PNNL develops new phenazine-based compound for redox flow batteries: An organic molecule used in dyes and antibiotics may be the key to less expensive, more efficient redox flow batteries. Scientists at the Department of Energy’s Pacific Northwest National Laboratory developed a highly reversible, water soluble material based on phenazine. The compound could serve as an alternative to vanadium, which is used in grid-scale batteries to store electricity.
PNNL researchers developed the material in an effort to reduce the cost of redox flow batteries. Currently, many commercial redox flow batteries use a vanadium-based electrolyte. Vanadium is primarily used in steel making and as commodity materials, its costs can vary based on supply and demand. To overcome these cost constraints, PNNL scientists have developed a new phenazine-based material as an alternative to vanadium as described in Nature Energy.
“This is a major development for organic flow batteries,” said Imre Gyuk, Director of Energy Storage at DOE’s Office of Electricity which supported this work at PNNL. “There is much interest around the potential for water soluble, organic redox materials as an alternative to vanadium-based batteries. However, the problem is getting the materials to actually dissolve in water and maintain the desired electrochemical properties.”
The PNNL research team, led by chief scientist Wei Wang, knew that phenazine — a naturally occurring compound — possesses the needed redox reactions; but, was not water soluble. So, PNNL researchers developed a method of chemically modifying phenazine, producing a water-soluble derivative that also optimizes its redox properties. When dissolved in the electrolyte solution, the team found 90 percent of the dissolved phenazine available to carry energy.
According to Wang, modifying the phenazine is straightforward and scalable. While the team still needs to conduct a cost analysis, phenazine precursor chemicals are readily available and inexpensive.
“The results are promising,” said Wang. “We have not only developed a viable alternative to vanadium, we have developed a structured, virtual screening approach that will help us identify new promising materials.”
PNNL will continue testing a phenazine-based anolyte (negative electrolyte) and plans to develop a corresponding catholyte (positive electrolyte). Combined, the solutions could lead to new type of redox flow battery.
The work was funded by the DOE’s Office of Electricity with mass spectrometry, nuclear magnetic measurements, and theoretical calculations performed at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility at PNNL.
EMSL, the Environmental Molecular Sciences Laboratory, is a DOE Office of Science user facility. Located at Pacific Northwest National Laboratory in Richland, Wash., EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. Its integrated computational and experimental resources enable researchers to realize important scientific insights and create new technologies. Follow EMSL on Facebook, LinkedIn and Twitter.
Pacific Northwest National Laboratory is the nation’s premier laboratory for scientific discovery in chemistry, earth sciences, and data analytics and for solutions to the nation’s toughest challenges in energy resiliency and national security. Founded in 1965, PNNL is operated by Battelle for the U.S. Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit PNNL’s News Center. Follow us on Facebook, Google+, Instagram, LinkedIn and Twitter.
Susan Bauer, PNNL, (509) 372-6083