Form Energy has raised $750 million in a Series G round to expand manufacturing capacity in West Virginia, adding to investor interest in long-duration energy storage as AI-linked data center growth lifts U.S. power demand. The company develops iron-air batteries that can supply electricity for up to 100 hours by converting iron to rust during discharge and reversing the process when recharged, a chemistry it says can cut costs by relying on iron instead of lithium, cobalt and nickel. Form has previously said the latest financing brings its total funding to more than $2 billion and that the money will help scale output and support early commercial deployments, including projects involving Xcel Energy and Google. The company has also lined up other customers including Crusoe and FuturEnergy Ireland, while its commercial backlog has grown to about 80 gigawatt-hours, the Wall Street Journal reported, roughly four times earlier this year. The latest raise comes as the U.S. installed 9.7 gigawatt-hours of energy storage in the first quarter, up 32% from 2025, and as renewable energy is expected to make up more than 90% of new U.S. generating capacity this year.