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 Nov. 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 U.S. 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 U.S. 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 degrees 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.

I asked Srinivasan how sodium-ion batteries fit into this larger picture. He said sodium-ion will likely gain market share over the next few years as an alternative to lithium-ion batteries.

Near the end of the decade, solid-state batteries will begin to become available, which would allow for higher energy densities and longer driving ranges. Solid-state batteries use a solid electrolyte instead of a liquid or gel. The electrolyte is the substance through which ions move as they go from side to side during charging and discharging.

The technologies can coexist in the market, Srinivasan said.

He thinks solid-state batteries will initially be most common in high-end models and popular with people who want the longest possible ranges.

He expects that sodium-ion batteries will be more common in low-cost EVs for people who live in cities or suburbs and don’t place a high premium on driving range.

“It will not be a fringe player,” he said, about sodium-ion. “It will actually be a fast-growing segment.”