The Race Is on to Build a Better Battery

Renewable energy could reshape the global economy—but only if it can be cheaply and safely stored. Meet the companies racing to crack the anode code.
At the Amprius factory in Wuxi, China, workers operate a machine that winds together anodes and cathodes to make batteries. May 2019. Photograph by Stephen Chow
Photograph by Stephen Chow
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At first glance, all seems serene on a spring morning at the research-and-development campus of SK Innovation, one of Korea’s biggest industrial conglomerates. The campus sits in Daejeon, a tidy, planned city an hour’s high-speed-train ride south of Seoul that the national government has built up as a technology hub. Dotting SK’s rolling acres are tastefully modern glass-and-steel buildings that wouldn’t be out of place in a glossy architecture magazine. One contains a library, its tables stocked with rolls of butcher paper and Post-it notes to spur creativity. Another houses an espresso bar where engineers queue for caffeination. A cool breeze blows. Birds chirp. Pink cherry blossoms bloom.

Then Jaeyoun Hwang, who directs business strategy for SK’s R&D operation, steers the Kia electric car in which he is driving me around the campus to a stop at the top of a hill. In front of us looms K-8, a seven-story-tall cube of a building sheathed in matte silver siding and devoid of any visible windows. Its only discernible marking is, at the top corner of one wall, a stylized orange outline of a familiar object: a battery. K-8 appears whimsical, almost a bauble, until Hwang explains that four other buildings on the campus, plus another one under construction, also are for battery research—an activity at SK that employs several hundred people and counting. When I ask to go inside K-8 for a look, Hwang says it’s out of the question. When I raise my camera to take a picture, he stops me. “In this area,” he says, “photographs of the buildings are prohibited.”

SK has a sprawling R&D campus because it has a storied technological pedigree—as Korea’s oldest oil refiner. Now the petrochemical company is hitching its future to electric cars. It has inked deals to make batteries for some of the world’s largest automakers, notably Volkswagen AG, which, following a crippling scandal in which it was found to have deliberately and repeatedly violated pollution rules in producing its diesel vehicles, has pledged a green corporate rebirth, shifting much of its lineup to cars that run on electricity rather than oil. SK has made huge deals with VW and other automakers, including Daimler AG, which says it will sell 10 pure-electric car models by 2022, and Beijing Automotive Group, or BAIC Group, China’s largest maker of pure-electric cars. SK is racing to build massive battery plants in China, Europe, and the United States, including one an hour’s drive from Atlanta. It is moving by 2025 to balloon its battery production, mulling investing some $10 billion in the effort over that span. That’s a serious number even for a behemoth that in its various corporate incarnations, has spent more than a half-century processing black gold sucked from the ground. “These days,” Hwang says of SK’s battery business, “the order volume is huge.”

GLOBAL PLAYER: CEO Kang Sun has helped Amprius raise money from both American and Chinese backers.Photograph by Christie Hemm Klok for Fortune
Photograph by Christie Hemm Klok

For years, the race to build a better battery was contained to consumer electronics. It was a growing business, but it wasn’t going to reorder capitalism. Now, amid an onslaught of electric cars on the road and renewable electricity on the power grid, the race is gearing up into a corporate and geopolitical death match. It suddenly has the dead-serious attention of many of the planet’s biggest multinationals, particularly auto giants, oil majors, and power producers. Having historically dismissed affordable energy storage as a pipe dream, they now view it as an existential threat—one that, if they don’t harness it, could disintermediate them. It also divides the world’s major economic powers, which see dominance of energy storage in the 21st century as akin to control of coal in the 19th century and of oil in the 20th. One clear sign: Battery-technology competition is deeply woven into the ongoing trade tensions between the U.S. and China.

For more about the battery industry, read “Baking a ‘Jellyroll’: How Batteries Are Made.”

Even Jeffrey Chamberlain, a battery geek, finds today’s shift breathtaking. For years he worked at Argonne National Laboratory, heading one of the U.S. government’s top battery-research efforts. Now he leads a Chicago-based venture-capital fund, Volta Energy Technologies, that takes money from nervous power, oil, and other companies and invests it in energy-storage-technology startups. The corporations have concluded they have to hedge their bets, Chamberlain says, because “what renewable energy represents to these companies is massive destruction.” China, meanwhile, has declared a world-leading battery industry a strategic national priority, doling out incentives to get the job done. “What does that imply?” Chamberlain asks. “Are they the new Saudi Arabia of batteries?”

Unprecedented billions of dollars are pouring into battery research and development, rendering batteries today the sort of technological target that semiconductors were a generation ago. A particularly fast stream is flowing into startups, each promising more brashly than the next to have cracked the code on the energy-storing black box. That money is coming from multinationals scrambling for technological fixes, from venture-capital firms looking for the next big home run, and from sundry billionaires who say they want to save the planet. And it’s coming from both sides of the Pacific.

Some startups will win big; many more will implode. Either way, they are the leading edge of the battery race—the pack in which the jostling is most cutthroat, the daring is most on display, and the long-term breakthroughs are most likely to develop. They’re also more talkative than the big players about what they’re doing; that stands to reason because they’re hungrier for investment.

Today’s global battery race has two main heats. One, already well underway, is for batteries for electric cars, whose market value the energy-data firm Wood Mackenzie projects will jump to $41 billion in 2024, from $13 billion in 2017. This is the market that has prompted Elon Musk’s Tesla to build a massive battery plant—what Tesla calls a “gigafactory”—in Nevada. This is the market that’s pushing essentially every global automaker—embarrassed by Tesla in the electric-car market and adamant not to be embarrassed anymore—to lob massive orders at SK and other major battery producers, almost all headquartered in Asia. It’s also inducing them to invest in startups promising technological leaps.

The other heat, just beginning, is for batteries for the electric grid: factory-size devices designed to store massive amounts of energy, potentially for days or weeks at a time. Such technology could enable an epic transition from fossil fuels, such as coal and natural gas, which are altering the climate but can be fired on or off at will, to the sun and the wind, which are clean but don’t always shine or blow. The market for them remains nascent and largely dependent on government subsidies—which is to say that it’s risky and anyone’s to win. A swashbuckling band of technologists, bankrolled by deep-pocketed investors from a Bill Gates–backed fund to Saudi Aramco, are gunning to get their long-term energy-storage devices to market first.

At stake in both heats is more than the fate of some entrepreneurs and their speculative backers. At stake is the future of the global economy. Ever since Benjamin Franklin flew a key on a kite in a lightning storm, electricity has proved difficult to store in large quantities. That’s why cars still run on oil, which can be stored easily in tanks. It’s why transmission lines still are required to transport electricity hundreds or thousands of miles from where it’s generated to where it’s consumed. And it’s why the vast majority of electricity still is produced by burning fossil fuels, which, for all their environmental downsides, are ruthlessly reliable. Flick a switch, the system springs to life, and the lights go on.

If electricity could be stored in large amounts at low cost, radical changes could follow. The electric car, which has fewer parts than a petroleum-powered vehicle and thus, at scale, should be cheaper to manufacture, could eclipse the internal-combustion engine. Sunlight could be stored as electricity during the day, and wind power at night, and renewable energy could, at acceptable cost, be made to behave like a constant, rather than as an intermittent, energy source. Given that transportation and electricity together account for about 40% of global greenhouse-gas emissions, humanity’s carbon output—which scientists warn will have to crater essentially to zero by mid-century to avoid particularly dangerous climate change—actually might start plummeting.

A grand reordering of economic winners and losers likely would result, with established players scrambling for new business models. Automakers would have to retool or die. Oil companies would have to reinvent themselves at least in significant part as renewable-energy providers or shrivel into oblivion. Utilities would have to pivot to a new and decentralized business in which they operated huge numbers of solar panels and wind turbines and batteries. Figuring out how to store electricity economically, in other words, could short-circuit the global economy and then rewire it.

Can it be done? I burned a lot of fossil fuel this spring trying to find out. I drove around Northern California and flew around the world. In Silicon Valley, Boston, China, and Korea, I found startups clawing their way up and corporations struggling not to fall down. All were nervous, though some were more forthcoming about that than others. Energy storage today is the mother of all frothy markets.

The battery is, in its basic architecture, a simple device. It contains four main parts: a positively charged electrode, called a cathode; a negatively charged electrode, called an anode; a substance that connects them, called an electrolyte, which typically is a liquid; and a membrane, known as a separator, that prevents certain particles from traveling from one electrode to the other in a “short circuit,” which could spark a fire. A too-thin separator was implicated in a rash of fires in 2016 in some Samsung phones.

When a battery is powering a device, chemical reactions inside it break atoms into positively charged particles, called ions, and negatively charged particles, called electrons. The ions and electrons move simultaneously from the anode to the cathode, but they move in different streams. The ions move through the battery; the electrons create a circuit through the device, powering it.

In a conventional battery, when all its ions and electrons have moved from the anode to the cathode, the battery is dead. A rechargeable battery can be plugged in to receive new electricity, positioning ions and electrons in the anode to power the device again.

MANO A NANO: An Amprius machine that applies gases to metal to produce “silicon-nanowire” anodes.Photograph by Christie Hemm Klok for Fortune
Photograph by Christie Hemm Klok for Fortune

A major goal in battery research is maximizing “energy density”: the amount of energy that can be shoved into a battery of a given volume or weight. That depends largely on the number of ions its anode can hold; the more ions, the more electrons the battery will have available to keep the device running. This primacy of ions and anode frames two crucial realities of today’s battery quest.

One is that virtually all batteries today get their ions from the same element: lithium. Lithium is a particularly “light” element, which means its ions are particularly small, which means a particularly large number of them can be stuffed into an anode. So most electric devices today, from iPhones to Teslas, are powered by “lithium-ion” batteries.

The other reality is that a crucial part of today’s battery quest is the bid to build a better anode: one that can accommodate especially massive quantities of lithium ions.

Among the many hopefuls trying to perfect a super-anode is Amprius, a decade-old startup with headquarters in Silicon Valley, most of its operations in China, and investors in both countries that collectively have pumped about $140 million into the company. They include Trident Capital and Kleiner Perkins, two Silicon Valley venture capital firms; SAIF Partners, a Chinese private-equity firm; and the Wuxi Industry Development Group, a government-owned investment company in Wuxi, the Chinese city in which Amprius has a sizable battery factory. Unlike many startups, Amprius is already producing batteries and selling them to prominent customers. Amprius had about $50 million in revenue last year, says Kang Sun, the company’s chief executive. But its technology remains buggy, and its future is hardly assured. “We’re not out of the woods yet,” he says.

Sun is a tech-industry lifer. He favors coiffed hair, pressed shirts, and straight talk. He grew up in China, earned a Ph.D. at Brown, worked his way up to vice president at Honeywell, and then went back to China to help build JA Solar, now one of the world’s largest solar-panel makers. Today he lives near San Francisco, drives a Tesla, and flies seemingly constantly around the world.

His current gig as head of a transpacific battery startup is, he says, “the most difficult job I’ve had in my life.” Over the hours I spent with him, one phrase kept popping out of his mouth, muttered almost subconsciously, as if a mantra: “not easy.” As in: “Battery technology is not easy.”

The source of his lament: the maddening elusiveness of the super-anode.

The anodes in most lithium-ion batteries are made of graphite, a substance that’s cheap and plentiful. Amprius, like many other startups, is trying to make anodes from silicon, which, gram for gram, theoretically can hold 10 times as many lithium ions as graphite can. “Theoretically” is a colossal caveat. Silicon’s upside as a lithium-ion hoarder has a major downside too: When silicon is stuffed with lots of lithium ions, it swells. That swelling can crack the anode material, dramatically shortening a supposed super-battery’s life.

More than a decade ago, a Stanford materials-science professor, Yi Cui, developed a new technique to avert silicon swelling in an anode. It uses a structure of silicon that, at nanoscale, resembles a single bristle of an upturned brush. Lab experiments proved that, as each is stuffed with lithium ions, it has plenty of space to swell without knocking into another bristle and cracking the anode. Amprius is the company created to commercialize the concept, known as “silicon nanowire.”

Sun soon signed on as CEO, figuring he’d spend a few years building Amprius and then flip it or take it public at a handsome profit. A decade later, he’s still on the hot seat. “We have to scale up 30 times bigger,” he says. “Otherwise, we cannot make money.”

Amprius’s intellectual hub, in Sunnyvale, Calif., the heart of Silicon Valley, is a bunker-like suite in an unremarkable industrial park. The walls are scuffed, the furniture looks rented even though it isn’t, and one day when I visit, the floor under the men’s-room urinals is lined with cardboard sheets pocked with stains. This summer, Amprius is moving to a different office; it’s moving because its lease wasn’t renewed, but it will pay lower rent. Money at Amprius isn’t spent on creature comforts. It’s spent on science and manufacturing.

In a lab of the Sunnyvale office is Amprius’s crown jewel: a room-sized machine, designed by Amprius and built in Europe to its specifications, that applies a mix of silane gas and other gases to a metal substrate; the resulting chemical reaction creates the silicon nanowires. Visible through a peephole in the machine about the diameter of a silver dollar, the gas-application process is a purple haze. Everything about it is intricate and finicky: the composition of the gases; the pressure and temperature at which they’re shot in; the speed at which the substrate moves along the conveyor belt inside the machine.

Once the anode material comes out of the machine, in a double-sided roll that’s battleship gray, it packs about 200,000 silicon nanowires per square centimeter per side. It’s cut and sent into a series of small lab rooms, where workers in white coats and blue surgical masks assemble batteries essentially by hand. Amprius says the best of these batteries have an energy density about 60% higher than that of conventional lithium-ion batteries. One downside is that they don’t withstand as many discharges and charges as conventional batteries—something Amprius is working to improve.

Amprius’s cutting-edge batteries have piqued the interest of the U.S. Army, which is testing them for use in clothing that soldiers might wear to power the devices they use in the field. By far the batteries’ biggest buyer is Airbus. As part of a program dubbed Zephyr, Airbus is testing them on unmanned planes known as high-altitude pseudo-satellites, or HAPS. Last December, the two companies announced that one of the Airbus vehicles powered by Amprius batteries flew for more than 25 days, “setting a new endurance and altitude record for stratospheric flight.”

To Sun, the Airbus contract is both a lifeline and a yellow flag. “We charge them a crazy price” for the batteries, he says. “That kind of price is not sustainable.” The batteries crafted in Sunnyvale, in other words, are akin to suits sewn on Savile Row: bespoke, expensive, and therefore at risk. “If it cannot scale up,” Sun says of the California operation, “it will die.”

Shipping containers and wind turbine at Vionx
HEAVY METAL Shipping containers holding a Vionx “flow” battery that stores electricity produced by this wind turbine in Worcester, Mass.Photograph by Jesse Burke for Fortune
Photograph by Jesse Burke

Airbus has compelling reasons to pay Amprius’s price. It is trying to outpace its rivals, including Boeing, in developing and commercializing both a less-expensive alternative to satellites and a viable fleet of electric-powered air taxis. “There are hundreds of startups out there” claiming they have the next big thing in batteries, says Mark Cousin, chief executive of A3 by Airbus, an innovation center the company has set up in Sunnyvale, not far from Amprius. But, other than Amprius, “we’ve not seen any evidence that any of the companies are close to having something that could potentially be mature enough to be integrated into a product in the short to medium term.”

In China, meanwhile, Amprius is chasing a broader market. In Nanjing, the southern Chinese metropolis in which Sun grew up, Amprius has another laboratory where it’s developing an anode material less rarefied than its silicon-nanowire technology but still more advanced than the industry norm. It’s a nanoscale structure of silicon manufactured as a powder and then combined with traditional graphite powder. The resulting graphite-silicon mixture is run through a conventional battery plant. This modest silicon boost typically raises a battery’s energy density by up to 15% beyond a traditional lithium-ion battery’s. That’s far less than the improvement from the silicon-nanowire material, but it’s radically cheaper.

On the morning I visit Nanjing, dozens of bags of the silicon powder are stacked on a metal shelf. To my untrained eye, they resemble ground coffee, differing only in their shade of brown. Some evoke French roast; others, a lighter blend. Amprius is supplying the material to various U.S., European, Japanese, Korean, and Chinese automakers for testing. It also trucks the powder to a factory in nearby Wuxi that was built for Amprius in 2016.

When I visit the Wuxi factory, it’s cranking out batteries for children’s smartwatches and for consumer battery packs. The factory also makes batteries for a Chinese dronemaker. Chuanxin Zhai, a scientist there who has been dispatched to walk me around, says he’s particularly proud the factory won a recent contract for the watch batteries. It did so after an intense competition over energy density with Amperex Technology Ltd., or ATL, a Chinese company that’s one of the biggest battery makers in the world. Zhai mentions another customer for which the Wuxi factory has made batteries: a firm that uses them to make cold-weather oxygen-­supply machines. That firm, he says, sells the machines to the Chinese military, for medical use in Tibet.

That hints at the sensitivities facing many battery companies with footprints in both the U.S. and China. Amid tensions between the two countries, Sun says, Amprius has to be careful about whom it accepts as investors and customers. He’s a U.S. citizen and says he prefers American living. But commerce is commerce: Amprius is just finishing a $30 million fundraising round, and all of that money is coming from Chinese investors. The market for batteries, Sun explains, “is a Chinese business.” His adopted country, he tells me, “needs to wake up.”

Like Sun, David Vieau is a tech-industry veteran with decade spent trying to build a battery company. Unlike Sun, Vieau (he pronounces it “View”) has experienced the bitterness of defeat.

In 2012, A123 Systems, the lithium-ion company Vieau helped create, filed for bankruptcy, a stunning fall. Since its founding a decade earlier, A123 had raised $350 million in private capital, spent $129 million in matching-grant funds from U.S. taxpayers, and earned about $390 million in a much-ballyhooed 2009 IPO.

A123 had built factories on the assumption it would win contracts to supply batteries for electric cars from GM and other automakers, only to see those companies drastically dial back production plans. An A123 recall of certain batteries didn’t help. In the wake of the bankruptcy, critics pilloried A123 as a poster child for what they deemed the folly of the United States subsidizing a domestic clean-energy industry. Most of A123’s battery business was sold in 2013 to Wanxiang Group, an auto-parts company from China, a country that by then had initiated a national push to build up a globally dominant battery sector.

Chastened by the A123 implosion, Vieau figured he’d had enough of the battery business. Then he changed his mind. Today, he is again steering a battery startup that’s fighting a crowded field. This time, though, he isn’t trying to perfect lithium-ion technology. He’s trying to beat it.

Vieau is a director and former CEO of Vionx Energy, a startup based in the Boston suburb of Woburn, Mass. Investors, primarily venture capital firms, have so far poured about $130 million into Vionx and a predecessor company. Vionx—“stupid name, but they always are,” Vieau tells me of the moniker, which is pronounced “Vy-on-ix”—seeks to scale up a wholly different kind of battery, one that can profitably store vast quantities of renewable energy for many hours. Vionx is one of a gathering stampede of companies developing grid-storage technologies that look less like batteries and more, in both function and size, like power plants.

Rather than tweaking space-age materials at nanoscale, as lithium-ion contenders are doing, grid-storage hopefuls work with slabs of metal, industrial pumps and pipes, and chemical brews dumped thousands of gallons at a time into massive tanks.

Vionx’s specific contraption is called a “flow battery.” If it works at scale, it could provide up to about 10 hours of economic storage—perhaps more, with bigger tanks. Over the years, flow batteries have become something of a joke in the energy world. Myriad efforts to scale them up have flopped, both because the technology has been glitchy and because the fossil-fueled grid hasn’t needed much storage.

Vieau’s bet today is that two fundamental changes—better technology and plummeting renewable-energy prices—mean past isn’t prologue. Solar prices have fallen 70% over the past decade. That, plus newly cheap wind power, is boosting demand for energy storage. At the same time, according to Wood Mackenzie, the price of grid-scale-storage systems—the batteries and the rest of the kit necessary to set them up—has fallen 85% since 2010. (See sidebar at left.)

Serious power players are now investing in grid-storage technologies. One is Exelon, which had 2018 revenue of $35.9 billion, is No. 93 on this year’s Fortune 500, and has about 10 million customers. It is experimenting with big batteries and is writing checks to Volta, the battery-tech investment firm. Chris Gould, Exelon’s senior vice president for corporate strategy, says the company has concluded the shift to solar and storage will intensify and that Exelon can profit from it.

Reality check: So far, storage provides only a tiny amount of power to the grid. In 2018, according to Wood Mac­kenzie, there was enough for about 6,000 megawatt-hours of electricity. That’s for the whole world, and it’s less than half the amount of electricity the Falkland Islands use in a year. Even if the grid-storage market achieves the eightfold increase in economic value between 2017 and 2024 that Wood Mackenzie expects, it still will be just one-tenth the value of the electric-car-battery market at that point.

Where it exists, grid storage typically is a creature of government subsidies and mandates. And even given that support, it tends to be concentrated in places, such as California and Hawaii, where renewable energy enjoys maximal economic advantage: places with particularly strong sun and wind and with particularly high fossil-fueled-power prices.

What little energy storage is on the grid today generally amounts to big racks of lithium-ion batteries. That’s a problem for the world—and, Vieau hopes, an opportunity for Vionx. The lithium-ion battery has cornered the market for movable things—toys, watches, phones, electric cars—because it packs a lot of energy into a small package. But today’s grid-scale lithium-ion installations typically can store only a few hours’ worth of juice before they need a recharge. That’s sufficient to stabilize a grid, in the event of an unexpected drop in solar or wind power, until more fossil-fueled electricity can be cranked up and wired out. But it’s nowhere near enough to flip the global power system from fossil fuels to renewables.

LIQUID ASSETS: A device used to test Vionx’s flow batteries, which rely on tanks of chemicals to help store energy.Photograph by Jesse Burke for Fortune
Photograph by Jesse Burke

Vionx contends its technology offers one possible answer. At three government-funded test sites in Massachusetts, Vionx has deployed prototype collections of shipping containers that house its flow batteries. They’re mazes of pumps and pipes, of plastic and metal, that Vieau himself describes as “Rube Goldberg.”

In Shirley, Mass., a Vionx battery is waiting to be hooked up to a field of Chinese-made solar panels. When it’s up and running, it should be able to store enough energy to power about 160 homes. I visit the site on a late afternoon so cold my fingers, as I scribble notes, feel numb. To my eyes, accustomed by now to lithium-ion batteries that would fit in my backpack if not in my pocket, the system looks gargantuan. Not to Vieau. Vionx’s systems, he says, need to be the size of power plants to be viable. “Otherwise, it’s a joke.”

Vionx designs and assembles these systems at its headquarters in Woburn, which looks more like a commercial garage than a lab. Scattered around it are tubs big enough to take a dunk in, though, given that they’re filled with battery acid, that would be unwise.

Shazad Butt, Vionx’s vice president of engineering, gives me a tour. He’s a car guy, having worked for years at Ford Motor before ­moving to A123 and later to Vionx. The lithium-ion battery is “the Ferrari of storage,” he tells me in his flat Michigan accent. “This being the truck.”

Vionx is based on technology developed by and licensed from United Technologies. It uses vanadium, a metal, as the energy carrier in its chemical soup. But the startup faces two fundamental challenges. One is supply. Vanadium is a global commodity with a fluctuating price. Right now, prices are high, undermining Vionx’s economics. The other problem is demand. Government policies, which shape the grid-storage market, were written to support lithium-ion systems, which typically can provide about four hours of backup and which degrade and need to be replaced every few years. But Vionx’s system is sized to be economically competitive for about 10 hours of storage—and to last 20 years or more with essentially no degradation. The system’s beefiness brings higher initial capital costs that pencil out only when amortized over more hours of electricity sales. Buying a Vionx system to produce four hours of juice would be like buying a blowtorch to light a cigar.

“It’s a big issue,” says Vieau, reflecting over a dinner of oysters and fish at one of his favorite white-­tablecloth restaurants in Boston. It’s also a familiar one. He finds himself at Vionx today in much the same dilemma that he did at A123: with an energy-storage device that he’s convinced is technologically ready but that the market doesn’t want, at least not yet. “The question is, ‘Can you get to a point where renewable energy plus storage is cheaper than coal?’ And the answer is yes,” he says, sipping a French Chardonnay. “I’m as convinced today that this is a reality as I was in 2004 that the electric car was going to happen. But the question is, when is it going to happen?”

Vionx is but one of many grid-storage hopefuls wrestling with that dilemma. Another is Form Energy, a startup that grew in part out of the laboratory of Yet-Ming Chiang, an MIT materials-science professor who worked with Vieau as the technological mind behind A123. Form has raised about $11 million, plus a recent $3.9 million grant from the U.S. Department of Energy. Among its other investors are Breakthrough Energy Ventures, a $1 billion clean-energy-technology fund established by Bill Gates and a who’s who of other global billionaires, and Saudi Aramco, the oil giant.

Form aspires to affordably produce radically long-term energy storage—enough not just for 10 hours but for several days or even weeks, which its executives argue will be necessary to reach percentages of renewable energy on the grid that really will phase out fossil fuels. The federal grant Form won was to build a system using sulfur as a key ingredient. Chiang, chatting in his sunny office in Cambridge, Mass., won’t say whether the storage device Form hopes to commercialize will use sulfur. But, choosing his words carefully, he says that “sulfur appears to be one of the most attractive, earth-abundant molecules.” Nonscientific translation of “earth-abundant”: cheap.

A few blocks from Chiang’s office, I visit Malta, a startup spun out last year from X, the skunkworks of Alphabet, Google’s parent. Like Form, Malta, based on Stanford technology, plans to use giant tanks and pumps to store energy for several days or more. But its technology aspires to store energy as heat, an arrangement it sees as more economic. Malta’s investors include Breakthrough Energy Ventures, a Swedish heat-exchange-equipment maker, and a Chinese renewable-energy producer. As if out of a startup documentary, the company is based in a shared workspace in Cambridge where cold-brew coffee and kombucha flow freely and the conference rooms are named for grand projects of civil engineering throughout history. Ramya Swaminathan, Malta’s chief executive, tells me she hopes to have a product on the market in about five years. What most worries her is that Malta is designing a complex piece of machinery for a market that doesn’t yet exist. “It’s the blind man and the elephant,” she notes. “We’re all feeling our way through.”

There’s a palpable difference between the grid-storage startups and the lithium-ion-battery companies I visit. The firms eyeing the electric-car market seem even more harried—because the market wants a better lithium-ion battery right now.

Back in Woburn, a handful of other battery startups sit not far from Vionx. One is Ionic Materials, the brainchild of Michael Zimmerman, a laconic materials scientist who, on the morning I visit, is wrapped in an L.L. Bean fleece jacket. He has spent his career—including several years at Bell Labs, the famed corporate-research outfit—burrowing away on plastics.

Zimmerman began tinkering with how to make better polymers for batteries nearly a decade ago. He has come up with a polymer that, at room temperature, allows ions to flow freely. That raises the possibility of affordably producing a battery that doesn’t need a liquid electrolyte—a “solid-state” battery, which could be safer and, Zimmerman says, even more energy-dense.

Ionic Materials counts among its investors a potent list of multinationals, including the Renault-­Nissan-Mitsubishi alliance; Total, the French oil company; and Hyundai, the Korean automaker. Other investors include Hitachi, the Japanese conglomerate whose products include batteries; and Volta, the energy-storage fund.

Zimmerman’s team of about 50 people is struggling to make the polymer thinner, stronger, more uniform, and cheaper—all in preparation, he hopes, for launching production over the next few years. “This is really hard,” he says, sitting under a wall clock whose face reads, “In Science We Trust,” and tapping the table with his empty coffee cup. “It’s a headbanging process.”

WIRED FOR THE FUTURE: Vionx technician Cuong Tran builds a control unit for a flow battery stack.Photograph by Jesse Burke for Fortune
Photograph by Jesse Burke

Less than a mile from Ionic Materials sits Solid Energy Systems, which is taking an arguably more daring approach. Qichao Hu, the company’s founder, scoffs at the notion of a solid-state battery, saying it may be safer but won’t pack enough energy. He considers a silicon anode similarly ho-hum. Hu, just 33, grew up in Wuhan, China, and got his bachelor’s degree from MIT and his Ph.D. from Harvard. He’s committed to commercializing what among battery researchers has long been seen as a Holy Grail: an anode that will dwarf even silicon in its lithium content because the anode itself is made of lithium metal.

The problem, for years, has been safety. Lithium-metal batteries have a particular propensity, during charging, for the buildup of substances on the anode that can pierce the separator, which can create a short circuit and cause a fire. Hu isn’t worried. He’s confident his battery, which he calls “beyond lithium-ion” and hopes to begin selling for drones next year, will be no more dangerous than those now on the market. “You have cars catching on fire, and still people buy them,” he tells me. “So it’s acceptable.”

Hu talks and works fast. He’s intent on taking his company public as soon as possible, because time is money. “Once the first beyond-lithium company goes public, it’s going to suck up all the investment,” he tells me. “Every one of us wants to be the first.”

Hu has arrived at our 7:30 a.m. meeting in Woburn a few minutes late, a massive travel mug of tea in hand. Both are understandable, given that he has just driven 3.5 hours to the office from his home in New Jersey, a commute he makes weekly.

He’s wearing rumpled blue chinos and dusty work boots—and he’s wearing an identical outfit a week later, when I meet Hu in Shanghai to tour the factory that Solid Energy is building there, in Jiading, a district that also houses major auto factories. Trailing Hu as he walks through the site, the air heavy with the fumes of still-fresh paint, are representatives of several of the investors who in total have poured about $90 million into Solid Energy. They include SAIC Motor, China’s largest automaker, which is based in Shanghai; and Tianqi Lithium, a Chinese company that’s one of the world’s largest producers of lithium, a material that is mined. Among Solid Energy’s other investors: GM and SK.

That many big companies pop up repeatedly across the battery-startup landscape indicates how urgent the technological quest has become. Back on SK’s Korea campus, in the R&D buildings that Hwang, the strategist, won’t let me see, they’re focusing, he says, on improving the cathode and on engineering a separator that’s thin but still safe. SK feels the competitive heat, which is why it’s hedging its bets by backing startups such as Solid Energy. “If we develop things all by ourself,” Hwang says, “it has some risk.”

VW, one of the world’s biggest automakers, agrees. That’s why it announced last year it was investing $100 million in yet another Silicon Valley battery startup, called QuantumScape, an investment that augments VW’s contracts with SK and other huge battery makers. As part of its green remaking, VW says 40% of the vehicles it sells will be battery-powered by 2030. “We need to make decisions right now—who and where is the partner—to secure this enormous quantity of batteries,” says Stefan Sommer, VW’s head of procurement. “It’s the only way to ramp up this huge capacity in this short period of time.”

And that points to a messy yet fundamental reality about the battery race. Despite mounting chest-thumping in national capitals that individual countries must dominate it to safeguard their national security, in practice the battery sector is an increasingly global web. More and more battery firms embody an international mix of intellectual property, investors, and suppliers, to say nothing of customers. Whether these firms are American, or Chinese, or something else is less and less clear. In so many ways, the battery race appears unlikely to stay within established lanes. For consumers and the planet, that may be a very good thing. For policymakers, investors, and the corporate giants of the fossil-fuel era, it will make the race increasingly hard to navigate.

A version of this article appears in the June 2019 issue of Fortune with the headline “The Race To Build A Better Battery.”

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