Scientists at the University of Surrey have achieved a remarkable breakthrough in sodium-ion battery technology — one that could double energy storage capacity and, perhaps more surprisingly, help convert seawater into drinkable water. The secret behind this advance is deceptively simple: leaving water inside the battery material instead of removing it.
A Counterintuitive Discovery Rewrites the Rulebook
Sodium vanadium oxide is a well-established compound in battery research. For years, scientists have routinely applied heat treatments to strip out the material’s natural water content, based on the assumption that moisture degrades performance. A team led by Dr. Daniel Commandeur at the University of Surrey School of Chemistry and Chemical Engineering chose to challenge that long-held practice — and the results completely overturned expectations.
When the material was allowed to retain its water, forming what researchers call nanostructured sodium vanadate hydrate (NVOH), its battery performance improved dramatically. Testing showed that the hydrated version could hold nearly twice as much charge as typical sodium-ion cathode materials. It also charged faster and remained stable through more than 400 charge cycles, ranking it among the best-performing cathodes ever documented for sodium-ion batteries.
“Our results were completely unexpected,” said Dr. Commandeur. “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. The material showed much stronger performance and stability than expected and could even create exciting new possibilities for how these batteries are used in the future.”
The findings were published in the Journal of Materials Chemistry A, with co-authors Vlad Stolojan, Monica Felipe-Sotelo, James Wright, David Watson, and Robert C. T. Slade.
When Salt Water Becomes an Opportunity
The research team pushed the testing further by introducing the NVOH material directly into a salt water environment — one of the harshest conditions any battery electrode can face. The results were eye-opening. Not only did the battery continue to function effectively, but it also pulled sodium ions directly out of the solution. A graphite electrode working alongside it extracted chloride ions through a process known as electrochemical desalination.
Put simply: the battery was filtering the water at the same time it was storing energy.
“Being able to use sodium vanadate hydrate in salt water is a really exciting discovery, as it shows sodium-ion batteries could do more than just store energy — they could also help remove salt from water,” said Dr. Commandeur. “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.”
Why Sodium Makes Sense
Lithium-ion batteries currently dominate the energy storage market, but they come with significant costs — both financial and environmental. Lithium mining is resource-intensive, geographically concentrated, and linked to considerable ecological damage. Sodium offers a very different picture: it is far more abundant, widely available around the world, and considerably cheaper.
Sodium-ion batteries have long been considered an appealing alternative, but matching lithium’s performance has been the persistent stumbling block. This discovery narrows that gap in a meaningful way, making sodium-ion technology a much more credible contender.
Simpler to Make, Closer to Market
One underappreciated advantage of this breakthrough is its simplicity. NVOH is not a new or exotic compound — it has existed for years and is already well understood by the scientific community. The only change the Surrey team made was skipping the heat-treatment step that normally removes water. Eliminating this step also simplifies manufacturing, which could accelerate the path to large-scale commercial production of high-performance sodium-ion batteries.
Dual-Purpose Technology With Global Reach
The potential applications span multiple sectors. On the energy side, sodium-ion batteries based on NVOH could serve as cost-effective storage systems for renewable energy grids, helping balance the fluctuating output of solar and wind power. They also hold real promise as a more affordable alternative in the electric vehicle market.
The desalination capability adds an entirely new dimension. Coastal regions and island communities that face freshwater shortages could one day benefit from systems that simultaneously store energy and produce clean drinking water — addressing two of the world’s most pressing challenges with a single device. The University of Surrey team’s discovery represents a genuine step toward that future.
