What If Electric Cars Were Better?

Improving the energy density of batteries is the key to mass-market electric vehicles.

• BY DAVID ROTMAN

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Electric vehicles are still too expensive and have too many limitations to compete with regular cars, except in a few niche markets. Will that ever change? The answer has everything to do with battery technology. Batteries carrying more charge for a lower price could extend the range of electric cars from today's 70 miles to hundreds of miles, effectively challenging the internal-combustion motor. 

To get there, many experts agree, a major shift in battery technology may be needed. Electric vehicles such as the all-electric Nissan Leaf and the Chevrolet Volt, a plug-in hybrid from GM, rely on larger versions of the lithium-ion batteries that power smart phones, iPads, and ultrathin laptops. Such gadgets are possible only because lithium-ion batteries have twice the energy density of the nickel–metal hydride batteries used in the brick-size mobile phones and other bulky consumer electronics of the 1980s. 

Using lithium-ion batteries, companies like Nissan, which has sold 20,000 Leafs globally (the car is priced at $33,000 in the U.S.), are predicting that they've already hit upon the right mix of vehicle range and sticker price to satisfy many commuters who drive limited distances.

The problem, however, is that despite several decades of optimization, lithium-ion batteries are still expensive and limited in performance, and they will probably not get much better. Assembled battery packs for a vehicle like the Volt cost roughly $10,000 and deliver about 40 miles before an internal-combustion engine kicks in to extend the charge. The battery for the Leaf costs about $15,000 (according to estimates from the Department of Energy) and delivers about 70 miles of driving, depending on various conditions. According to an analysis by the National Academy of Sciences, plug-in hybrid electric vehicles with a 40-mile electric range are "unlikely" to be cost competitive with conventional cars before 2040, assuming gasoline prices of $4 per gallon.

Estimates of the cost of assembled lithium-ion battery packs vary widely (see "Will Electric Vehicles Finally Succeed?"). The NAS report put the cost at about $625 to $850 per kilowatt-hour of energy; a Volt-like car requires a battery capacity of 16 kilowatts. But the bottom line is that batteries need to get far cheaper and provide far greater range if electric vehicles are ever to become truly popular. 

Whether that's possible with conventional lithium-ion technology is a matter of debate. Though some involved in battery manufacturing say the technology still has room for improvement, the NAS report, for one, notes that although lithium-ion batteries have been getting far cheaper over the last decade, those reductions seem to be leveling off. It concludes that even under optimistic assumptions, lithium-ion batteries are likely to cost around $360 per kilowatt-hour in 2030.

The U.S. Department of Energy, however, has far more ambitious goals for electric-vehicle batteries, aiming to bring the cost down to $125 per kilowatt-hour by 2020. For that, radical new technologies will probably be necessary. As part of its effort to encourage battery innovation, the DOE's ARPA-E program has funded 10 projects, most of them involving startup companies, to find "game-changing technologies" that will deliver an electric car with a range of 300 to 500 miles.

The department has put $57 million toward efforts to develop a number of very different technologies, including metal-air, lithium-sulfur, and solid-state batteries. Among the funding recipients is Pellion Technologies, a Cambridge, Massachusetts-based startup working on magnesium-ion batteries that could provide twice the energy density of lithium-ion ones; another ARPA-E-funded startup, Sion Power in Tucson, Arizona, promises a lithium-sulfur battery that has an energy density three times that of conventional lithium-ion batteries and could power electric vehicles for more than 300 miles.

The ARPA-E program is meant to support high-risk projects, so it's hard to know whether any of the new battery technologies will succeed. But if the DOE meets its ambitious goals, it will truly change the economics of electric cars. Improving the energy density of batteries has already changed how we communicate. Someday it could change how we commute.

The Year in Materials

Vibrant displays head to market, invisibility cloaks become more practical, and batteries store more energy.

• BY KEVIN BULLIS

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Tiny crystals called quantum dots emit intense, sharply defined colours. Now researchers have made LED displays that use quantum dots. QD Vision demonstrated its first rudimentary one-colour displays using nanoscale crystals five years ago. This year it demonstrated a full-colour display capable of showing video. The company says it could be another five years before the technology appears in commercial displays. Samsung might get there first—it's also developing quantum-dot displays and demonstrated a full-colour one in February.

Quantum-dot displays could use far less energy than LCDs. Another ingenious way to reduce energy use is to make displays that emit no light but instead reflect ambient light, an approach Qualcomm is taking with its full-colour Mirasol displays, which use only a tenth of the energy of an LCD. The technology has started to appear in tablet computers in South Korea.

No display looks good after it's covered with fingerprints. A new coating based on soot from a candle flame could provide a cheap oil-repelling layer that could eliminate smudges.

Novel nanostructured materials could significantly enhance the power output of solar panels and make them cheaper by capturing light that would have otherwise been reflected. They could also achieve these goals by converting near-infrared light into colours that conventional silicon solar cells can absorb. Another material could render stealth aircraft invisible at night—and invisible to radar night and day.

Metamaterials offer another approach to invisibility: instead of absorbing light, metamaterials bend it around an object. Until this year, researchers have only been able to make metamaterials on a small scale—less than a millimetre across. Now they've made them big enough to be practical. They don't work yet for all wavelengths of light, but they could render objects invisible to night vision equipment.

Stanford researchers built a battery electrode that can be recharged 40,000 times—compared to the 1,000 charges you'd get with a typical laptop battery. Since the electrode lasts so long and is made of abundant materials, it could provide an inexpensive way to store power from wind turbines and solar panels.

Other researchers have developed inexpensive materials that can store 10 times as much energy as conventional graphite electrodes in lithium-ion batteries. Paired with an equally high-capacity opposite electrode, these could transform portable electronics and electric vehicles. One technology from Lawrence Berkeley National Laboratory seems promising because it uses a conductive polymer that can be incorporated into existing manufacturing lines instead of requiring the expensive new technology for making nanostructures required by others.

New tools could speed up the next materials breakthroughs. A modelling program developed at Harvard has led to one of the best organic semiconductors ever made. And a robotic system for making thousands of battery cells with unique electrode chemistries has discovered materials that could boost lithium-ion battery storage capacity by 25 per cent.

The Year in Numbers

A look back at 2011's biggest technology stories, by the numbers.

• BY MIKE ORCUTT

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Japan's nuclear catastrophe

The disaster at Tokyo Electric Power's Fukushima Daiichi nuclear power plant, set off by a 9.0 magnitude earthquake off Japan's east coast, scored a 7 out of 7 on the International Atomic Energy Agency's International Nuclear and Radiological Events Scale. The metric ranks severity based on many parameters, including an incident's effects on humans and the environment. According to the Japanese government, decommissioning the plant will take 30 to 40 years, and cost an estimated $15 billion.

Many nations reacted by scaling back their nuclear ambitions. Germany led the way, announcing that by 2022, all 17 of its nuclear reactors will be shut down. Those reactors, according to the World Nuclear Association, generated 133 billion kilowatt-hours in 2010, or28.4 percent of the country's electricity.

As of December 2011, there are still 433 operating nuclear power plants in the world. The United States has the most, with 104. Meanwhile, 499 more reactors are either planned or proposed globally—171 of those are in China, which currently has 26 operable reactors.

(See A Worldwide Nuclear Slowdown Continues and What Will A Nuclear-Free Germany Cost?, by Peter Fairley, and Small Nukes Get Boost, by Kevin Bullis.)

The solar industry in transition

The average nominal (not adjusted for inflation) price of crystalline silicon solar panels fell from $1.90/watt to $1.35/watt from January to November 2011, according to GTM Research. The solar industry is facing a large oversupply of panels, fueled largely by manufacturers in China, home to four of the top five largest solar-panel manufacturers in the world.

The world's solar capacity continues to grow quickly. GTM Research estimates that more than 20,563 megawatts of solar power were installed globally in 2011 (13,553 megawatts in Europe, 2,083 in North America, 3,938 in Asia,710 in Australia, and 279 megawatts in the rest of the world). That is 2,960 more than were installed last year, and brings the total global solar capacity to 59,152 megawatts.

(See The Chinese Solar Machine, by Kevin Bullis, and Can We Build Tomorrow's Breakthroughs? by David Rotman.)

Data deluge

The amount of data we create, replicate, and store in gadgets and the cloud is growing at a staggering rate. According to IDC, the total "digital universe," or all the digital information that has been created or replicated, grew to 1.8 zettabytes in 2011 (a zettabyte is a trillion gigabytes) in 500 quadrillion files. IDC says the total size has grown by a factor of nine over the past five years. Handily enough, in August, researchers at IBM unveiled the largest harddrive ever, capable of holding 120 petabytes (a petabyte is a million gigabytes), or about 24 billion five-megabyte mp3 songs.

(See IBM Builds Biggest Data Drive Ever, by Tom Simonite, and The Cloud Imperative, by Simson Garfinkel.)

Google tries social (again)

Google took a second shot at social networking with the release of Google+, which is a lot more like Facebook than its failed first attempt, Buzz, which was more comparable to Twitter.

Sign-ups skyrocketed in the days immediately after the introduction of the new service on June 28, hitting the 10 million mark about two weeks later. By October, the last time Google released user numbers, total sign-ups stood at 40 million. Active use of Google+ has been harder to gauge, but whatever the number, it's still dwarfed by Facebook's claim of 800 millionactive users.

(See Tom Simonite's Q&A with Bradley Horowitz, the man building Google+, and How Google+ Will Balkanize Your Social Life, by Paul Boutin.)

Automakers electrify

General Motors and Nissan released their anticipated, and much-hyped, electric models at the very end of 2010. As of December 1, GM had sold 6,468 Volts, well short of its goal of 10,000. Nissan, meanwhile, claims it has reached its 2010 global sales goal of 20,000 Leafs.

(See Will Electric Vehicles Finally Succeed?, by Peter Fairley, and A Wish List for the Next GM Volt, by Kevin Bullis.)

Stem-cell trial halted

In November, biotechnology firm Geron halted its stem-cell research program, including the first U.S.-approved clinical trial of human embryonic stem cells. The company, which spent $45 million just to gain approval from the U.S. Food and Drug Administration for the landmark trial, only treated four patients.

(See Stem-Cell Gamble and Geron Shuts Down Pioneering Stem-Cell Program, both by Antonio Regalado.)