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Energy

Battery Booster

A new DOE program is a financial lifeline for energy-storage start-ups

by Melody Voith
December 6, 2010 | A version of this story appeared in Volume 88, Issue 49

POWER START
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Credit: Planar Energy
A Planar Energy technician prepares the process for chemical deposition of battery materials.
Credit: Planar Energy
A Planar Energy technician prepares the process for chemical deposition of battery materials.

Cutting-edge consumers eagerly awaiting their chance to purchase a Chevy Volt or a Nissan Leaf will put their trust in lithium-ion batteries that have been scaled up to electric-vehicle proportions. By the time second-generation plug-in hybrid and all-electric vehicles reach the masses, they will contain much more powerful batteries sporting a new technology. But what that technology will be is still not known.

The future of electric-car batteries is a wide-open research and development space and a huge opportunity for U.S. science and manufacturing, experts say. For the U.S. to emerge in front of its global competitors, however, one or more of a host of possible advanced technologies must prove its mettle.

In May, 10 teams from battery technology start-ups and university and government laboratories were awarded grant money through the Department of Energy’s Advanced Research Projects Agency-Energy. The ARPA-E money will support development projects for two to three years, at which point the teams that have met two sets of ambitious milestones should be ready to demonstrate working prototypes.

The ARPA-E program, known as Batteries for Electrical Energy Storage in Transportation, was not designed to reward mere incremental improvements in battery power. As the acronym BEEST implies, funds went to programs that promise to at least double the performance of the best of today’s lithium-ion batteries.

The program took its marching orders from specifications developed by automakers that participate in the U.S. Advanced Battery Consortium. “Right now, with some of the batteries we have, you don’t think of a big honking powerful engine like a Hemi, but that’s what we want them to be—like the beast under the hood,” says an ARPA-E official who is not authorized to speak on the record.

The official adds that the focus of the ARPA-E investment is on the early prototyping stage, where there is enough risk that the private sector won’t take a gamble.

The U.S. government has also heavily incentivized manufacturers to produce lithium-ion electric-car batteries in the U.S. But the U.S. is not likely to catch up to Asian producers in developing and manufacturing standard lithium-ion batteries, says Dallas Kachan, managing partner of the clean technology research firm Kachan & Co.

The U.S. stands a better chance with newer technologies, according to Kachan. “Air and flow-based chemistries are the ones to watch, in our analysis.” Still, he cautions, “the ARPA-E recipients aren't necessarily ahead of start-ups, researchers, and large corporations elsewhere. There's lots of innovation going on globally.”

All the grant awardees represent high-risk technologies, but some are riskier than others. On the low end are projects that marry new manufacturing methods to next-generation, high-density lithium-ion-battery concepts. From there, risk increases for technologies such as lithium-sulfur, magnesium-ion, lithium-air, and zinc-air, followed by ultracapacitors and an “all-electron” battery.

C&EN spoke with executives at four battery start-ups about their winning technologies and how the ARPA-E grants—between $3 million and $5 million apiece—will help accelerate their development activities.

Orlando, Fla.-based Planar Energy claims its solid-state lithium-ion battery design can deliver three times the energy density of today’s lithium-ion batteries at less than half the cost per kilowatt-hour. The solid-state inorganic nature of the battery is the key to its high performance, says M. Scott Faris, the firm’s chief executive officer.

One problem with current battery performance, Faris says, is the need to package the active material of the cathode with binders, separators, and liquid electrolytes. “You only get a fraction of the theoretical energy density,” he explains. With Planar’s design, he asserts, “you can get around 95% of the theoretical energy density of the active materials.”

The temptation to try solid-state lithium-ion batteries is not new, but earlier trials ran into cost barriers. Early innovators borrowed vacuum deposition technology from the semiconductor industry, then found themselves with a process that cost 20–30 times what it should to be competitive.

The Planar process deposits semiconductor-quality films from a solution. The nanostructured films are grown directly on a substrate and then sequentially on top of each other. Faris says the process allows the firm to “spray-paint a cathode, then a separator/electrolyte, then the anode. It can be cut and stacked in various form factors.”

Planar was spun out of the National Renewable Energy Laboratory in 2007. When combined with traditional venture capital, the ARPA-E funding “allows us to accelerate our work” by developing technology and manufacturing processes in parallel, Faris says. In addition, the funds will go to equipment and to hiring chemists and other scientists.

Like the other start-ups in the ARPA-E program, Planar aims to commercialize smaller batteries before tackling electric-car versions. The firm is in talks with consumer electronics firms, Faris says. A possible early market for the solid-state batteries would be new, power-hungry 5G cell phones.

Energy Delivery
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Credit: ReVolt Technology
During discharge of a ReVolt zinc flow air battery, an auger system pushes a slurry of zinc through a reaction chamber with air electron tubes, where it forms zinc oxide. Because the zinc stays in a liquid form, it does not form dendrites that can damage the battery.
Credit: ReVolt Technology
During discharge of a ReVolt zinc flow air battery, an auger system pushes a slurry of zinc through a reaction chamber with air electron tubes, where it forms zinc oxide. Because the zinc stays in a liquid form, it does not form dendrites that can damage the battery.

Another awardee, ReVolt Technology, aims to go to market with an even smaller battery. ReVolt is working on a zinc-air flow “button cell” battery to power hearing aids. The first model will be a primary, or nonrechargeable, battery, but CEO James P. McDougall says it will be followed by a rechargeable version.

Founded in 2004, ReVolt is a spin-off of Norwegian contract research institute SINTEF. It is now moving its corporate headquarters from Switzerland to Portland, Ore., in large part to take advantage of U.S. incentives for cleantech businesses.

Zinc-air batteries are already used in hearing aids, but they are not rechargeable, and do not store much energy. ReVolt has reconfigured how zinc is stored in the battery to increase the energy density and support hundreds of charge and discharge cycles.

A combination of three technological advances prompted the spin-off from SINTEF, according to McDougall. First was the development of a bifunctional air electrode that oxidizes the zinc and permits recharging. Second was a system to manage humidity, and third were gelling and binding agents to keep zinc dendrites from forming. The formation of dendrites in a battery can pierce the separator, causing the battery to short circuit.

The ARPA-E money will cover most of ReVolt’s overhead for three years. The firm will have about 25 employees by the end of 2011, says McDougall, who hopes the project will grow to about 50 people. “We’ll be ready to shift at that point from beta to early production trials and product-line development if we are successful with our first and second set of milestones.”

The milestones are aggressive goals set by ARPA-E officials. “We have a pretty good chance of achieving most of the primary objectives,” McDougall predicts. “As for the secondary ones, we’ll have to see when we get further into the program. The grant will have a big impact on our business and will help to accelerate our development by probably about two years.”

The milestones that ReVolt and the other teams must meet include high energy densities and low system costs. The secondary milestones do not all need to be met, but gaining the full award requires beating the competition on most of them. They include a doubling of the first set of energy-density requirements, support for many charge and discharge cycles, long life, wide temperature stability, safety, and recharging efficiency.

Energy density gets primary attention because it determines how far a car can go once it is charged. Road warriors might be attracted to an electric vehicle that can travel 300 miles without plugging in. That’s the claim made by Sion Power. Sion is developing a lithium-sulfur battery that, it says, will have three times the energy density of lithium-ion batteries.

John Affinito, Sion’s chief technology officer, says lithium-sulfur batteries promise higher energy densities than competitors such as magnesium-ion and fewer technical limitations than lithium-air batteries.

Sion claims that its method to protect the lithium anode from being depleted by solvents in the electrolyte is what sets it apart from other groups trying to commercialize lithium-sulfur cells. The company is working with its materials supplier BASF to develop what it calls “multifunctional membrane assemblies” to further protect the lithium.

Two hurdles the company will need to overcome, Affinito acknowledges, are charge/discharge cycle life and high-temperature stability. Still, he points out, Sion batteries are already being used in unmanned air and ground vehicles.

Affinito says the BEEST grant will accelerate Sion’s research program by two years. “Our investors are willing to go it alone—they would just go a little slower. In this market, speed is important.”

Protecting lithium is also what will make lithium-air batteries work at PolyPlus, another ARPA-E awardee. PolyPlus has partnered with industrial glass firm Corning to design protective layers that keep the lithium core electrochemically active while staying chemically isolated from the external electrolyte.

The government funding has jump-started hiring and a faster development plan for lithium-air batteries, says PolyPlus Chief Technical Officer Steven Visco, who characterizes lithium-air technology as “very high risk” (C&EN, Nov. 22, page 29).

“The ARPA-E award allowed us to join forces with Corning,” Visco continues. “We had been talking to them, but this was the perfect opportunity to combine the talent of two firms to advance not only rechargeable technology but also other projects under development.”

The timing of the grants should make a big difference to technology start-ups that would otherwise struggle for lack of early cash, Kachan says. “Battery companies might find an awfully small amount of money is all it will take to ‘productize’ their science in a way that shows commercial potential. It doesn’t have to be a product they can sell, but they can demonstrate to private capital investors that they have something important.”

In addition to providing breathing room to create a prototype, the BEEST program is helping to connect technologists to technology-savvy business people, and even to venture capital investors, Planar’s Faris says.

“Quite honestly, this is the most well run and most market-oriented program I’ve ever seen,” Faris says. “It’s the new kid on the block and staffed with venture capitalists. The core people are all venture capitalists or have come from industry, and they are attuned to the sensitivities of companies, including the time cycle companies need to operate in.”

The battery firms all say they will pursue manufacturing in the U.S. once they’ve reached commercialization. “We are embarking on a mission to bring energy-storage supremacy back to the U.S.,” Faris promises. And as Sion’s Affinito points out, “As with most DOE programs, they have a statement that you swear to that you are planning to produce in the U.S., which is our plan.”

For companies pursuing advanced batteries in the U.S., the international competition will be tough, Kachan observes, citing international start-ups such as Oxis Energy, Amperex, CAP-XX, Nanjing Volt Technology, Panyu, Electrovaya, Pure Energy Visions, Able New Energy, and Deeya Energy.

ReVolt’s McDougall says his time abroad showed him that Germany, the U.S., and China have been the most aggressive in supporting, at a government level, a mandate to move industry in this direction. Still, he says, more work needs to be done. “I hope the U.S. can keep its mandate and be aware of what’s happening in Germany, China, and even Singapore.”

Since World War II, the U.S. has proven it can quickly rally to a new challenge, McDougall observes. “Even though the U.S. got started a bit later than other countries on advanced batteries, if we stay focused the country will have a strong position in these markets,” he says.

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