Start-up Group1 seeks to commercialize potassium-ion batteries

The battery start-up Group1 has emerged from stealth with plans to commercialize a cathode material for potassium-ion batteries that could be an alternative to increasingly expensive lithium-based chemistries.

Lithium-ion batteries’ high energy density have made them the dominant choice for powering phones, laptops, and electric vehicles, but lithium prices have increased more than 300% over the past year, according to the research firm Benchmark Minerals.

Carmakers are already showing interest in cheaper cathode materials, such as lithium iron phosphate, which doesn’t contain nickel or cobalt like other types of lithium batteries. A number of companies are also trying to commercialize sodium-ion batteries as a way to reduce costs, even if it means sacrificing some energy density.

Group1 says its potassium Prussian white cathode material was invented by Leigang Xue, previously a postdoc in the University of Texas lab of lithium-ion battery pioneer John Goodenough. Xue is now the company’s chief product officer.

CEO Alex Girau, who previously founded the silicon anode company Advano, says the potassium material will help continue the cost-reduction trend. “Energy density is becoming less and less . . important,” he says.

The company also says that lithium mining won’t be able to keep up with the demand for batteries. Max Reid, a battery analyst with the consulting firm Wood Mackenzie, agrees that non-lithium batteries could help with the shortage of raw materials, especially when they are used for applications that don’t require high energy densities.

“Elements like potassium are bulkier and have less energy associated with them,” Reid says. “It just means that they won’t have as high a performance as lithium-ion. If you still get an [electric vehicle] with good range, it doesn’t really matter.”

Group1 plans to market the material primarily for use in heavy vehicles like delivery trucks or buses. Girau says potassium-ion batteries should charge faster than lithium-ion batteries, which could be make them attractive for carmakers as well.

The company says that, unlike sodium-ion cathode materials, its cathode material works with the graphite anodes used in lithium-ion batteries, simplifying integration into the existing battery manufacturing process. Group1 aims to boost production from kilograms to metric tons over the next 3 years.

Shirley Meng, a battery scientist at the University of Chicago, says Group1’s technology looks promising, noting that a key paper describing the technology behind the cathode material showed that it could achieve a high voltage. Still, she says potassium batteries’ lower energy density would probably make them more useful for stationary energy storage than for vehicle use.

Meng also cautions that it can take a decade to move from the lab to commercialization. “A battery is a very complex system,” she says. “You have to synchronize the anode, cathode electrolyte, the packaging, and the inactive materials.”