by Steve LeVine
But silicon had a problem. For use in an automobile, you needed an anode to withstand at least 1,000 charge-discharge cycles. As you intercalated lithium into a silicon anode, it expanded tremendously. Graphite more or less maintained its shape while absorbing the lithium, but silicon blew up three or four times in size. As you charged and discharged again and again, the anode kept expanding and contracting, until it finally pulverized and killed the battery.
This was not news. The virtues of silicon had long been discussed, but no one had yet managed to resolve the expansion issue. Researchers would reach two or three dozen charge-and-discharge cycles, and the anode would break up. Everyone knew that. But Kumar wanted to try his hand. The motivation was a competition run by ARPA-E, the Department of Energy’s new funding unit for radical technologies. The grants, for ideas promising profound leaps in energy technology, ranged from $500,000 to $10 million. Considering that Envia’s entire first round of funding was just over $3 million, the sum in play was beguiling. The prestige of an ARPA-E grant could also attract yet more money and industry attention to Envia’s.
Kumar’s best chance seemed to be twinning a silicon anode with NMC 2.0. Khalil Amine had an interesting concept for silicon, so Kumar applied for the ARPA-E competition with the Argonne scientist as a partner. The submission was straightforward. It named the Amine silicon concept plus a few others that, if coupled with the NMC 2.0, could result in a 400-watt-hour-per-kilogram battery, sufficient to enable a three-hundred-mile car. That seemed to Kumar to meet ARPA-E’s requirement for a transformational breakthrough.
It was a bold proposal—the generally accepted physical limit of a lithium-ion battery using a graphite anode was 280 watt-hours per kilogram. No one had ever created a 400-watt-hour-per-kilogram battery. In all, ARPA-E received some 3,700 submissions for $150 million in awards. Thirty-seven were selected. Envia was among them—Kumar won a $4 million grant.
For the subsequent year, Kumar’s team worked through the handful of silicon anode concepts he had proposed until it settled on one. Kumar said Amine’s anode, a composite of silicon and graphene, pure carbon material the thickness of an atom, had failed to meet the necessary metrics. Instead, the best anode was made of silicon monoxide particles embedded into carbon. Kumar’s team built pores into this silicon-carbon combination measuring between 50 nanometers and 5 microns in diameter, and filled them with electrolyte. Carbon in the shape of fibers or nano-size tubes were also mixed into the anode, thus creating an electrically conductive network. The silicon’s expansion was thus redirected and absorbed. Even if the silicon broke apart immediately, the carbon fibers and tubes provided a path across which the lithium ions could pass on their way to and from the cathode.
Kumar said the results were excellent but that there was a disadvantage to working at nanoscale. This path to the better battery was expensive. You started with a vacuum reactor and a costly substrate, sometimes using platinum, a precious metal. Then you grew nanowires and nanotubes. What resulted was like pixie dust—you derived just milligrams of material each time while what was required was bulk powder. The process might decline in cost over time, but for now it could not be justified.
Perhaps there was a cheaper way. What if his team skipped the vacuum reactor and the platinum and instead employed a conventional furnace to transform a precursor of cheap silica into good-quality, ten-gram lots of powder, just enough to make coin cell samples? That would significantly reduce the cost. Kumar’s team would try.
The jerry-rigging worked. Together, the cheaper components—including Kumar’s version of NMC 2.0 on the cathode side—were delivering the milestone energy density of 400 watt-hours per kilogram.
When he heard of the success, Arun Majumdar, the director of ARPA-E, already a fan of Envia’s, was elated. He said that Kumar should now seek independent verification. This was a very big deal and Kumar would want to validate his claim through an unimpeachable expert or body.
Kumar sent the material to Crane, a respected Indiana-based evaluation division of the Naval Surface Warfare Center. Crane came back with a stamp of approval—it had put the cell through twenty-two charge-discharge cycles and confirmed the 400-watt-hour-per-kilogram energy density. Kumar had reached the milestone.
It was a considerable achievement, perhaps big enough, Majumdar said, to justify its announcement at the annual ARPA-E Summit in Washington, which was just two months away. Former president Bill Clinton and Microsoft cofounder Bill Gates would both be keynote speakers. Majumdar said he would let Kumar know his decision.
The prospect of such attention animated Kumar and his partners. The spotlight would be of incalculable promotional value considering their aspirations for an IPO. Awaiting Majumdar’s decision, Kumar traveled for a dress rehearsal at the Orlando conference.
• • •
Kumar walked on stage at ChampionsGate wearing a dark blue suit. Flipping through a slide deck, he said that what he was describing did not involve a typical laboratory experiment—it was not grams of material encased in a nickel-size coin cell, but a standard 45-amp-hour electric-car battery, vacuum-sealed inside a manila-envelope-size pouch. It was a breakthrough that could finally enable the long-range, affordable electric car.
Kumar recounted some facts about NMC 2.0—if you pushed the charging voltage to 4.5 volts, the blockbuster cathode, twinned with a graphite anode, delivered 280 watt-hours per kilogram, double the performance of the lithium-cobalt-oxide material contained in the audience’s smart phones and laptops. But you achieved a wallop when you swapped in the silicon-carbon anode—400 watt-hours per kilogram, which was “a world record,” Kumar said. In addition, the advance reduced the cost to just $250 per kilowatt-hour, half that of lithium-cobalt-oxide. Just two years in the future, he said, the cost would be down to $180 a kilowatt-hour.
The battery was only a prototype—he had charged and discharged it just three hundred times. Experts in the audience knew that Kumar would have to more than triple the number of cycles before the battery could be used in a car. Kumar himself would tell you that climb would be “very tough. Very complicated.” Another $4 million or $5 million in R&D spending might be required to reach all the way there. Challenges remained. But Envia was “breaking the barrier,” he said.
One by one after the presentation, the representatives of GM, Dow Chemical, and Hyundai approached Kumar. They wanted a private word.
Anderman, the conference organizer, said Kumar was exaggerating. His talk had served a purpose, he said—it had demonstrated to the shell-shocked industry that companies were still trying. He had invited Kumar to speak for precisely that reason. “But there is no breakthrough at Envia,” he said. Like everyone in the industry, Kumar was working to stop silicon from swelling, but he had not done so as yet. Neither had he achieved 400 watt-hours per kilogram. He was hyping his achievements.
Jeff Dahn, the Canadian researcher at Dalhousie University in Halifax, felt differently. One of the most original minds in batteries, Dahn was notorious for ripping into the ideas of his colleagues—publicly and usually with precision. He pointed out flaws that most battery guys, knowing how hard it was to make an advance of any type, typically kept to themselves. Dahn was with Anderman in the belief that battery scientists often cherry-picked their results in order to postulate nonexistent advances. That did not make him a pessimist—he was a true believer, confident that scientists would eventually get it right. To reach that point, they needed first to stop doctoring the results and be honest with the world and themselves. Dahn had recently delivered blunt PowerPoint presentations that, spliced with videos of exploding batteries, accused fellow scientists, including Khalil Amine, of camouflaging the risk that their inventions could catch fire. But Kumar, he said, was not a member of this group of embellishers.
Dahn was unusually complimentary to Kumar. What the Envia man unveiled was not necessarily elegant—it was really an engineering feat, packed together efficient
ly. But it also worked. “It looks like it can get to four hundred,” he said. “I am very familiar with the materials that he is talking about and I think it is doable.”
Dahn was acting coy. Back in 1999, the 3M Company had filed a patent application for his version of NMC just a few months after Argonne. In the subsequent years, Thackeray and Dahn bickered over the precise atomic structure of NMC—was it a saucy amalgam of nickel, cobalt, manganese, and lithium (Dahn’s position), known as “solid solution,” or a more structured composite with a discernible chemical architecture (Thackeray’s)? For the motorist, the difference seemed to be immaterial. But it could prove crucial should NMC 2.0 become part of a massively best-selling battery. Thackeray had managed to win the crucial original American patent while the 3M Company had grabbed patent rights in China, Japan, and South Korea. 3M had gone to war with pilferers of NMC—Sony, Matsushita, and Panasonic—and won. The details of the settlements were sealed, but the outcome upheld the Dahn patents. 3M had filed no suit against Argonne, but Dahn made it sound like one was possible. He said, “I think Argonne and 3M are not on the best terms.” It was only a matter of time before 3M went after GM, too. In Dahn’s view, it was his IP and not Argonne’s that was contained in the Volt. “I think that Argonne is just using this composite argument to stay outside the 3M patent,” he said.
When Dahn was younger, he could get worked up over who was tromping on his perceived turf, but he said he welcomed Kumar’s work on NMC. There was an enormous gulf between achieving three hundred and one thousand charge-discharge cycles. “That is going to take some time,” Dahn said. But for starters, three hundred cycles “look pretty darn good” if one was aiming at smart phones and laptops. Such performance would give longer life at the same cost as current batteries. “I am sure Apple would love to make the iPhone lighter and thinner,” he said.
Was his position on Envia a more positive, new Jeff Dahn?
“No. I am being realistic,” he said.
Do the math, Dahn said. The basic NMC-spinel battery in the GM Volt delivered about 100 watt-hours per kilogram. Since GM overengineered the battery to maintain a margin for error, about 37 percent of it went unused—the excess was there just in case added capacity was needed. So it was effectively running at about 66 watt-hours per kilogram. If you now doubled the capacity using the Envia formulation and slimmed down the unused capacity, you would triple your range—rather than 40 miles, the Volt would travel more than 120 miles on a single charge.
Alternatively, GM could stay with the 40-mile range and cut about $10,000 off the price of the car. “You have your choice,” Dahn said. “This is why people are fighting for higher energy and longer life. It is what it is all about.”
Dahn had questions. For example, why didn’t Kumar report more data? What happened after three hundred cycles? But he was not worried—they were familiar questions. The first lithium-ion battery—Sony’s 1991 technology—was “a piece of junk.” But since then, its performance had improved by a factor of two, making lithium-ion tower over anything that existed previously. Envia’s three hundred cycles would increase. “How long and how fast? Nobody knows,” Dahn said. “But you can bet your bottom dollar it is going to get better.”
33
ARPA-E
Two weeks after Orlando, Arun Majumdar presided over the ARPA-E Summit. He staged an atypical show for the unexciting Department of Energy. It opened with an appeal from Bill Clinton to Congress to significantly increase ARPA-E funding. The agency had much left to do and monumental gains to achieve, Clinton said. His image flashing onto three large screens within a large, darkened room, Clinton argued for ambition. Do not become mired in fretting. If you entered the room pessimistic, leave thinking of the grand possibilities, he said.
Clinton vanished behind a curtain and was replaced by Bill Gates and Steven Chu. They settled into armchairs. Gates was known for Windows, education, and health philanthropy, and not for his chops in energy. But Canadian energy thinker Vaclav Smil was his favorite writer, and Gates was a seed investor in a molten metal battery prototype invented by Donald Sadoway, a celebrity MIT chemist. Conversing with Chu, Gates said that clean power was perhaps the world’s greatest challenge. It would be exceptionally harder than anything he himself had attempted. Gates said that when you contrasted energy and computer software, “people underestimate the difficulty getting the breakthroughs. And they underestimate how long it is going to take.” Crossing from the invention to the marketplace was the longest wait of all—the general adoption of a new energy technology could take five to six decades, he said.
That’s right, Chu replied. You could achieve an extraordinary advance, but no one could know when or whether it would be embraced by consumers. If you did not believe him, he said, go downstairs to the rows of new battery prototypes on display in the ARPA-E exhibition room. Single out the one that will capture the market and “go and invest in that.” Such intuition stood little chance in deciphering the right electrochemical pathway.
Chu continued: “We need literally thousands of companies trying to increase the odds that we will end up with the ten or twenty approaches that will give us the magic solution.” But the rewards for success would be astronomical. If someone for instance managed to combine breakthroughs in inexpensive batteries and solar cells, he said, the resulting invention would “go viral in the same way that cell phones went viral.” It would do good in the world, since village populations in frontier countries could finally have power and electric light, and would create numerous vast fortunes. “Let’s not blow it” through miserly energy research budgets, Chu said. “There is a huge market out there.”
Majumdar took the podium. He claimed the keynote spot for himself.
Another alumnus of India’s Institutes of Technology, Majumdar had previously been deputy director of the Lawrence Berkeley National Laboratory under Chu. In 2009, when Chamberlain held the very first pre-Hub meeting, Majumdar led the Berkeley delegation alongside electrochemistry pioneer John Newman. Although not a Bell veteran, a Nobel laureate, or a scientific impresario, Majumdar brought something more to the stage. Chu projected charm and charisma but Majumdar, resonant, grave, and confident, was theatrically masterful. In the basement, he said, were exhibitions of 180 select inventors—“the Wright brothers, Borlaugs, Salks, and Teslas of the twenty-first century. They are the crown jewels of our nation.” They would help create the future. Nine merited special attention. He began to tick them off, flashing slides to punctuate their achievements.
About midway through, Majumdar said that a battery powerful enough to propel a car the 225-mile distance from Washington, D.C., to Manhattan would cost $30,000. “Just the battery pack,” he said. Since very few people could afford a car containing such a battery, ARPA-E had challenged the research community three years earlier to create a battery that could compete with gasoline in range and cost. Then, he said, “Let me tell you the story now of Envia.”
A photograph of Kumar and the Envia team went up on the triple screens. The day before, Majumdar said, this start-up company had announced “the world record in energy density of a rechargeable lithium-ion battery.” Its 400-watt-hour-per-kilogram battery, if scaled up, could take a car that entire Washington-to-New York journey in a single charge at half the cost of the current technology. And more was coming, he said.
The New York Times, granted an exclusive the previous evening, seemed uncertain how to treat the news. Its cautious headline read, “ENVIA CLAIMS ‘BREAKTHROUGH’ IN LITHIUM-ION BATTERY COST AND ENERGY DENSITY.” Restraint vanished in the hours following Majumdar’s presentation. One reporter declared Envia “the Golden Child” of the summit. Everyone was discussing the company, the story said. Scientific American recalled Envia’s humble beginnings in the Palo Alto Library and calculated that its battery could fuel a three-hundred-mile car trip from St. Louis to Chicago for $10, an eighth of the cost of a gasoline fill-up for the same journey.
They knew their remonstrations rang of sour grapes. For Argonne, not to mention others in the industry, the situation was confounding. How was Envia, a lab with three dozen researchers operating on a comparatively shoestring budget, managing advances that surpassed everyone else’s, including the inventors of NMC 2.0? How had the company eclipsed the other NMC licensees, not to mention the Asian giants, all of whom were also working on both voltage fade and the silicon anode? Kapadia partly credited good office politics: All subjects were fair game—as long as they were respectful, any scientist could and often did debate any other. Anyone could attempt any experiment that he wished. Money was not held tight—they had $650,000 a month to spend and as long as the staff did not exceed it, no one challenged expenses. Kapadia said he worked “seamlessly” with Kumar, who was “a genius.”