General Motors‘ venture capital arm will lead a $50 million Series B funding round into Energy Exploration Technologies Inc., known as EnergyX, a startup that specializes in lithium extraction technology, the companies said Tuesday.

GM Ventures will lead the round and also reached a strategic agreement with EnergyX to develop the company’s lithium extraction and refinery technology, the companies said.

EnergyX is the latest in a series of investments and supply agreements between GM and companies that specialize in battery raw materials, processing, cell production and recycling as the automaker transitions to a fully electric vehicle lineup. In January, for instance, GM said it will take a $650 million equity position in Lithium Americas Corp. and work with the company to jointly develop Nevada’s Thacker Pass lithium mine.

“We are committed to securing EV critical minerals that are sustainable and cost competitive to maintain our leadership position among automakers,” Jeff Morrison, GM’s vice president of global purchasing and supply chain, said in a statement. “The investment in EnergyX is further proof point of GM’s leadership position.”

Privately held EnergyX is one of several companies developing so far unproven direct lithium extraction technologies that could help GM filter the metal for its Ultium battery packs from some types of brine that have been largely ignored by the mining industry in favor of evaporation ponds and open-pit mines.

Brine deposits are essentially salt-infused waters found throughout the globe. Many teem with lithium, calcium and other minerals, and direct extraction technologies aim to separate out the lithium and leave the rest.

GM, which declined to say how much of the Series B round it was funding, will have the right of first refusal to buy lithium from any projects that EnergyX develops.

The deal includes strategic funding for other lithium production projects in North and South America, the companies said.

EnergyX has said its technology can make lithium metal directly from brine, a tantalizing prospect for GM that could let the automaker bypass lithium refining, which is widely seen as a key supply chain bottleneck.

EnergyX CEO Teague Egan said in a statement that a shortage of lithium is the largest roadblock to advancing production of electric vehicles.

“We will unlock lithium supply in the U.S., a pivotal move in expanding the EV industry,” Egan said. “There are many ways of gauging success, but few are more rewarding than the support of leaders like GM.”

EnergyX is building five demonstration facilities that it plans to locate in Argentina, Chile, and in the U.S. states of California, Arkansas and Utah. Potential customers would supply brine from acreage that they own in order to test EnergyX’s technology, before signing any development deal.

The sites selected in the United States are near existing lithium brine reserves owned by Standard Lithium Ltd., Compass Minerals International Inc. and CTR, each of whom has selected a DLE technology provider but not yet launched production.

Automotive News Staff Reporter Lindsay VanHulle and Reuters contributed to this report.