New sodium battery promises more than 5,000 hours of useful life

Engineers in Australia have built a sodium battery that keeps working for more than 5,000 hours in lab tests. It uses a solid, plastic-like core instead of flammable liquid, which makes the whole system much harder to overheat.

The prototype, developed at the University of Queensland, targets battery banks for storing renewable energy on the grid.

By swapping scarce lithium for common table-salt sodium, it promises lower costs and less supply-chain stress for many countries.

Why sodium is getting attention

Sodium sits just below lithium on the periodic table, but it is more abundant and easier to source.

Several research groups now argue that sodium based batteries could cut material costs for large storage projects.

The work was led by Dr Cheng Zhang at the University of Queensland’s Australian Institute for Bioengineering and Nanotechnology (AIBN).

His research focuses on solid-state batteries that pair safer electrolytes with low cost metals such as sodium.

Traditional sodium metal cells use liquid electrolytes that often grow dendrites, tiny metal spikes that pierce internal battery layers. These spikes can short circuit the cell, waste stored energy, and in worst cases start fires.

Dangers lurking inside batteries

Inside every battery sits an electrolyte, a material that lets charged ions move between the two electrodes.

“Most batteries use a liquid electrolyte, but these liquids are flammable and can overheat,” said Dr Zhang.

Solid electrolytes trade that fluid for a solid layer, which improves safety and removes the need for heavy packaging.

Earlier work showed that perfluoropolyether based polymers can support stable sodium cycling at high temperature.

The problem is that a solid must be both strong enough to block growing metal and open enough inside for ions to slip through.

Many candidate materials either crack under stress or slow the ions so much that the battery becomes too sluggish for real use.

The Queensland team tackled that tradeoff by redesigning the electrolyte at the molecular level rather than simply swapping one salt for another.

They wanted a plastic that could flex with the electrodes yet maintain organized pathways for sodium movement deep inside.

Plastic and sodium ions

The new material is a block copolymer, a long chain made from two different repeating segments joined together.

One part of the chain grabs sodium ions, while the other part stays slippery and fluorinated so the polymer does not burn.

When processed correctly, the chains form a body-centered cubic structure, a 3D pattern with connected pockets for the ions.

These pockets link up into tunnels so sodium ions can move with low resistance without letting filaments punch through.

In full cells using a sodium vanadium phosphate cathode, the device kept more than 91 percent of its starting capacity.

It maintained that level after 1,000 rapid charge and discharge cycles at 176 degrees Fahrenheit in the test chamber.

Sodium batteries and energy demand

Unlike many lithium batteries, sodium metal designs do not need cobalt or nickel in their cathodes.

That reduces pressure on supply chains linked to pollution and labor concerns in certain mining regions.

For a power grid with solar panels and wind turbines, stationary batteries help smooth periods when generation drops.

Cells that keep high capacity over years can sit in container sized packs at substations and soak up electricity.

Because sodium comes from common sources such as seawater and rock salt, countries without lithium reserves can build large battery projects.

That diversity in materials can make the global energy system less vulnerable to sudden commodity shocks or export bans.

Next steps for sodium batteries

Lab tests often run batteries at elevated temperatures to boost ion movement, but real devices must perform well at ordinary room conditions.

An Energy and Environmental Science review notes that keeping sodium batteries efficient across wide temperatures remains a key barrier to commercialization.

“This kind of long-term performance is essential for grid-level energy storage,” said Dr Zhang. For the Queensland prototype, the obvious next step is to boost its efficiency when it runs at standard indoor temperatures.

On the materials side, the team experimented with several internal patterns before settling on the one that carried sodium most smoothly.

“We tested a range of internal structures to find the one that would give us the best battery performance,” Zhou said.

If researchers can combine room-temperature efficiency with the safety and lifetime already shown in the lab, sodium metal batteries could anchor large renewable projects.

That shift would ease pressure on lithium supplies while keeping clean energy flowing after sunset and during calm spells.

The study is published in the Journal of the American Chemical Society.

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