The technology behind sodium-ion batteries just got a whole lot more advanced thanks to one small tweak in their design. Scientists at the University of Surrey discovered that by charging traditional approaches to using nanostructured sodium vanadate hydrate (NVOH), a pre-existing sodium-based material, batteries not only perform better, they can also desalinate water, presenting a surprising and useful dual functionality.
Typically, scientists remove the water content that naturally occurs in NVOH, in keeping with standard practice. But the research team at Surrey tested what would happen if they left the material in its natural, hydrated state. The result was a battery that holds double the charge of a typical model, or about as much as some of the best-performing cathodes on the market. Interesting Engineering reports that compared to traditional sodium-ion battery models, the new NVOH model “stores more charge, charges faster, and remains stable for over 400 charge cycles.” The findings are detailed in a paper published in the scientific publication Journal of Materials Chemistry A.
“Our results were completely unexpected,” said Surrey Future Fellow Dr. Daniel 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.”
Part of that surprising outcome was the discovery that this technology can also be used to desalinate water. “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,” Dr. Commandeur went on to say. “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.”
This compound breakthrough could have serious disruptive potential for the booming battery storage sector, as it could allow sodium-ion batteries to become more competitive with lithium-ion batteries, which currently dominate the market. At present, lithium-ion batteries power 70 percent of all rechargeable devices, from smartphones to EV batteries to grid-scale energy storage.
Sodium-ion batteries have been gaining favor in research and development spaces for some time now as a potential alternative to lithium-ion batteries. Breakthroughs for lithium-ion development, design, deployment have been stacking up, but the technologies have nevertheless struggled to challenge lithium’s dominance. Lithium-ion batteries have become nearly ubiquitous thanks to lithium’s excellent energy density and ability to perform well in cold temperatures. These attributes make the metal “indispensable for high-performance applications” according to EV World. But lithium has some serious downsides, including negative environmental impacts and geopolitically fraught supply chains largely controlled by China.
While lithium boasts some critical attributes that make it a storage superstar, sodium also has some unique selling points that could make it the next industry darling. "Sodium is a much more sustainable source for batteries [than lithium]," James Quinn, chief executive of UK-based battery technology company Faradion, told the BBC. "It's widely available around the world, meaning it's cheaper to source, and less water intensive to extract," says Quinn. "It takes 682 times more water to extract one tonne of lithium versus one tonne of sodium. That is a significant amount."
Industry insiders say that sodium-ion batteries are on the cusp of large-scale commercialization as technologies advance and prices fall. But we still shouldn’t expect an all-out replacement of lithium-ion batteries. The future of batteries isn’t about lithium versus sodium – it will require both. Taking advantage of both models for their unique attributes can create a more versatile and resilient energy storage sector, among other critical applications.
By Haley Zaremba for Oilprice.com