Nothing can stop the proliferation of iPhones, solar panels, and Teslas—except, perhaps, a shortage of key natural resources. The prices of “technology minerals” such as cobalt (up 75% this year) and lithium (up 20%) crucial to making, say, batteries for electric cars, have spiked recently. That could just be the beginning. In March, an international team of researchers, led by Saleem Ali, a professor of energy and environment at the University of Delaware, published a paper warning of possible shortfalls in supply of the metals. Adding to the challenge for Silicon Valley: Deposits of these minerals are largely concentrated outside the U.S.