SEOUL, Sept 4 (Reuters) - South Korea's SK On said on

Thursday it has signed a deal with U.S.-based Flatiron Energy

Development to supply lithium iron phosphate (LFP) batteries for

energy storage systems (ESS).

SK On, which supplies automakers including Hyundai Motor ( HYMLF )

, Kia Corp ( KIMTF ) and Ford Motor ( F ), said it

will supply up to 7.2 gigawatt hours (GWh) of ESS batteries

between 2026 and 2030, marking its first order for LFP batteries

to use in energy storage systems.

The company did not disclose the value of the contract.

SK On said in a statement that it will begin mass production

of ESS-dedicated LFP batteries in the second half of next year,

adding that it plans to convert some of its electric vehicle

(EV) battery production lines in Georgia for ESS use.

"The LFP battery production for energy storage systems

expects to further strengthen our product lineup and business

portfolio and to effectively respond to the temporary slowdown

in electric vehicle demand, and accelerate stable growth," the

company said in a statement.

It said that it also planned to establish LFP production

in South Korea.

SK On's deal echoes a trend among EV battery makers of

expanding into energy storage as a hedge against slow EV demand.

In July,

LG Energy Solution

warned that U.S. tariffs and the scheduled end

of federal EV purchase subsidies by September 30 may weigh on EV

demand into early 2026, prompting it to ramp up ESS production,

while cutting or delaying investment plans.