Mine more nickel https://www.theverge.com/2020/9/22/21451670/tesla-cobalt-free-cathodes-mining-battery-nickel-ev-cost
"Musk urged mining companies to dig up more nickel
during a July earnings call and did so again during Battery Day. “In order to scale, we really need to make sure that we’re not constrained by total nickel availability. I actually spoke with the CEOs of the biggest mining company in the world and said, ‘Please make more nickel, it’s very important,” Musk said today."