A Beautiful Pitch, A Harsh Reality

I still remember the first time I saw Ambri’s pitch. An incredibly dapper salesman walked on stage and said: “The wind doesn’t always blow, and the sun doesn’t always shine, and that’s why alternative energy needs grid-scale energy storage.”

I was captivated. They nailed it. That moment is why I chose to work in grid-scale energy storage, because I too wanted to fight climate change.

Fast forward ten+ years and I’ve become an incredibly specialized battery scientist. At one point I even had a near-miss with Ambri, someone inside suggested I apply after seeing my resume. But the portal asked for my ideal salary, so I added $25k on top of my market rate. Why? Because that’s the money it would take to lure me away from the love of my life: lithium-ion.

Turns out the market agreed. Lithium-ion has not only held its turf, but also expanded into the grid market that Ambri once claimed as its destiny. Let’s get into it.

Ambri 101: Who They Were (RIP 🪦)

• Origin Story: Spun out of Donald Sadoway’s lab at MIT.
  

• Technology: Liquid metal batteries: calcium–antimony or magnesium–antimony layers separated by molten salt.

  • Three fluid layers (metal anode, molten salt electrolyte, metal cathode) that self-separate by density under high temperature, Sadoway compared it to oil and vinegar self-separating

  • Ambri’s IP portfolio can be found here.
    

• Market Pitch: Cheap, safe, and long-lived grid batteries made from earth-abundant materials.
  

• Value Promise: Long duration (4–24 h) storage, minimal capacity fade, safety (no volatile liquid organics), and cost that could undercut lithium-ion in grid storage.
  

• Positioning: Ambri cast itself not as a marginal player, but as a potential enabler of “24/7 renewables.”

The Market Need They Identified

Ambri was right, the intermittency problem is real:

• Solar only works when the sun does.
  

• Wind is spectacularly fickle.
  

• Grids need multi-hour storage to time-shift renewables, replace fossil peaker plants, and smooth frequency.
  

This is why the grid-scale battery market is already booming. Ambri’s insight was correct: storage is the bridge that makes renewable energy feasible and competitive.

The High Temperature Hype

Ambri’s story had all the startup glitter:

• Bill Gates, Khosla Ventures, and TotalEnergies wrote big checks.
  

• MIT pedigree, media love, endless think pieces about “post-lithium breakthroughs.”
  

• Promises of projects in Hawaii, India, and Microsoft’s backyard.
  

• PR headlines practically crowned them the lithium killer.

  • “Ambri Secures $144 Million Financing” (PR Newswire, August 2021). Ambri announced a major funding round led by Reliance, Bill Gates, Paulson & Co. The release emphasized that funds would fuel commercialization, manufacturing scale, and deployment. 

  • “Ambri Deploys Liquid Metal Battery System for Microsoft” (Business Wire, September 2022). They announced the successful commissioning of a system for Microsoft’s datacenter, casting it as a milestone in their pathway to commercialization.

  • “Liquid-Metal Battery Will Be on the Grid Next Year” (IEEE Spectrum, August 2023).

    • “Ambri’s grid battery costs $180/kWh to $250/kWh depending on size and duration, the company says. But its projected cost is about $21/kWh by 2030, according to a paper Sadoway and colleagues published in October 2021.”

The industry was ready to believe, because everyone wanted a hero to dethrone lithium-ion. Plus Bill Gates!

Another One Bites the Dust in the Commercialization Valley of Death

Ambri’s autopsy isn’t about lack of vision; it’s about brutal engineering realities.

• Thermal Overstress: The batteries had to live at ~500°C (or more). That’s energy you constantly spend just maintaining temperature, insulation challenges, safety risks. Utilities don’t want to babysit a furnace.
  

• Corrosion Fatigue: Molten metals chew through containers, seals, and current collectors. Good luck guaranteeing a 20-year service life.
  

• Economic Short Circuit: “Cheap materials” don’t equate to a cheap system. Balance-of-plant killed the economics. 

  • Even if the cell works, the system-level cost (balance of system, thermal management, controls, maintenance) proved high. Lithium-ion cost decline outpaced expectations, making Ambri’s “cheap metal” argument weaker over time.

• Scaling Gap/ Valley of Death: Going from lab cell to MW-scale plant is like jumping from baking cookies in your kitchen to running Nabisco.

  • Lab to MW-scale to utility-grade plant is a huge leap. You have to handle manufacturing, QA, reliability, supply chains, certifications. Ambri seemed to struggle to bridge that.

• Market Timing & Competitive Pressure: While Ambri was iterating, lithium-ion cell factories were scaling, costs were plummeting, and grid operators became more comfortable with boring but proven solutions. The window of opportunity shrank.

• Overpromising / Milestone Slippage: Some of their PR promised big field deployments or certifications by dates that slipped. Over time, that erodes credibility with investors, utilities, integrators.

Death Spiral Timeline

• 2010–2013: 🔥Big vision, big checks, big PR. Founded out of MIT. Early press calls it the “post-lithium” solution. Big checks from Gates, Khosla, and Total.

• 2014–2017: 📉Commercialization dates slip. Pilot projects announced, but no real deployments.

• 2018–2020: 🧊Media interest cools. Lithium-ion prices nosedive, eating Ambri’s supposed cost advantage.

• 2021: 💸$144M raise makes headlines

• 2022: 🔋PR blitz: Microsoft demo project, UL certification news. Still no widespread deployments.

• 2023: 🔌Utility partnerships announced (Xcel Energy), IEEE Spectrum feature pumps optimism. Meanwhile, commercialization window shrinks.

• 2024: 💀Ambri files Chapter 11. Later acquired/restructured in a quieter comeback attempt.

• 2025: 🪦Officially folds this month. The auction is here

Lessons Learned

Ambri’s failure is a perfect case study so that the industry does not keep failing over and over again in the same way.

• The pain point was real. Ambri’s pitch was dead on. Storage is essential for renewables.
  

• Execution is harder than vision. Scaling molten metal was a nightmare. Sexy chemistries have much harder problems than run of the mill easy solutions. And easy to manufacture is the trump card for commercialization.
  

• Boring beats exotic. Lithium-ion wasn’t novel, but it was available, bankable, and cheap. In batteries, boring wins. Exotic is exciting until it burns through your runway.

The Legacy of Ambri

Ambri stands as a reminder of how brutally hard it is to take a bold lab idea into the messy, cost-driven world of the grid. Their pitch was right. The need was real. But the tech and timing didn’t line up.

The story of Ambri shows that sometimes, even when you identify the right market and the right problem, execution is everything. Lithium-ion: boring, well-understood, and relentlessly scalable, stole the show.

Still, Ambri’s research pushed the boundaries, inspired engineers, and proved that the energy transition needs more than hype:  it needs chemistry that can actually scale. In that sense, Ambri’s molten dream wasn’t wasted. It set the stage for the next round of contenders in grid storage.

Some Resources We Love :

• MIT made this great Ambri paper open access just to remind everyone they are the GOAT