In a recycling facility in Covington, Georgia, workers grind up dead batteries into a fine, dark powder. In the past, the factory shipped that powder, known in the battery recycling industry as black mass, overseas to refineries that extracted valuable metals like cobalt and nickel. But now it keeps the black mass on site and processes it to produce lithium carbonate, a critical ingredient for making new batteries to power electric vehicles and store energy on the grid. From Nevada to Arkansas,...