As auto manufactures scramble to secure supplies of critical minerals needed for electric vehicles, General Motors chief executive officer Mary Barra said her company has secured the minerals it needs to to build 400,000 electric vehicles this year and in 2023, and to get to 2 million battery-powered cars a year by 2025. That’s when GM will be ramping up production of about 30 electric models globally.

“There’s tremendous work that has gone on, it’s been going on for well over a year,” Barra said on GM’s first-quarter earnings call with analysts. “We’ll continue to announce things not when we start working on things, but when we have signed agreements. This will be a continued competitive advantage for GM.”

Booming sales of electric vehicles have quadrupled the price of lithium and led to questions about supply, Bloomberg reported. Tesla Inc. CEO Elon Musk made a public appeal for more investment in lithium mining to close what he sees as a yawning gap between supply and demand from the adoption of electric vehicles. He tweeted that he may have to get into mining.

In her letter to shareholders, Barra said GM started early by building long-term relationships in North America and finding stable trading partners like Australia. Those include suppliers of rare earth materials, lithium, as well as a new cobalt agreement. She said GM is still working to secure adequate nickel supplies.