Tesla has  said it plans to expand the use of cheaper, iron-based batteries to a version of its Semi heavy electric trucks  as well as in an affordable electric vehicle.

Tesla chief executive Elon Musk has championed the lithium iron phosphate (LFP) battery technology dominated by Chinese suppliers, saying in March,  that the vast majority of the heavy lifting for electrification will be done by iron-based cells.”

However, having Chinese suppliers build battery factories in the Unites States is a challenge because of the current  U.S.-China political tensions.

The world’s biggest electric carmaker said in its paper on “Master Plan Part 3″released last week that it will use LFP batteries for “short-range” heavy electric trucks, which it calls “Semi Light,” without providing details, such as a launch date.

Last DecemberTesla started to deliver its Semi electric trucks with a claimed longer, 800km driving range per charge using nickel-based batteries. Tesla previously said it will also launch a 600-km range version.

The automaker said its proposed small electric passenger cars will use LFP batteries with capacity of 53 kilowatt-hours (kWh), versus 75 kWh for Model Y and Model 3.

Tesla said last month that it will cut assembly costs by half in future generations of cars, which will be built at its factories in Mexico and elsewhere, saying it will also use LFP batteries in its mid-sized vehicles, Model 3 and Model Y, without giving a timeline.

Currently, Tesla uses nickel-based batteries for most of its Model 3 and Model Y vehicles sold in the United States.

Musk and other LFP advocates cited the abundance and cheaper prices of iron as a key factor outweighing the drawbacks that have held back the adoption of LFP cells globally. They are bigger and heavier, and generally hold less energy than nickel-based cells, giving them a shorter range.