What type of battery, using abundant metals like iron, began manufacturing at scale by Form Energy in 2025 for multi-day energy storage?

The battery technology that began manufacturing at scale by Form Energy in 2025 for multi-day energy storage is the iron-air battery. This innovative solution leverages the readily available and inexpensive metals like iron, along with water and air, to store and discharge electricity for extended periods, addressing a critical need in the transition to a more reliable and clean electric grid.

The core principle behind iron-air batteries is a reversible rusting process. During discharge, the battery "breathes in" oxygen, causing iron metal to rust and release energy. When charging, an electrical current reverses this reaction, converting the rust back into iron and releasing oxygen. This simple yet effective chemistry allows for significantly longer discharge durations compared to traditional lithium-ion batteries, which typically offer only a few hours of storage. Form Energy's iron-air batteries are designed to store energy for up to 100 hours, making them ideal for managing the intermittency of renewable energy sources like wind and solar, ensuring power is available even during prolonged periods without sunshine or wind.

Beyond their multi-day storage capability, these batteries offer several compelling advantages. The use of abundant, non-toxic, and non-flammable materials like iron, water, and air makes them a safer and more environmentally sustainable option than some other battery chemistries. This also translates to lower manufacturing and operational costs, positioning iron-air batteries as a cost-effective solution for large-scale grid stabilization. Form Energy's first high-volume manufacturing facility in Weirton, West Virginia, aims to produce these next-generation battery systems, contributing to grid resilience and supporting the integration of renewable energy.