Down a steep dirt road from the Baishi Huashan lithium mine in southern China, trucks laden with silvery grey ore rumble towards a cluster of smelters in the valley below that have sprung up to cash in on the electric vehicle battery boom. The city of Yichun, China's most prospective region for lithium, is ground zero in the country's push to cut its reliance on imports of the metal for its battery industry, which makes three-quarters of the world's lithium-ion batteries. Mining the metal from a rock called lepidolite, Yichun aims to quadruple its output to about 350,000 metri...