The research, published in the Journal of Materials Chemistry A, found that a commonly studied sodium-based compound performs dramatically better when its natural water content is preserved. The findings could accelerate the development of safer, more affordable energy storage – and may even pave the way for future systems that turn seawater into drinking water.
Revolutionary approach to battery chemistry
Unlike lithium, which relies on expensive and environmentally damaging mining processes, sodium is abundant and widely available. However, creating sodium-ion batteries that can rival the energy density and efficiency of lithium cells has proved difficult.
The Surrey team’s breakthrough centres on a material called sodium vanadium oxide, or nanostructured sodium vanadate hydrate (NVOH). Traditionally, researchers have heat-treated the material to remove water, assuming it interferes with performance. Instead, the team discovered that leaving the water in place nearly doubled the material’s charge capacity and improved its stability, enabling it to withstand more than 400 charge cycles.
Dr Daniel Commandeur, Research Fellow at the University of Surrey’s School of Chemistry and Chemical Engineering and lead author of the study, said: “Our results were completely unexpected. Sodium vanadium oxide has been around for years, and people usually remove the water because it’s thought to cause problems. We challenged that assumption – and found the material performed far better and remained stable for longer.”
Energy storage and desalination potential
The team also explored how the material behaves in salt water – one of the harshest environments for battery operation. Remarkably, the NVOH material continued to function effectively while simultaneously removing sodium and chloride from the solution, a process known as electrochemical desalination.
Dr Commandeur explained: “Being able to use sodium vanadate hydrate in salt water is a really exciting discovery. It shows that sodium-ion batteries could do more than store energy – they might also help remove salt from seawater. In future, that could mean systems that use seawater as a safe, free and abundant electrolyte, while producing fresh water as part of the process.”
Towards sustainable large-scale storage
The research offers a simpler and more sustainable route to manufacturing sodium-ion batteries capable of supporting the transition to renewable energy. Using earth-abundant materials could reduce production costs and environmental impact, making the technology attractive for grid storage, transport electrification and other large-scale applications.
The discovery marks an important step in the global search for cleaner, more accessible energy solutions – and adds another potential benefit: helping to address the planet’s growing need for fresh water.
