Researchers at the University of Surrey in the UK have uncovered a simple yet powerful method to enhance the performance of sodium-ion batteries – by retaining water within a key material rather than removing it.
The breakthrough, published in the Journal of Materials Chemistry A, could pave the way for greener energy storage and even desalination.
Unlike lithium-ion batteries, which rely on costly and environmentally damaging materials, sodium is abundant and widely available. However, performance limitations have hindered its commercial viability. The Surrey team focused on sodium vanadium oxide, a material typically heat-treated to remove water. Instead, they retained the water, forming a nanostructured sodium vanadate hydrate (NVOH).
In tests, the ‘wet’ version stored nearly twice the charge of standard sodium-ion materials, charged faster, and remained stable over 400 cycles.
“Our results were completely unexpected. 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,” said Dr Daniel Commandeur, Surrey Future Fellow. “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 team also demonstrated electrochemical desalination using the material in salt 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,” added Dr Commandeur.
This innovation could accelerate the shift to safer, low-cost sodium-ion batteries for grid storage and EVs.
Image: University of Surrey
