liquid metal battery

Robert Llewellyn from the Fully Charged show interviewed Prof Donald Sadoway from MIT and the Ambri battery company using their liquid metals battery technology. Almost all batteries today are lithium-ion. LiOn is good for mobility but is overkill for stationary batteries states Sadoway. Ambri is designed for large scale, with no mobility and at room temperature. Liquid metal batteries (at 500oC) provide cheaper and more effective firming for the grid and for business applications.


  • Other companies are developing other liquid metal designs
  • The Calcium-Antimony is patented.
  • During development calcium replaced the original magnesium anode.
  • Liquid salt batteries store thermal heat in concentrated solar and other technologies and should not be confused with liquid metal
  • Different technology metal air batteries are described in another post.

Liquid Metals Battery Design

Sadoway’s liquid metal battery is three liquid layers of different densities. He compares the separation as what oil and vinegar do in a salad dressing. The densest, a molten antimony cathode, is on the bottom, the light calcium alloy anode is on top, and the intermediate-density calcium chloride salt electrolyte sits in the middle.

  • Calcium & antimony electrodes
  • Calcium-chloride salt electrolyte
  • Commercial grade materials
  • Calcium is the 5th most abundant element in Earth’s crust website details design

Benefits and Features.

  • Costs $180/kWh to $250/kWh depending on size and duration. The projected cost by 2030 is ~ $21/kWh
  • No fire risk with no combustible materials
  • No membranes.
  • The batteries operate at extremely high temperatures (500oC)
  • Modular – about 2MWh per 40′ container
  • Cabled in series so reduced cabling expense
  • Self-heating and insulated, requiring no external heating or cooling.
  • Lifespan of more than 20 years
  • Maintain 99% of their capacity
  • Round trip is 80% efficient
  • Over 5,000 charging cycles, 4 years
  • Scaleable to GW size – connect containers
  • Daisy chain power connectors – can be in parallel or serial
  • Cheap raw materials
  • Unlike aqueous redox flow batteries, needs no pumps
  • Unlike LiOn batteries does not need cooling or heating systems to keep < 50oC
liquid metals battery chemistry

Commercial Progress

  • Sadoway cofounded Ambri to develop a commercial product in 2010 with patents and with financial support from Bill Gates.
  • LMBC (liquid metals battery corporation) raised $15m in 2012
  • The first installation is for a Microsoft data center in Nevada for a data centre on a 3,700-acre property. This battery will store energy from a co-located 500 MW renewable generation. It appears to be a 250MWh battery.
  • Ambri secured $144M in capital led by Reliance New Energy Solar (Reliance Industries), Paulson & Co., Bill Gates, Fortistar, Goehring & Rozencwajg and Japan Energy Fund to accelerate growth and build domestic manufacturing facility
  • Six 1M installs with commercial partners
  • Aiming for 2025 fully commercial
  • Production 12 GW pa factory
  • Sustainable and profitable.

Supply of Antimony

Nearly 90 per cent of the world’s antimony today comes from China. Other countries have reserves. However, since 2013, China has limited exports. During 2019, China moved from being a net supplier of antimony to an importer, sending prices soaring. In August 2021, Ambri signed a supply agreement with Perpetua Resources in Idaho, one of the few U.S. producers of antimony. Perpetua is focused on gold but antimony is in that project. Antimony is now on the critical metals lists in all major regions including Canada, UK, US and Europe. (

Other Metal Batteries

  • Pellion Technologies – Lithium Metal
  • NantEnergy – Zinc-Air uses zinc but also has a fully recyclable aluminum-air battery
  • Phinergy – Aluminium-Air
  • E-stone – Iron-Air. Dutch based E-stone
  • Form Energy – US based Frame Energy has iron air products in pilot or early deployment.

Further Reading

Ted Talk 2011