Chinese scientists have unveiled a new sodium–sulphur battery design that could one day undercut lithium-ion on both price and performance.

The development may have big implications for grid-scale storage and the renewable energy transition.

Published in Nature, the research describes an “anode-free” sodium–sulphur (Na–S) battery that operates at room temperature and delivers a discharge voltage of about 3.6 volts.

This is comparable to many lithium-ion cells and far higher than earlier Na–S designs, which typically struggled to reach 1.6V.

The team claims the prototype can achieve energy densities above 2,000 watt-hours per kilogram when using a catalyst, a figure that would put it in the same league as – or even ahead of – today’s best lithium-based cells, at least at the level of active materials in the lab.

The chemistry also relies on extremely cheap and abundant ingredients: sodium, sulphur, aluminium and a chlorine-based electrolyte.

Based on raw material costs, the researchers estimate the technology could be produced for around A$7.50 per kilowatt-hour – a fraction of the cost of current lithium-ion and even existing sodium-based batteries.

Sulphur has long been seen as a “holy grail” material for batteries because of its theoretical energy capacity, but it usually causes rapid degradation.

The Chinese team says it has avoided this by using a different, high-valence sulphur reaction and a specially formulated sodium dicyanamide electrolyte that is also non-flammable, improving safety.

In testing, the cells reportedly survived around 1,400 charge–discharge cycles before significant capacity loss and retained about 95% of their charge after sitting idle for more than a year – an attractive trait for grid storage where batteries may spend long periods unused.

There are still major hurdles. The electrolyte is corrosive and difficult to handle and the impressive performance figures come from lab-scale cells rather than fully packaged commercial batteries.

Even so, for countries like Australia investing heavily in solar and wind, a breakthrough in ultra-cheap, long-life storage would be a game changer.

If the technology can be industrialised, it could dramatically reduce the cost of storing renewable energy and ease pressure on lithium supply chains.