A team from the University of Surrey finds that keeping water inside a layered sodium vanadate hydrate (NVOH) cathode dramatically boosts sodium-ion battery performance, nearly doubling energy storage and enabling faster charging compared with traditional dehydrated cathodes.

This dual functionality points to future designs where seawater could serve as an electrolyte, enabling simultaneous energy storage and water purification with potential cost and environmental benefits.

Dr. Daniel Commandeur notes the findings could unlock new possibilities for how NVOH is used, potentially delivering safer, cheaper, and more environmentally friendly energy storage solutions.

Tests in seawater show the hydrated material remains functional and enables electrochemical desalination, with a graphite electrode removing chloride ions, suggesting seawater batteries could store energy while desalinating water.

In saltwater, NVOH continues to operate and contributes to desalination by removing sodium ions from solution while a graphite electrode extracts chloride ions, creating an electrochemical desalination effect that can power the battery and purify water.

The study envisions applications in large-scale renewable energy storage and electric vehicles, leveraging abundant sodium and seawater to move sodium-ion technology toward practical, commercially viable deployment.

If scalable, this approach could advance sodium-ion technology for grid storage and renewable integration due to sodium's abundance and low cost.

Hydration appears to enhance sodium-ion diffusion within the layered structure, improving charge kinetics and energy density.

The discovery challenges the conventional rule of drying battery materials and suggests embracing hydration chemistry to optimize performance.

NVOH stores nearly twice as much charge as dehydrated cathodes, maintains stable energy retention for over 400 charge cycles, and offers faster charging and higher capacity.

The hydrated nanostructured sodium vanadate demonstrates superior energy density and cycle stability, positioning it among the top sodium-ion cathodes reported.

Retaining water during processing runs counter to common practice, challenging long-held assumptions and yielding unexpectedly strong results.