Inside Clean Energy: Solid-State Batteries for EVs Make a Leap Toward Mass Production

Colorado-based Solid Power has begun rolling out batteries that will enable electric cars to run much longer on a charge. Meanwhile, Houston researchers announced progress on a solid-state battery for energy storage.

Yan Yao (left) and Ye Zhang work with solid-state sodium batteries.Credit: University of Houston
University of Houston researchers Yan Yao (left) and Ye Zhang work with solid-state sodium batteries. Credit: University of Houston

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At some point, the development of solid-state batteries—in which electrons flow through a solid material instead of a liquid or gel—is going to lead to electric vehicles that can go much farther on a charge and battery-storage systems that can hold more energy while taking up less space. We just don’t know when that is going to be.

But in the last 10 days, two announcements offer reasons to think the answer is “sooner rather than later.”

First, Solid Power, a Colorado-based company developing solid-state EV batteries for partners including Ford and BMW, said it has completed installation of a “pilot production line” that is capable of making about 300 battery cells per week. This signals that the technology is now moving from the lab to the factory.

Second, University of Houston researchers published a paper showing how they have developed a glasslike material that is highly effective as an electrolyte—the part of a battery that electrons pass through during cycles of charging and discharging—for use in a sodium-sulfur battery for energy storage. The research is notable because this is a solid-state battery, and because it shows the promise of sodium-sulfur batteries as an alternative to lithium-ion batteries for long-duration energy storage.


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Let’s step back for some solid-state battery 101. I reached out to George Crabtree, director of the Joint Center for Energy Storage Research, which is based at Argonne National Laboratory near Chicago, to help explain why these batteries are special.

“I would say, first of all, that solid-state batteries are very likely to be the next big thing at the commercial level,” he said. 

They would be the biggest step forward in battery technology since 1991, he said. That was when Sony released the first commercial lithium-ion battery.

Solid-state batteries are capable of holding much more energy per unit of mass than today’s lithium-ion batteries, which means an EV could go for much longer before needing to be recharged, he said. Even though the electrolyte is solid, it is porous on a microscopic level, allowing electrons to pass through it.

Researchers have long known that a solid-state design has advantages over batteries that use a liquid or gel, including lithium-ion batteries. One of the big advantages is that solid electrolytes can be made to weigh less and take up less space than liquids or gels. But there are some big engineering challenges that have slowed this technology from reaching consumers. 

Solid-State Batteries

One issue is dendrites, the spiky fibers that can accumulate in a battery during recharging, diminishing the battery’s performance. Dendrites aren’t alive, even though they sometimes resemble branches of a tree, or even clumps of wild mushrooms. They are a problem for many kinds of batteries, including lithium-ion, and have been especially vexing for researchers designing solid-state batteries. The new solid-state designs have a variety of approaches to dealing with the problem, including the use of an electrolyte that resists or otherwise limits the growth of dendrites.

Researchers have developed solid electrolytes made of ceramics, glass and mixes of ceramics and glass.

Solid Power, based in Louisville, Colorado, is a spinoff from research begun at the University of Colorado Boulder. It was founded in 2011 and is now publicly traded with a market capitalization of $1.3 billion. The company’s battery uses a ceramic-glass electrolyte. 

With its partners Ford and BMW, Solid Power is one of the leading players in the race to develop a mass-market electric vehicle that runs on a solid-state battery system.

Among the major competitors is QuantumScape of San Jose, California, which has a market capitalization of $5.1 billion and is working with Volkswagen.

Just about every automaker is developing solid-state batteries, either with an external partner like Solid Power or QuantumScape, or through internal research and development.

By announcing its new production line, Solid Power is indicating that it is on track to produce its systems on a much larger scale by the mid-2020s.

“With the EV cell pilot line now installed, our next big challenge is commencing production at scale and building cells that meet the requirements necessary for us to enter into automotive qualification later this year,” Derek Johnson, chief operating officer at Solid Power, said in a statement.

A solid-state battery cell is being produced on Solid Power's new production line. Credit: Chet Strange/Solid Power
A solid-state battery cell is being produced on Solid Power’s new production line. Credit: Chet Strange/Solid Power

He is referring to the years-long process of working with automakers to validate the safety and effectiveness of the systems before the batteries can be sold to the public.

In addition to improving the performance of EVs, solid-state batteries could be part of a new generation of energy-storage systems.

The University of Houston research results, published in the journal Nature Communications, show the results of a project to develop a solid-state battery for use in grid-scale energy storage.

Researchers say their battery is low cost, easy to build, has a high degree of mechanical stability and is chemically stable—four important factors for viability in the market. 

“To date, no single sodium solid electrolyte has been able to achieve all four of these requirements at the same time,” Yan Yao, an electrical and computer engineering professor and co-author of the paper, said in a statement.

The key component is the glasslike electrolyte that uniquely combines the properties of oxygen and sulfur, Yao said in an email. It also resists dendrite formation.

His team is trying to develop a battery that has the potential to combine low costs and an ability to discharge for up to 12 hours on a single charge. The key to the low costs is that one of its main materials, sodium, is widely available and affordable, in contrast to lithium.

I asked Crabtree how these recent developments in research and manufacturing fit into the bigger picture of the transition to clean energy.

“Lithium-ion is the best battery we’ve ever had,” he said. “However, it can’t do everything.”

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Lithium-ion batteries have been highly effective for the current generation of EVs but are not well-suited for long-haul ground vehicles, rail, ships or aircraft. Lithium-ion batteries also are not well-suited for grid-scale energy storage of more than four hours.

Much of current battery research is looking at what materials and designs are going to be most effective for these other applications, he said. The development of solid-state batteries is a small part of this larger picture.

So solid-state batteries can make EVs and energy storage systems capable of holding more energy than today’s batteries, but that’s just the beginning of something bigger and transformative for the energy economy.

Other stories about the energy transition to take note of this week:

Biden Pauses Solar Tariffs and Uses Defense Production Act to Boost the Renewable Energy Sector: The solar industry has been reeling in recent months because of uncertainty related to an U.S. investigation of whether solar panel manufacturers illegally dodged tariffs on panels from China. The Biden Administration sought to sidestep the problem this week by announcing a two-year pause on new solar tariffs, which should help to reopen the flow of solar equipment from the countries including Vietnam that were part of the investigation, as Ana Swanson, David Gelles and Jim Tankersley report for The New York Times. Biden also invoked the Defense Production Act to boost the supply of solar panels, heat pumps, insulation and other essential products of the clean energy economy, as Adam Aton reports for E&E News. The inclusion of heat pumps and insulation are notable because they show the Biden Administration taking actions to help reduce emissions from buildings. “The importance of this cannot be understated,” Ari Matusiak, CEO of Rewiring America, a nonprofit that advocates for electrifying the U.S. economy, said to E&E News. “It’s a big move by the administration.”

U.S. Solar Industry Sees Worst Quarter Since 2020: The Biden Administration took its actions in response to escalating complaints that the government’s investigation was severely harming the solar industry. And this wasn’t empty talk, based on figures released this week showing that U.S. solar installations in the first quarter were down 24 percent compared to the first quarter of 2021, the worst showing in a quarter since 2020. The report was released by the Solar Energy Industries Association based on data from the research firm Wood Mackenzie. “The solar industry is facing multiple challenges that are slowing America’s clean energy progress, but this week’s action from the Biden administration provides a jolt of certainty businesses need to keep projects moving and create jobs,” said Abigail Ross Hopper, SEIA’s president and CEO, in a news release.

Century-Old ​‘District Energy’ Networks Can Help Decarbonize Cities: A plan being pursued by Vicinity Energy would help to convert the district steam system serving parts of Boston and Cambridge to run partially on electric-power boilers and heat pumps. The project, which would use electricity to help reduce the use of natural gas in the system, could help to show a path for reducing emissions in district heating systems in other cities and on college campuses, as Jeff St. John reports for Canary Media. “We can become a converter of electric renewable power to steam, and our customers don’t have to do a damn thing,” said Bill DiCroce, Vicinity’s CEO.

Tesla Owners Love Their Cars—but Elon Musk, Not so Much: Tesla owners purchase the company’s cars, and frequently the stock, because they care about the environment and adore the way the vehicles drive and look. But their adoration has been complicated by the behavior of Tesla CEO Elon Musk, as Karen Heller writes for The Washington Post. “I find him deeply problematic,” said Lindsey Banning of Dayton, Ohio, a Tesla owner and a clinical psychologist. “He is an attention-seeking person.” Another Tesla owner, Andy Slye of Louisville, said, “I chose to view Elon Musk as this separate character aside from Tesla, a blessing and a curse.”

A New GOP Climate Plan Is Long on Fossil Fuels, Short on Specifics: Republicans in Congress chose to hold the first public event for their new climate plan in the country’s No. 1 oil-producing county, in New Mexico, and before an audience of people who work in the oil industry. As you might guess, this is a plan that involves producing much more oil and gas and it was immediately pilloried by environmental advocates and Democrats, as I reported for ICN. The plan consists of six bullet points without much detail. While Democrats are unlikely to get behind a proposal to increase oil and gas production, there are parts of the framework that have broad support, like encouraging growth in U.S. manufacturing and streamlining the permit process for energy projects like transmission lines.

Inside Clean Energy is ICN’s weekly bulletin of news and analysis about the energy transition. Send news tips and questions to