SAN FRANCISCO, June 10 (Reuters) - General Motors ( GM ) may scrap plans to use a lower-cost, iron-based battery chemistry that many automakers are using to cut electric-vehicle costs, GM's head of battery technology said. 

The Detroit automaker had said it planned to develop lithium-iron phosphate, or LFP, batteries for use in future EV models, and would begin making those batteries in late 2027 at a jointly owned plant in Tennessee.

But GM battery chief Kurt Kelty told Reuters that GM instead is focused on developing a different battery chemistry, lithium manganese-rich, or LMR, which the company has said costs about the same as LFP to make in the U.S., but can store more energy for the same weight and size. 

Kelty said GM may no longer pursue LFP for use in EVs. He said the Tennessee factory will start production this month of LFP cells, but those are for energy storage systems.

"There is a possibility where LFP does not earn its way into our portfolio," Kelty said following a GM event in San Francisco on Tuesday, calling LMR the "workhorse" for GM. "That's where we're going to be using the big volume," he said.

GM has been working on LMR for over a decade. Its crosstown rival, Ford Motor ( F ), last year said it was working to scale LMR chemistry for use in future EVs. 

Despite the chemistry's advantages, including reducing reliance on critical minerals, technical challenges such as the battery weakening with use mean mass adoption is not expected anytime soon, S&P Global said last year.

RIVALS EMBRACE LFP CHEMISTRY

Bypassing LFP would mark a significant departure from the battery strategies of many of GM's competitors.  

Chinese carmakers pioneered the use of the lower-cost LFP chemistry, which is less dense - resulting in shorter driving ranges - but also cheaper and considered safer and more durable than the nickel-rich batteries used by many U.S. and European automakers.

Many global automakers, including Tesla,  Rivian and Ford Motor ( F ), have added LFP-based EVs to cut costs and offer more-affordable electric options as demand for battery-powered cars slows in the U.S.

GM has released more than a dozen U.S. EVs over the past few years, all using a more powerful nickel-rich chemistry. But its recently launched Chevrolet Bolt, its least expensive EV for the U.S. market, uses LFP cells from Chinese battery giant CATL, Reuters and other media outlets have reported.

GM said last year its goal was to start commercial production of LMR cells at a U.S. facility in 2028. Kelty did not confirm if that date is still the goal, but said LMR "is on schedule with development."