US start-ups are working to commercialise sodium-ion batteries, a technology that has been a research goal for decades.
These batteries use sodium, the same element found in table salt, as a replacement for lithium and other scarce minerals currently critical to battery production.
Why sodium makes sense
Sodium is abundant across the Earth, unlike the specialist minerals used in most of today's batteries.
A battery design from California-based Inlyte Energy, based in San Leandro, is built from just four ingredients: iron powder, steel, aluminium oxide and food-grade table salt.
The safety advantage
A key benefit of sodium-based batteries is their behaviour under heat.
Conventional lithium grid batteries carry a risk known as thermal runaway, where one overheating cell can ignite the cells around it.
Sodium cells run cool enough to avoid that risk altogether.
Why that changes the cost of cooling
Because sodium cells do not need the complex liquid cooling systems used in lithium batteries, they can instead be cooled passively using air.
Eliminating liquid cooling matters significantly, since one company founder estimates that cooling systems account for roughly 90% of the operating costs of conventional lithium grid batteries.
Removing pumps and liquid coolant also reduces the number of components that can eventually break down.
Why they won't replace car batteries
A notable limitation of sodium-based batteries is that they store less energy per gram than lithium.
That means electric vehicles will continue to rely on lithium batteries for the foreseeable future, since weight remains critical for driving range.
Where sodium batteries actually fit
Despite that weight disadvantage, sodium batteries are well suited to energy grids and data centres, neither of which requires the lightweight properties essential for vehicles.
These batteries are designed to stockpile solar and wind power for release when renewable generation is low, potentially replacing gas plants and diesel generators for that purpose.
Who is building them
Several companies are advancing the technology.
Peak Energy, founded by former Tesla engineers, plans to begin production in Sacramento in 2027.
General Motors is separately designing its own sodium-ion cells, a sign that interest in the technology now extends well beyond dedicated battery start-ups and into mainstream vehicle manufacturing.