Researchers at the University of Surrey have stumbled onto something counterintuitive: the way to make sodium-ion batteries work better might be to stop trying to remove the water from them.
For years, scientists have been heat-treating sodium vanadium oxide—a cheap, abundant material—to drive out moisture, assuming water would degrade performance. Daniel Commandeur and his team decided to test the opposite assumption. The result: a material that stores nearly twice as much charge as conventional sodium-ion batteries and holds up through more than 400 charge cycles.
"Our results were completely unexpected," Commandeur said. "Sodium vanadium oxide has been around for years, and people usually heat-treat it to remove the water because it's thought to cause problems. We decided to challenge that assumption, and the outcome was far better than we anticipated."
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Start Your News DetoxWhy this matters: Lithium-ion batteries have dominated energy storage for decades, but they depend on materials that are expensive and environmentally costly to extract. Sodium sits in seawater and rock deposits everywhere. If sodium batteries can match lithium's performance at a fraction of the cost, they could reshape how we store renewable energy on the grid and power electric vehicles.
A Material That Does Two Jobs
The team tested their "wet" sodium vanadate material in salt water—one of the harshest conditions imaginable. Not only did it survive; it thrived. While the battery stored energy, the electrode simultaneously removed sodium ions from the solution. A separate graphite electrode extracted chloride. The net result: electrochemical desalination happening as a side effect of the charging process.
This opens an unexpected door. "Being able to use sodium vanadate hydrate in salt water is a really exciting discovery," Commandeur noted, "as it shows sodium-ion batteries could do more than just store energy—they could also help remove salt from water. In the long term, that means we might be able to design systems that use seawater as a completely safe, free, and abundant electrolyte, while also producing fresh water as part of the process."
The finding, published in the Journal of Materials Chemistry A, suggests a future where the same device that powers your neighborhood or charges your car might simultaneously convert seawater into drinking water. The practical advantages stack up: simpler manufacturing, lower costs, abundant raw materials, and a performance profile that rivals what lithium-ion systems deliver today. That's the kind of convergence—where solving one problem helps solve another—that tends to accelerate real-world adoption.
