David Snydacker knew going in that California’s Imperial Valley was a “graveyard for lithium-extraction technologies.”

For years, companies had tried and failed to find a cost-effective way to pull the valuable mineral — a key ingredient in the batteries that power electric cars — from the naturally heated fluid deep beneath the Salton Sea. One of the most recent busts was Simbol Materials, a much-hyped startup that collapsed in 2015 shortly after Elon Musk’s Tesla Inc. offered to buy the firm for $325 million.