Germany is advancing salt-and-air (iron-air) battery technology designed to store renewable energy for weeks or even decades without using lithium, cobalt, or rare earth metals. Instead, the system relies on abundant materials like iron, salt, and air, making it cheaper, safer, and more sustainable for grid-scale storage. These batteries are not meant for phones or cars—they are designed for long-duration energy storage, solving one of the biggest challenges of solar and wind power: storing elec