Ambri

Ambri is a Marlborough, Massachusetts-based energy storage company that develops and manufactures Liquid Metal™ battery systems for long-duration grid-scale energy storage. Founded in 2010 as the "Liquid Metal Battery Corporation" by MIT professor Donald Sadoway, PhD candidate David Bradwell, and Luis Ortiz - with seed funding from Bill Gates and French energy giant Total S.A. - the company's name is a nod to its origins in the heart of CAMBRIdge. Ambri's technology operates by using layers of molten metals as electrodes (calcium and antimony) and a molten salt electrolyte, all held liquid at operating temperature. Because every component is liquid, the battery self-assembles and has no mechanical degradation, enabling a lifespan of 20+ years with minimal capacity fade - a critical advantage over conventional lithium-ion systems.

Ambri's Liquid Metal™ batteries are engineered for 4-to-24-hour energy storage cycles, making them ideal for shifting daily renewable generation from solar and wind to periods of peak demand. Unlike lithium-ion systems, Ambri's batteries produce no gases, have no risk of thermal runaway, require no complex cooling or fire suppression infrastructure, and are built from readily available, fully recyclable materials. The modular, pre-fabricated 1-MWh system design enables rapid on-site deployment and scalable GWh-sized installations. The company achieved UL 1973 safety certification for its third-generation cells in 2023 and has deployed systems for notable customers including Microsoft and utility provider Xcel Energy.

Ambri is significant to the US energy supply chain as a domestic manufacturer of a novel, American-made long-duration storage technology that avoids the lithium and cobalt supply chain dependencies that constrain conventional battery manufacturers. By enabling utility-scale renewable energy projects to operate as dispatchable baseload power, Ambri's technology supports the broader national goal of grid decarbonization. In 2024, following financial difficulties, Ambri underwent a Chapter 11 restructuring and emerged recapitalized after its assets were acquired by a lender consortium comprising Gates Frontier, Paulson and Co., Fortistar, and other pre-bankruptcy investors. Co-founder David Bradwell was appointed CEO, and the company continues active development of its commercial battery systems.