New battery idea gets lots of power out of unusual sulfur chemistry
When the battery begins to discharge, the sulfur in the cathode begins to lose electrons and form sulfur tetrachloride (SCl4), using chloride, he stole the electrolyte. When the electrons enter the anode, they combine with the sodium, which plates onto the aluminum, forming a layer of metallic sodium. Obviously this wouldn’t work with an aqueous electrolyte, given how powerfully sodium reacts with water.
High capacity
To form a working battery, the researchers separated the two electrodes using a fiberglass material. They also added a porous carbon material to the cathode to prevent sulfur tetrachloride from diffusing into the electrolyte. They used various techniques to confirm that sodium was deposited on the aluminum and that the reaction at the cathode occurred via sulfur dichloride intermediates. They also determined that sodium chloride was a poor source of sodium ions because it tended to precipitate on some solid battery materials.
The battery was also quite stable, surviving 1,400 cycles before experiencing a significant drop in capacity. Higher charging rates caused capacity to decline more quickly, but the battery does an excellent job of maintaining charge when not in use, retaining over 95% of its charge even when unused for 400 days.
Although researchers provide some capacity measurements by weight, they do not do so for an entire battery, but rather focus on parts of the battery, such as sulfur or total electrode mass.
But considering both electrodes, the energy density can reach more than 2,000 watt hours per kilogram. While this will undoubtedly decrease with the total mass of the battery, it’s hard to imagine that it wouldn’t outperform existing sodium-sulfur or sodium-ion batteries.
Beyond capacity, the big advantage of the proposed system seems to be its price. Considering the raw materials, the researchers estimate their cost to be about $5 per kilowatt hour of capacity, less than a tenth the cost of current sodium batteries.
Again, there is no guarantee that this work can be scaled up to manufacturing in a way that remains competitive with current technologies. However, if the materials used in existing battery technologies become expensive, it is reassuring to be able to explore other options.
Nature, 2026. DOI: 10.1038/s41586-025-09867-2 (About DOIs).
