A materials company in Alameda, California, has spent the last decade working to boost the energy stored in lithium-ion batteries, an advance that could enable smaller gadgets and electric vehicles with far greater range.
Sila has developed silicon-based particles that can replace the graphite in anodes and hold more of the lithium ions that carry the current in a battery.
Now the company is delivering its product to the market for the first time, providing a portion of the anode powder in the battery of the forthcoming Whoop 4.0, a fitness wearable. It’s a small device but potentially a big step forward for the battery field, where promising lab results often fail to translate to commercial success.
“Think of the Whoop 4.0 as our Tesla Roadster,” says Gene Berdichevsky, Sila’s CEO, who as Tesla’s seventh employee helped solve some of the critical battery challenges for the company’s first electric vehicle. “It’s really the first device on the market that’s proving this breakthrough.”
The company’s materials, with a light assist from other advances, increased the energy density in the fitness tracker’s battery by around 17%. That’s a significant gain in a field that generally inches forward by a few percentage points a year.
It’s equivalent to about four years of standard progress, “but in one big jump,” says Venkat Viswanathan, an associate professor of mechanical engineering at Carnegie Mellon University.
Sila still faces some real technical challenges, but the advance is a promising sign for the potential of increasingly capable batteries to help the world shift away from fossil fuels as the dangers of climate change accelerate. Boosting the amount of energy that batteries can store makes it easier for increasingly clean electricity sources to power more of our buildings, vehicles, factories, and businesses.
For the transportation sector, a more energy-dense battery can reduce the costs or extend the range of electric vehicles, addressing two of the biggest issues that have discouraged consumers from giving up their gas guzzlers. It also promises to deliver grid batteries that can save up more energy from solar and wind farms, or consumer gadgets that last longer between charges.
Energy density is the key to the “electrification of everything,” says Berdichevsky, an Innovator Under 35 in 2017.
In the case of the new fitness wearable, the novel battery materials and other improvements made it possible for Boston-based Whoop to shrink the device by 33% while maintaining five days of battery life. The product is now thin enough to be inserted into “smart apparel” as well as being worn like a watch. It goes on sale September 8.
Sila, which announced $590 million in funding in January, also has partnerships in place to develop battery materials for automakers including BMW and Daimler. The company has said its technology could eventually pack as much as 40% more energy into lithium-ion batteries.
Berdichevsky interviewed for and landed his job at Tesla before his senior year at Stanford University, where he was working toward a degree in mechanical engineering. He ended up playing a key role in addressing a potentially existential risk for the company: that a fire in any one of the thousands of batteries packed into a vehicle would ignite the whole pack.
He set up a program to systematically evaluate a series of battery pack designs. After hundreds of tests, the company developed a combination of battery arrangements, heat transfer materials, and cooling channels that largely prevented runaway fires.
After Tesla launched the Roadster, Berdichevsky felt he had to either commit to another five years to see the company through development of the next vehicle, the Model S—or take the opportunity to try something new.
In the end, he decided he wanted to build something of his own.
Berdichevsky went back to Stanford for a master’s program studying materials, thermodynamics, and physics, in the hope of finding ways to improve storage at the fundamental level. After graduating, he spent a year as an entrepreneur in residence at Sutter Hill Ventures, looking for ideas that could form the basis of his own business.
During that time, he came across a scientific paper identifying a method to produce silicon-based particles for lithium-ion battery anodes.
Researchers have long seen silicon as a promising way to increase the energy in batteries, because its atoms can bond with 10 times more lithium ions by weight than graphite can. That means they hold far more of the charged molecules that produce the electric current in a battery. But silicon anodes tended to crumble during charging, as they swelled to accommodate the ions that shuttle back and forth between the electrodes.
The paper, coauthored by Georgia Institute of Technology professor Gleb Yushin, highlighted the possibility of developing rigid silicon materials with a porous core that could more easily accept and release the lithium ions.
The next year, Berdichevsky cofounded Sila with Yushin and Alex Jacobs, another former Tesla engineer.
Hurdles and delays
The company spent the next decade tweaking its methods and materials, working through more than 50,000 iterations of the chemistry while scaling up its manufacturing capacity. Early on, it decided to develop drop-in materials that manufacturers of lithium-ion batteries could swap in, rather than pursuing the more expensive and riskier route of producing complete batteries itself.
Sila is not as far along as it had initially hoped to be, however.
After securing several million dollars from the US Department of Energy’s ARPA-E division, the company at one point told the research agency its materials could be in products by 2017 and in vehicles by 2020. In 2018, when Sila announced its deal with BMW, it said its particles could help power the German automaker’s EVs by 2023.
Berdichevsky says the company now expects to be in vehicles by “more like 2025.” He says that solving the “last mile” problems was simply harder than they expected. Challenges included working with battery manufacturers to get the best performance out of the novel materials.
“We were naïvely optimistic about the challenges of scaling and bringing products to market,” he said in an email.
The Whoop news signals that Sila was able to engineer the particles in a way that offers safety, life cycles, and other battery performance benchmarks similar to those achieved in existing products.
Donald ’67, SM ’69, and Glenda Mattes
Don Mattes started giving to the Picower Institute for Learning and Memory at MIT before he himself was diagnosed with Alzheimer’s disease. Since his death in 2020, his wife, Glenda, has carried forward Don’s passion for its work. “My wish is that no one ever has to go through the horrors of Alzheimer’s disease ever again,” Glenda says. The Matteses have also supported the Koch Institute for Integrative Cancer Research at MIT.
Legacy sparks hope. An early key employee of Andover Controls who later ran the company’s European operations, Don visited six continents with Glenda during their 30-year marriage—often to ski or bicycle. “Don’s was a life well lived, just too short,” Glenda says. The couple made provisions in their estate plan to support the Picower Institute. After Don died, Glenda made a gift to MIT of real estate that established both endowed and current-use funds there to support research on Alzheimer’s, dementia, and other neurodegenerative diseases. Glenda is a cancer survivor, and the gift also endowed a fund in the couple’s name at the Koch Institute.
Great discoveries being made at MIT: “Don always said the best thing he got from MIT was being taught how to think,” Glenda says. “MIT is an amazing place. Picower Institute director Li-Huei Tsai and her team are doing more than looking for a treatment for Alzheimer’s. They’re looking for the root cause of the disease. I am also fascinated with the Koch’s melding of engineering and biology. The chances they are going to solve the cancer issue someday are very high.”
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Investing in women pays off
“Starting a business is a privilege,” says Burton O’Toole, who worked at various startups before launching and later selling AdMass, her own marketing technology company. The company gave her access to the HearstLab program in 2016, but she soon discovered that she preferred the investment aspect and became a vice president at HearstLab a year later. “To empower some of the smartest women to do what they love is great,” she says. But in addition to rooting for women, Burton O’Toole loves the work because it’s a great market opportunity.
“Research shows female-led teams see two and a half times higher returns compared to male-led teams,” she says, adding that women and people of color tend to build more diverse teams and therefore benefit from varied viewpoints and perspectives. She also explains that companies with women on their founding teams are likely to get acquired or go public sooner. “Despite results like this, just 2.3% of venture capital funding goes to teams founded by women. It’s still amazing to me that more investors aren’t taking this data more seriously,” she says.
Burton O’Toole—who earned a BS from Duke in 2007 before getting an MS and PhD from MIT, all in mechanical engineering—has been a “data nerd” since she can remember. In high school she wanted to become an actuary. “Ten years ago, I never could have imagined this work; I like the idea of doing something in 10 more years I couldn’t imagine now,” she says.
When starting a business, Burton O’Toole says, “women tend to want all their ducks in a row before they act. They say, ‘I’ll do it when I get this promotion, have enough money, finish this project.’ But there’s only one good way. Make the jump.”
Preparing for disasters, before it’s too late
All too often, the work of developing global disaster and climate resiliency happens when disaster—such as a hurricane, earthquake, or tsunami—has already ravaged entire cities and torn communities apart. But Elizabeth Petheo, MBA ’14, says that recently her work has been focused on preparedness.
It’s hard to get attention for preparedness efforts, explains Petheo, a principal at Miyamoto International, an engineering and disaster risk reduction consulting firm. “You can always get a lot of attention when there’s a disaster event, but at that point it’s too late,” she adds.
Petheo leads the firm’s projects and partnerships in the Asia-Pacific region and advises globally on international development and humanitarian assistance. She also works on preparedness in the Asia-Pacific region with the United States Agency for International Development.
“We’re doing programming on the engagement of the private sector in disaster risk management in Indonesia, which is a very disaster-prone country,” she says. “Smaller and medium-sized businesses are important contributors to job creation and economic development. When they go down, the impact on lives, livelihoods, and the community’s ability to respond and recover effectively is extreme. We work to strengthen their own understanding of their risk and that of their surrounding community, lead them through an action-planning process to build resilience, and link that with larger policy initiatives at the national level.”
Petheo came to MIT with international leadership experience, having managed high-profile global development and risk mitigation initiatives at the World Bank in Washington, DC, as well as with US government agencies and international organizations leading major global humanitarian responses and teams in Sri Lanka and Haiti. But she says her time at Sloan helped her become prepared for this next phase in her career. “Sloan was the experience that put all the pieces together,” she says.
Petheo has maintained strong connections with MIT. In 2018, she received the Margaret L.A. MacVicar ’65, ScD ’67, Award in recognition of her role starting and leading the MIT Sloan Club in Washington, DC, and her work as an inaugural member of the Graduate Alumni Council (GAC). She is also a member of the Friends of the MIT Priscilla King Gray Public Service Center.
“I believe deeply in the power and impact of the Institute’s work and people,” she says. “The moment I graduated, my thought process was, ‘How can I give back, and how can I continue to strengthen the experience of those who will come after me?’”