Researchers at Monash University have developed a water-based battery that they claim could help store rooftop solar energy “more safely, cheaply and efficiently”.
The compact, high-performance flow batteries are set to offer a more affordable alternative to the $10,000 lithium-ion systems currently powering many homes.
Flow batteries have traditionally been used in large-scale energy storage due to their large size and slow charge speeds.
Monash engineers have developed a new membrane design that improves charging speeds, making the technology better suited for households and mid-scale facilities, not just large commercial users.
“We’ve taken safe, affordable chemistry and made it fast enough to capture rooftop solar in real time,” the study’s first author and PhD candidate at the Department of Materials Science and Engineering, Wanqiao Liang, said.
“We’ve engineered a membrane that finally makes organic flow batteries competitive for residential and mid-scale storage.
“The key was improving ion selectivity; letting the good ions through quickly while keeping unwanted ones out.”
Advantages of water-based flow batteries
The flow batteries store energy in liquids rather than solid materials like those found in lithium-ion batteries, making them cheaper, safer and easier to scale.
“Flow batteries work a bit like two fish tanks joined by a membrane barrier that allows ions to pass through, enabling energy storage and release,” CSIRO research scientist and study co-author Dr Cara Doherty said.
“We’ve developed a new type of membrane inside the battery that guides the flow of materials better – kind of like adding lanes to a highway. That means faster charging, longer battery life and better performance overall.”
Liang said the tests her team conducted found the newly developed water-based flow batteries outperformed the industry-standard Nafion membrane in both speed and stability – reportedly running 600 high-current cycles with virtually no capacity loss.
Beyond efficiency, Liang said the battery’s safety features and the ready availability of its components set it apart from lithium-ion batteries.
“It’s non-toxic, non-flammable and made from abundant materials,” Liang added.
The team is now 3D printing prototype systems and testing them under real-world conditions. Liang noted that if the tests are successful, this technology could be in the market in a few years.
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