Every time an EV battery reaches the end of its life, there's still nickel and cobalt inside it — metals that once had to be dug out of Indonesia and Congo, the two most expensive and most geopolitically fraught metals in a battery. This business grinds old batteries into a “black powder” (black mass), then dissolves it in acid to pull the nickel and cobalt back out as pure “sulfate” that can feed a new battery plant directly. This is the story of the “urban mine,” battery edition — set to become the second supply line for this metal pair, and a shortcut that helps the West stop relying on mines in just a few countries.