Batteries are finding their way into everything – from cars to heavy equipment to the electric grid. But scaling up production to meet the demands of a net-zero economy is complicated and contentious.  Season 4 of The Big Switch, a Columbia University podcast hosted by Dr. Melissa Lott, digs into the ways batteries are made and asks: what gets mined, traded, and consumed on the road to decarbonization? This is part one of “The Great Battery Boom,” a five-part series on global battery supply chains. Find the rest of Season 4 of The Big Switch on Apple podcasts, Spotify, or wherever you get your podcasts.