissolved in a liquid electrolyte, it eliminates the chance of solids coming off and fouling the system.
The research aims to reduce reliance on rare earth minerals and toxic substances for battery energy storage by promoting a more sustainable approach that reflects synthesis methods from the pharmaceutical and food industries, rather than relying on heavy mineral mining.
Continuing their research, the team is investigating alternative compounds that are similar to β-cyclodextrin, but smaller. While adding simple sugar thickens the liquid, as does adding honey to tea, this presents challenges for a flow-based system. However, the researchers concluded that the catalytic advantages of sugar outweighed the viscosity disadvantages.
This research is part of a larger PNNL program to develop and test grid-scale energy storage technologies. The university is scheduled to open a Grid Storage Launchpad in 2024. Learn more about licensing this PNNL-developed technology here.