New redox flow battery could help unleash renewable energy

Scientists at USC Dornsife College of Letters, Arts and Sciences have developed a new battery that could solve the electricity storage problem that limits the widespread use of renewable energy.

The technology is a new spin on a known design that stores electricity in solutions, sorts the electrons and releases power when it’s needed. So-called redox flow batteries have been around a while, but the USC Dornsife researchers have built a better version based on low-cost and readily available materials.

“We have demonstrated an inexpensive, long-life, safe and eco-friendly flow battery attractive for storing the energy from solar and wind energy systems at a mass scale,” said Sri Narayan, professor of chemistry, lead author for the study and co-director of USC Dornsife’s Loker Hydrocarbon Research Institute.

The study was published in the Journal of the Electrochemical Society.

Overcoming a major problem for renewable energy

Energy storage is a big hurdle for renewable power because power demand doesn’t always coincide with when wind turbines spin or sunshine hits solar panels.

The scientists focused on the redox flow battery because it’s proven technology and has already been deployed in limited applications. It uses fluids to store electrochemical energy, sorting electrons and recombining by reduction and oxidation and then releasing them to make electricity as needed.

The key innovation achieved by the USC Dornsife scientists involves using different fluids: an iron sulfate solution and a type of acid.

While the two compounds are well known individually, it’s the first time they’ve been combined to prove their potential for large-scale energy storage.

New battery proves durable and sustainable

In tests at USC Dornsife, the researchers also found that the battery can cycle, or recharge, hundreds of times with virtually no loss of power, unlike competing technologies. Durability for energy storage systems is important for large-scale use.

The technology also has advantages over lithium-ion battery storage. The proliferation of consumer electronics and electric vehicles, powered by lithium-ion batteries, creates scarcity for the element, which drives up costs. In turn, those economics make other, less expensive energy storage options more appealing, the study said. Also, lithium-ion batteries don’t last as long due to recharging, as most people who’ve recharged cellphones and laptops know.

“The … flow battery system presents a good prospect for simultaneously meeting the demanding requirements of cost, durability and scalability for large-scale energy storage,” the study said.

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About the study

Study authors include Narayan, Bo Yang, Advaith Murali, Archith Nirmalchandar, Buddhinie Jayathilake and G. K. Surya Prakash of the USC Loker Hydrocarbon Research Institute headquartered at USC Dornsife.

Funding for the study comes from ARPA-E (#DE-AR0000337), the USC Loker Hydrocarbon Research Institute and USC Dornsife’s Department of Chemistry.

Authors Narayan and G.K. Surya Prakash are principals in a startup company that has licensed redox flow battery technology from USC.