Breakthrough Energy Ventures, helmed by Bill Gates, and MIT’s The Engine fund are leading an investment round of $20-million for Lilac Solutions, a US startup aimed at making the extraction of lithium less water-intensive and more sustainable. As the world looks to cut carbon emissions, people are increasingly turning to lithium-ion batteries for solutions such as powering electric vehicles or storing renewable energy. While there’s enough lithium available to meet today’s demand, BloombergNEF expects the market could see a shortfall as soon as 2023 as demand for the metal grows fourfold over the next decade.