"Tesla plans to use Glencore cobalt in new Gigafactories", 16 June 2020.

Tesla plans to use cobalt from Anglo-Swiss mining giant Glencore to build lithium-ion batteries at its new factories, according to industry sources...Glencore, which is the largest industrial supplier of cobalt in the world, could provide Tesla with up to 6,000 tons of cobalt a year under the long-term partnership...The cobalt will come from the Democratic Republic of the Congo, where Glencore has been operating a copper mine in the Katanga region since 2008 that produces it as a byproduct...

Tesla defended its cobalt sourcing in a company report. “Because Tesla recognizes the higher risks of human rights issues within cobalt supply chains, particularly for child labor in the Democratic Republic of Congo (DRC), we have made a significant effort to establish processes to remove these risks from our supply chain,” the report reads...the extraction of cobalt has been plagued by concerns around illegal mining, human rights violations and corruption. The cobalt producing mines in the DRC have been under scrutiny for years now...researchers found that cobalt miners are being exposed to dangerously high levels of toxic pollution that is causing birth defects in their children...Tesla is currently being sued along with Apple, Google, Microsoft and Dell for the deaths and injuries of child miners in the DRC, which is one of the poorest countries in the world...