British scientists discovered the best sodium batteries in the world, but their laziness led to this achievement

New approach to sodium-ion battery cathodes: water as an active component

Scientists from the University of Surrey (UK) found that retaining water in the structure of a sodium‑vanadate hydrate (NVOH) cathode nearly doubles its capacity.

Typically, when synthesizing such material, dehydration is performed: heating to high temperatures to “eliminate” moisture, assuming it is detrimental to battery performance. The researchers decided otherwise—simply do not remove water. The result exceeded expectations.

How the effect works
- Water separates the layers of the material: water molecules create additional space between layers, facilitating sodium ion penetration.
- The increased volume for ions leads to higher capacity.
- Test cells with wet NVOH endured over 400 charge‑discharge cycles without noticeable degradation.

Moreover, these cathodes exhibit high charging speed and impressive specific capacity, making them among the best on the market for sodium‑ion batteries today.

Why it matters
Metric Traditional NVOH (dehydrated) Wet NVOH Cost High due to complex dehydration Low – simple procedure Safety Medium, overheating possible Very high: water reduces fire risk Material availability Depends on rare elements Uses widely available sodium Environmental friendliness Mining and disposal less “clean” More “green” supply chain Sodium‑ion batteries overall are already considered safer than lithium‑ion. Adding water to the cathode enhances this effect and makes the technology even more attractive for mass deployment.

Not just energy storage
Scientists noted that NVOH remains active even in seawater. This opens prospects for dual use:
1. Energy – electricity storage.
2. Water treatment – desalination of sea water.

In the end, one can create a “smart” battery that simultaneously charges and purifies water, which is especially important for regions with limited freshwater resources.

Conclusion
By leaving moisture in the cathode structure, researchers obtained a material with nearly double capacity, excellent cycle stability, and high safety. This discovery could be key to more affordable, environmentally friendly sodium‑ion batteries, as well as innovative systems for producing fresh water from seawater.