Sodium-ion batteries for electric vehicles and energy storage are moving toward the mainstream. Wider use of these batteries could lead to lower costs, less fire risk, and less need for lithium, cobalt, and nickel.
On November 18, CATL, the world’s largest battery manufacturer, announced its second-generation sodium-ion battery, mass production of which would begin in 2027. The China-based company said the new battery has an energy density of 200 watt-hours per kilogram, which is an increase from 160 watt-hours per kilogram for the previous generation that launched in 2021. Higher energy density in an EV battery translates into more driving range.
On Nov. 21, a consortium of seven US national laboratories announced a new initiative in which they would spend $50 million to foster collaboration to accelerate the development of sodium-ion batteries. The partnership is led by Argonne National Laboratory in the Chicago area.
The two announcements are part of a larger shift as governments, researchers, and companies look for alternatives to lithium-ion batteries, the dominant technology for EVs and energy storage.
For now, there are no passenger cars or trucks sold in the United States that use sodium-ion batteries. Some sodium-ion models are available in China and countries that import vehicles from China.
“The reason we’re pursuing this is very simple,” said Venkat Srinivasan, a battery scientist at Argonne and the director of the new collaboration. “It’s because the huge demand in lithium-ion batteries has meant that we have a supply-chain constraint.
“We have a problem with cobalt. We have a problem with nickel,” he said, naming two of the metals often used in lithium-ion batteries.
Cobalt, nickel, and lithium carry a variety of concerns, including the environmental damage of mining. Also, much of the supply is controlled by US geopolitical rivals such as China, and some of the mining takes place in countries with inadequate labor standards.
In contrast, a sodium-ion battery relies on an element—sodium—that you can find in table salt and ocean water.
Among the other benefits, sodium-ion batteries perform better than lithium-ion batteries in extreme cold. CATL has said its new battery works in temperatures as low as -40° Fahrenheit.
Also, a sodium-ion battery has much lower risk of fire. When lithium-ion batteries sustain damage, it can lead to “thermal runaway,” which triggers a dangerous and toxic fire.
The process of manufacturing sodium-ion batteries is similar to that of lithium-ion batteries, or at least similar enough that companies can shift existing assembly lines without having to spend heavily on retooling.
But sodium-ion batteries have some disadvantages. The big one is low energy density compared to lithium-ion. As a result, an EV running on a sodium-ion battery will go fewer miles per charge than a lithium-ion battery of the same size.
“That is just what nature has given us,” Srinivasan said. “From a physics perspective, sodium batteries inherently have lower energy density than lithium batteries.”
A typical sodium-ion battery has an energy density of about 150 watt-hours per kilogram at the cell level, he said. Lithium-ion batteries can range from about 180 to nearly 300 watt-hours per kilogram.
I asked Srinivasan what he makes of CATL’s claim of a sodium-ion battery with 200 watt-hours per kilogram.
“We tend to be skeptical of news releases from companies,” he said. He specified that his comment applies to all battery companies.