Meet the 33-year-old Canadian chemist and the renowned MIT professor who are building the ‘electric vehicle of cement making’
Leah Ellis and Yet-Ming Chiang
Photo courtesy The Engine
While Leah Ellis was earning her doctorate at Dalhousie University in Nova Scotia, she was part of a team that did battery research for Tesla. After she graduated, her budding career took an unusual turn.
“I could have gotten an easier job with my background in battery materials — a lot of my colleagues go work for Tesla or Apple. I could have done that, … and I would have made more money at first,” Ellis, 33, told CNBC by phone Wednesday.
Instead, Ellis applied for and won a prestigious Banting Postdoctoral Fellowship that granted her two years’ salary to work with whomever she wanted.
Ellis took her Ph.D. in electrochemistry and went to work for Yet-Ming Chiang, a renowned material sciences professor at Massachusetts Institute of Technology who is also a serial clean-tech entrepreneur. Chiang co-founded companies such as American Superconductor Corporation, A123 Systems, Desktop Metal, Form Energy and 24M Technologies.
Now Ellis is working to scale up a new climate-conscious process of making cement, one powered with electrochemistry instead of fossil fuel-powered heat.
Making cement using electrochemistry was Chiang’s idea, Ellis told CNBC in Boston at the end of May. Ellis said she worked with Chiang in 2018, just after he had started Form Energy, a long-duration battery company, and he was thinking about the abundant intermittent energy that was being generated by renewable energy sources such as wind.
“Sometimes people will pay you to take energy off their hands,” Ellis told CNBC. “Instead of putting that energy in a battery, what if we can use this extra low-cost renewable energy to make something that would otherwise be very carbon-intensive? And then the first on the list of things that are carbon-intensive — it’s cement.”
Cement is a necessary ingredient in concrete, which is the cornerstone of global construction and infrastructure, because it’s cheap, strong and durable. Four billion metric tons, which is the equivalent of 50,000 fully loaded airplanes, of cement is produced each year, according to a 2023 report from management consulting company McKinsey. The value of the market was $323 billion in 2021 and is expected to reach $459 billion by 2028, according to SkyQuest Technology Consulting.
Cement powder is conventionally made by crushing raw materials, including limestone and clay, mixing with ingredients such as iron and fly ash, and putting it all into a kiln that heats the ingredients up to about 2,700 degrees Fahrenheit. That process of making cement generates approximately 8% of global carbon dioxide emissions, which are a leading cause of global warming.
When Chiang had the idea to electrify cement manufacturing, he turned to Ellis. “He’s super busy, so he was like, ‘Go off and figure it out,'” Ellis told CNBC.
So she did.
In 2020, Ellis and Chiang co-founded Sublime Systems to refine and scale up the electrochemical process they created for making cement.
Sublime has raised $50 million from some leading clean-tech investors, including Chris Sacca’s LowerCarbon Capital and Boston-based, MIT spin-out venture firm The Engine; from Siam Cement Group, a leading cement and building materials company in Asia; and via a couple of grants from the U.S. Department of Energy’s Advanced Research Projects Agency-Energy, or ARPA-E, program.
Leah Ellis, CEO of Sublime Systems
Photo courtesy Summer Camerlo, Sublime Systems
Ellis likes to describe what they’re doing as developing the “electric vehicle of cement making.” An electric vehicle replaces a combustion engine with an electric motor, and that’s what Sublime Systems does in the cement-making process.
“I think for the layperson, it’s easiest for them to understand how we take that high-temperature, fossil-driven process and replace it with something that is powered by electrons. And we’re using electrons to push these chemical reactions,” Ellis told CNBC by phone Wednesday. “That happens at an ambient temperature below the boiling point of water,” she said, and that is a critical differentiator.
Ellis said she didn’t know much about cement when Chiang bade her to go figure out how to make low-carbon cement. She started by reading Wikipedia, and then textbooks. Then she worked with another Ph.D. student doing research that was later published in scientific journal articles on the topic. That led to the concept for what Sublime is doing now, and she’s continued to refine that concept ever since.
“And basically just haven’t stopped,” Ellis told CNBC. “It’s been five years.”
Bringing the ‘magic’ of chemistry to cement
Ellis has always been curious. “I grew up pretty nerdy, I guess, reading a lot of books,” she said. “I always had that thirst for knowledge and a sense of adventure.”
She also grew up in a religious household. Her father is an Orthodox Jewish rabbi from Texas, her mother grew up on a sheep farm in South Africa, and the two met when they were both in Israel. “Jerusalem has more than enough rabbis. So he moved to eastern Canada, where they don’t have a lot of rabbis,” Ellis told CNBC of her father’s move. Her family celebrated and encouraged having a robust intellectual life.
Leah Ellis, CEO of Sublime Systems, works in the cement lab.
Photo courtesy Leah Ellis
Ellis and one of her two younger sisters ended up getting their doctorates in chemistry.
“Both of us realize that chemistry is a very creative subject; it’s also a very difficult subject. And I think we both sort of gravitate to things that are challenging,” Ellis told CNBC.
When mastered, chemistry can be used to effect change. “It has a lot of creative power to make things happen in the real world,” Ellis said. “It’s almost like magic. If you work really hard on it, you can create things that make the world a better place.”
Battery scientists and cement producers have not historically worked together. “Cement typically sits in civil engineering, and battery science normally sits in chemistry or physics,” Ellis said. “They don’t go to the same conferences.”
But with Sublime Systems, Ellis and Chiang are bringing those two fields together.
That framework of using electrochemistry to drive reactions that once happened with very hot fossil fuel-powered reactions is not exclusive to cement.
“It’s a huge tool. I don’t think Sublime is the only one that’s applying electrochemistry to clean tech. I think the best way we have to get around fossil fuels is to use electrons,” Ellis told CNBC.
“The electrochemical way is often more efficient,” she said. “Heating things up to make them go is often not as efficient as electrochemistry, which is a bit more surgical, a bit more efficient — or at least can be more efficient with the right processes.”
That fundamental energy efficiency is why Chiang is confident in their solution.
“Decarbonizing cement production is going to be a very tough task. There will be numerous approaches, all of which have challenges and most of which deserve to be tested,” Chiang told CNBC. “I prefer to face our challenges because we see a pathway to complete decarbonization at cost parity with today’s cement while consuming the least amount of energy. In the long run, the lowest-energy process usually wins.”
Yet-Ming Chiang, professor of materials science and engineering at Massachusetts Institute of Technology, speaks during the 2016 IHS CERAWeek conference in Houston, Texas, Feb. 26, 2016.
Bloomberg | Bloomberg | Getty Images
The cement industry needs to clean up shop
“On the whole, the industry is highly motivated to go green,” Mark Mutter, the founder of Jamcem Consulting, an independent cement industry consultancy, told CNBC. Motivations to go green are highest for producers located in parts of the world such as Europe, where there is a price on carbon dioxide emissions at around 80 euros (almost $88) per metric ton. That’s “a big financial penalty for producers and it gives them an incentive to invest” in green cement tech, Mutter told CNBC.
That’s one reason investors are putting money behind Sublime.
“Customers are lining up to partner with Sublime because they can supply fossil-free cement at a time when the rest of the industry are all struggling to hit emissions targets and comply with carbon tariffs,” Clay Dumas, partner at LowerCarbon Capital, told CNBC.
“For Lowercarbon, their omnipresence and medieval production techniques are precisely the qualities that make building materials such an irresistible opportunity,” Dumas told CNBC.
Some cement producers are looking at carbon capture technologies as a way to manage their greenhouse gas emissions. But “this is highly costly, and in some respects is just business as usual and burying the problem for future generations,” Mutter told CNBC.
Sublime is making clean cement without the expensive additive of carbon capture and storage technologies, which is attractive because it keeps costs low, said Katie Rae, CEO at The Engine. “Producing decarbonized cement directly, rather than doing carbon capture, drives both energy efficiency and eventual cost parity,” Rae told CNBC.
Dumas said Sublime has “the most elegant chemistry, which runs on electricity at ambient temperatures while emitting zero carbon. That means they have no need for big ovens or costly CO2-capture systems that would drive up capex.”
Siam Cement Group looks at thousands of companies and makes only “a few” investments a year, Tim McCaffery, a venture investor at SCG, told CNBC. For SCG, what’s attractive about Sublime is that it avoids the complicated and expensive carbon capture technology and works with existing infrastructure.
“We have seen that Sublime Systems could disrupt the industry. The company produces a cement at room temperature that can drop into the existing ready mix supply chain and meets American Society for Testing and Materials standards,” McCaffery told CNBC. American Society for Testing and Materials is the body that creates test standards and protocols that manufacturers use to test their materials against.
Climbing stairs, making solutions, moving forward
Sublime completed its pilot plant at the end of 2022 and spent a few months on quality control measures. Now, Ellis is focused on getting the product to partners, and the company hopes to do its first construction project by the end of the year. The next step is to go from the 100-ton pilot plant to a 30,000-ton-per-year demonstration plant.
While Sublime is just getting ramped up, Ellis knows speed is essential in the race to decarbonize. “My mission is to have a swift and massive impact on climate change,” she told CNBC in Boston.
Leah Ellis bikes in Africa.
Photo courtesy Scott Carmichael
It’s an audacious goal, and while Ellis has credentialed chemistry chops, this is her first time being the boss of a company.
“I suppose I am aware of my age. And I’m also humble about that. I’m a first-time founder. I’m a first-time CEO,” Ellis told CNBC. “I figure things out as I do them. And I’m really lucky to have great mentors and support and people who believe in me, and, I think, who recognize the fact that I have a lot of energy, and I have a lot of passion. And I’m going to work as hard as I can for as long as I can to make this happen.”
Ellis knows how to keep herself going, too. She makes sure she gets good sleep and she stays active. She’s run seven marathons. She’s a cycler, and once cycled across Africa in about four months with a group, a trip that averaged out to riding more than 60 miles a day. She also participates in a “fitness cult” that climbs the Harvard stadium stairs every Sunday.
“I’m not a fast runner at all. I’m not a fast cyclist either,” Ellis told CNBC. “I just know how to toe that effort line to just like maintain the same effort for a very long time, and to keep my own spirits up.”
For Chiang, building solutions keeps him moving forward.
“It’s been about 15 years since the words ‘climate change’ entered the lexicon. It’s been a gift, and very energizing, to have potentially impactful solutions to pursue, as opposed to sitting and fretting,” Chiang told CNBC.
“I believe climate change has pushed all of us into an extremely fertile, creative period that will be looked back on as a true renaissance. After all, we’re trying to re-invent the technological tools of the industrial revolution. There’s no shortage of great problems to work on! And time is short.”
The logo for the Food and Drug Administration is seen ahead of a news conference on removing synthetic dyes from America’s food supply, at the Health and Human Services Headquarters in Washington, DC on April 22, 2025.
Nathan Posner | Anadolu | Getty Images
The U.S. Food and Drug Administration on Tuesday published a warning letter addressed to the wrist wearable company Whoop, alleging it is marketing a new blood pressure feature without proper approvals.
The letter centers around Whoop’s Blood Pressure Insights (BPI) feature, which the company introduced alongside its latest hardware launch in May.
Whoop said its BPI feature uses blood pressure information to offer performance and wellness insights that inform consumers and improve athletic performance.
But the FDA said Tuesday that Whoop’s BPI feature is intended to diagnose, cure, treat or prevent disease — a key distinction that would reclassify the wellness tracker as a “medical device” that has to undergo a rigorous testing and approval processes.
“Providing blood pressure estimation is not a low-risk function,” the FDA said in the letter. “An erroneously low or high blood pressure reading can have significant consequences for the user.”
A Whoop spokesperson said the company’s system offers only a single daily estimated range and midpoint, which distinguishes it from medical blood pressure devices used for diagnosis or management of high blood pressure.
Whoop users who purchase the $359 “Whoop Life” subscription tier can use the BPI feature to get daily insights about their blood pressure, including estimated systolic and diastolic ranges, according to the company.
Whoop also requires users to log three traditional cuff-readings to act as a baseline in order to unlock the BPI feature.
Additionally, the spokesperson said the BPI data is not unlike other wellness metrics that the company deals with. Just as heart rate variability and respiratory rate can have medical uses, the spokesperson said, they are permitted in a wellness context too.
“We believe the agency is overstepping its authority in this case by attempting to regulate a non-medical wellness feature as a medical device,” the Whoop spokesperson said.
High blood pressure, also called hypertension, is the number one risk factor for heart attacks, strokes and other types of cardiovascular disease, according to Dr. Ian Kronish, an internist and co-director of Columbia University’s Hypertension Center.
Kronish told CNBC that wearables like Whoop are a big emerging topic of conversation among hypertension experts, in part because there’s “concern that these devices are not yet proven to be accurate.”
If patients don’t get accurate blood pressure readings, they can’t make informed decisions about the care they need.
At the same time, Kronish said wearables like Whoop present a “big opportunity” for patients to take more control over their health, and that many professionals are excited to work with these tools.
Understandably, it can be confusing for consumers to navigate. Kronish encouraged patients to talk with their doctor about how they should use wearables like Whoop.
“It’s really great to hear that the FDA is getting more involved around informing consumers,” Kronish said.
FILE PHOTO: The headquarters of the U.S. Food and Drug Administration (FDA) is seen in Silver Spring, Maryland November 4, 2009.
Jason Reed | Reuters
Whoop is not the only wearable manufacturer that’s exploring blood pressure monitoring.
Omron and Garmin both offer medical blood pressure monitoring with on-demand readings that fall under FDA regulation. Samsung also offers blood-pressure-reading technology, but it is not available in the U.S. market.
Apple has also been teasing a blood pressure sensor for its watches, but has not been able to deliver. In 2024, the tech giant received FDA approval for its sleep apnea detection feature.
Whoop has previously received FDA clearance for its ECG feature, which is used to record and analyze a heart’s electrical activity to detect potential irregularities in rhythm. But when it comes to blood pressure, Whoop believes the FDA’s perspective is antiquated.
“We do not believe blood pressure should be considered any more or less sensitive than other physiological metrics like heart rate and respiratory rate,” a spokesperson said. “It appears that the FDA’s concerns may stem from outdated assumptions about blood pressure being strictly a clinical domain and inherently associated with a medical diagnosis.”
The FDA said Whoop could be subject to regulatory actions like seizure, injunction, and civil money penalties if it fails to address the violations that the agency identified in its letter.
Whoop has 15 business days to respond with steps the company has taken to address the violations, as well as how it will prevent similar issues from happening again.
“Even accounting for BPI’s disclaimers, they do not change this conclusion, because they are insufficient to outweigh the fact that the product is, by design, intended to provide a blood pressure estimation that is inherently associated with the diagnosis of a disease or condition,” the FDA said.
WATCH: Watch CNBC’s full interview with FDA commissioner Dr. Marty Makary
United Launch Alliance Atlas V rocket carrying the first two demonstration satellites for Amazon’s Project Kuiper broadband internet constellation stands ready for launch on pad 41 at Cape Canaveral Space Force Station on October 5, 2023 in Cape Canaveral, Florida, United States.
Paul Hennessey | Anadolu Agency | Getty Images
As Amazon chases SpaceX in the internet satellite market, the e-commerce and computing giant is now counting on Elon Musk’s rival company to get its next batch of devices into space.
On Wednesday, weather permitting, 24 Kuiper satellites will hitch a ride on one of SpaceX’s Falcon 9 rockets from a launchpad on Florida’s Space Coast. A 27-minute launch window for the mission, dubbed “KF-01,” opens at 2:18 a.m. ET.
The launch will be livestreamed on X, the social media platform also owned by Musk.
The mission marks an unusual alliance. SpaceX’s Starlink is currently the dominant provider of low earth orbit satellite internet, with a constellation of roughly 8,000 satellites and about 5 million customers worldwide.
Amazon launched Project Kuiper in 2019 with an aim to provide broadband internet from a constellation of more than 3,000 satellites. The company is working under a tight deadline imposed by the Federal Communications Commission that requires it to have about 1,600 satellites in orbit by the end of July 2026.
Amazon’s first two Kuiper launches came in April and June, sending 27 satellites each time aboard rockets supplied by United Launch Alliance.
Assuming Wednesday’s launch is a success, Amazon will have a total of 78 satellites in orbit. In order to meet the FCC’s tight deadline, Amazon needs to rapidly manufacture and deploy satellites, securing a hefty amount of capacity from rocket providers. Kuiper has booked up to 83 launches, including three rides with SpaceX.
Space has emerged as a battleground between Musk and Amazon founder Jeff Bezos, two of the world’s richest men. Aside from Kuiper, Bezos also competes with Musk via his rocket company Blue Origin.
Blue Origin in January sent up its massive New Glenn rocket for the first time, which is intended to rival SpaceX’s reusable Falcon 9 rockets. While Blue Origin currently trails SpaceX, Bezos last year predicted his latest venture will one day be bigger than Amazon, which he started in 1994.
Kuiper has become one of Amazon’s biggest bets, with more than $10 billion earmarked for the project. The company may need to spend as much as $23 billion to build its full constellation, analysts at Bank of America wrote in a note to clients last week. That figure doesn’t include the cost of building terminals, which consumers will use to connect to the service.
The analysts estimate Amazon is spending $150 million per launch this year, while satellite production costs are projected to total $1.1 billion by the fourth quarter.
Amazon is going after a market that’s expected to grow to at least $40 billion by 2030, the analysts wrote, citing estimates by Boston Consulting Group. The firm estimated that Amazon could generate $7.1 billion in sales from Kuiper by 2032 if it claims 30% of the market.
“With Starlink’s solid early growth, our estimates could be conservative,” the analysts wrote.
WATCH: Amazon launches first Kuiper internet satellites into space
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