They power tiny phones and two-tonne electric cars. They form the guts of a growing number of grid-storage systems¹ that smooth the flow of electricity from wind and solar power stations. Without them, the electrification needed to avoid the worst effects of global warming would be unimaginable.

But lithium-ion (Li-ion) batteries have downsides. Lithium is scarce, for one. And the best Li-ion batteries, those with layered-oxide cathodes, also require cobalt and nickel. These metals are scarce, too — and cobalt is also problematic because a lot of it is mined in the Democratic Republic of Congo, where working conditions leave much to be desired. A second sort of Li-ion battery, a so-called polyanionic design that uses lithium iron phosphate (LFP), does not need nickel or cobalt. However, such batteries cannot store as much energy per kilogram as layered-oxide ones.

A group of companies, though, think they have an alternative: making batteries with sodium instead. Unlike lithium, sodium is abundant: it makes up most of the salt in the oceans. And chemists have found that layered-oxide cathodes which use sodium rather than lithium can get by without cobalt or nickel to increase their quality. The idea of making sodium-ion (Na-ion) batteries at scale is therefore gaining traction. Engineers are adjusting designs. Factories, particularly in China, are springing up. For the first time since the Li-ion revolution began, lithium’s place on the electrochemical pedestal is being challenged.

(www.economist.com, 25.10.2023. Adaptado.)

1 grid-storage system: sistema de armazenamento de energia elétrica.