The Fisker Automotive Karma, which looks like it will be the first plug-in hybrid sold in the United States, could be powered by lithium ion batteries from Enerdel, based in Indianapolis.

The two companies have signed a letter of intent for a supply contract, pending the results of reliability and performance testing, according to a press release from Enerdel. The battery maker also announced the opening of “the first commercial-scale production line for automotive-grade lithium-ion batteries in the U.S.” The plant is in Indiana.

Enerdel uses lithium manganese oxide electrodes, the same type used in the batteries selected for GM’s Volt plug-in hybrid. It was developed at Argonne National Laboratory with support from the U.S. Advanced Battery Consortium (comprising Ford, GM, and Chrysler).

Fisker had originally said that it would use batteries from Advanced Lithium Power, based in Vancouver, BC.

Plug-in hybrids use large battery packs that can be recharged by plugging them in, reducing gasoline consumption far more than ordinary hybrids, which can’t be plugged in.