The Driving Experience of Electric

The Sound of Electric - Fisker Karma accelerating

Lithium Ion Chemistry at SBU

From the get-go, it does not look snazzy.  Resembling a hearing aid battery, it doesn’t echo an image of the Flux Capacitor from the movie Back to the Future, nor does it look remotely anything that could power a next generation electric car.  It is one of many coin cells scattered in various stages of assembly in an utilitarian looking lab at Stony Brook University. Hua Xiao, a graduate student researcher from China and member of the Clare Grey chemistry research team, takes the helm for the day.

            “It’s my second time making lithium batteries,” he said, smiling nervously.

            Xiao’s hands dig around in an argon gas-filled glove box.  His movement is unwieldy in the see-thru box that makes his fingers appear twice their size.  It is necessary to assemble such batteries in an environment devoid of oxygen so that its contents do not react and render the battery useless. Argon is an inert gas and does not react. From the vast chemical cookbook of different lithium-ion battery technologies already installed to in laptops and cell phones, Xiao is preparing a test battery for an ongoing experiment in uncovering superior battery chemistry.

            In part of the race to discover the perfect chemical composition for rechargeable batteries, Xiao’s battery, made from lithium metal and copper fluoride, is far from perfect or even ideal. It is unstable and prone to explode. However, through a long and tedious process of trial and error, Xiao’s objective is to find exactly why it doesn’t work and what will work.  The efforts of Xiao and the Clare Grey team shadow a global scientific quest to scale up the batteries that give our everyday electronics juice. One day, they hope that these beefed up batteries will power the next generation of plug-in hybrids and all-electric vehicles.

            Even before President Obama’s national address in late march clamoring for a million hybrid electric vehicles to be on the road by 2015, the demand for electric hybrids and electric-only vehicles has been strong. According to a Duke University study, US sales blossomed from 10,000 in their introduction in 2000 to about 346,000 in 2007.  Sales took off in this decade due to a combination of increasing gasoline prices and government tax-rebates and credits. The most popular hybrid car, the Toyota Prius, was first introduced in Japan in 1997 and accounted for 52% of all US hybrid sales in 2007.

            “Consumers are clamoring for more efficient vehicles,” Luke Tonachel, Vehicles Analyst at the Natural Resources Defense Council said. “Especially in the gas spike of 2008.”

            American car companies are definitely taking notice too. In 2010, General Motors is set to release its first hybrid electric vehicle, the Chevrolet Volt, at a price of $40,000 before government subsidies. The Volt can be charged using conventional household outlets and can be completely powered by its onboard lithium-ion battery for an electric range of 40 miles. A less well-known company, Tesla, is producing an all-electric sports car that is capable of accelerating from 0-60 in 3.9 seconds at a price tag of around $100,000. The Tesla uses lithium ion iron phosphate battery technology.

            A current estimate puts the cost of refueling (or recharging) an electric car at $1 in North Carolina compared to the much higher cost of gasoline. Rates vary around the country depending on how much electricity costs in the area. Before companies like LG develop these batteries specifically for these types of cars, universities like Stony Brook, funded by the US Department of Energy, has to conduct basic research on battery compositions. The research has intensified in the last decade. Some of Grey’s greatest challenges are to overcome chemical limitations to give batteries more capacity and deal with safety issues like overheating and explosions.

Under the economic stimulus bill, Obama has plans to inject $2.4 billion to put Americans to work on hybrid and electric vehicle batteries and pull the United States from a hundred years of oil dependency and foreign insecurity. Clare Grey, a Stony Brook University chemistry professor and her research team of post doctorate and graduate students, has been part of the national search with other universities like MIT and Rice University since 2001.            

 

 

The Stubborn Dog

 

            With a clumsy gloved hand in the argon chamber, Xiao unscrews a jar containing a thick ribbon of silvery lithium. He carefully pulls a piece off and proceed to scrub the metal with a well-worn toothbrush. Lithium, he explains, is not always pure and has to be cleaned before being used in the battery. Xiao is making a lithium battery, which is an older and less stable parent of the more common lithium ion batteries that we’re familiar with.           

Commercialized in 1991 by Sony, the lithium cobalt oxide battery created a revolution in consumer electronics by being the lightest battery and holding more charge than any competing type of rechargeable battery. To understand how this battery works, Kenneth Rosina, a graduate researcher on the team, compares the charging and discharging of the battery to an apartment of dog owners and their strange electron dogs. There are two sides, the Cathode (+) where the dog owners and dogs reside, and the anode (-), their destination when being charged. Lithium ions are the dog owners occupying the floors of the Cathode. Their dogs are electricity that we all have come to love and depend on.

            When charging an I-Pod, cellphone, or laptop, the dog owners take a direct path to the anode and never leave the battery, but the dogs, as weird as they are, always prefer take the longer path outside, eventually meeting with their owners at the anode. When the electronic device is being used, the highly charged lithium ion dog owners come back directly to the cathode and the anode crowd starts to thin, but the stubborn dogs again takes the long path through your electronic device to give it juice before meeting at the cathode again.

            Already mass-produced and used to power our electronics, Lithium cobalt oxide batteries have changed our lives but still are not perfect.  Cobalt is an expensive, rare, and toxic metal, said Dong Li, a member of the Grey Research team. “If we figure out the working mechanisms (of the cathode) and why it fails, why it works, then we have the ability to find a good material.”

            The lithium ion battery technology that consumers currently use are perfect for smaller electronics like I-Pods and laptops, but for larger, more power-hungry devices, like plug-in hybrid electric cars, the amount of energy that current commercial batteries can store per kilogram or Watt Hours Per Kilogram (Wh/kg) is simply not enough to be practical. Older rechargeable battery technologies like lead-acid and nickel-metal hydride (NiMH) contain 30-40 Wh/kg and 30-80 Wh/kg respectively. Lithium cobalt oxide batteries contain about 160 Wh/kg, enough to power an electric car anywhere from 40-150 miles per charge, depending on the size of the battery.

            In searching for a battery that could give these electric cars more range, Clare Grey’s team have proposed lithium nickel manganese oxide (Li(Ni(.5)Mn(.5))O2) as a new type of lithium-ion battery. According to Li, nickel manganese oxide is a much more durable structure that allows for many charge/discharge cycles as well as holding significantly more energy per kilogram (about 260 Wh/kg).

            If developed and commercialized to put to use into an electric car or a plug-in hybrid, it could give it as much as a third more driving range. This means a plug-in hybrid like the Chevy Volt could go from having an all-electric range of 40 miles to 55 miles, compounded by a gasoline backup recharge engine that gives the Volt up to 412 miles of total range.

           

Is it Goodenough?

            Xiao’s hands tremble.

            An only child of China’s one-children act policy, Xiao decided early in high school that it was chemistry, and not physics or biology, that tickled his fancy. His concentration is on keeping a serious and steady hand, but shuns from the stereotypical lab coat image and works on batteries in street clothes.

Xiao carefully coats a thin polymer in an electrolyte solution and places it on the lithium anode material before stacking cathode material on top. The thin polymer acts as a barrier between the two, regulating the flow of energy with microscopic holes. If the thin barrier was damaged or not placed carefully, the highly reactive lithium metal will react instantly with the copper fluoride creating an uncontrollable waterfall of energy that can cause a fire. To engineers, this is called a short circuit. To Xiao, it’s time to grab a fire extinguisher.

            It is exactly one of the problems that chemists and battery makers have tried to address. Sony and Dell have issued recalls in the last decade when a number of laptop computers seemed to spontaneously combust. It is a small number, only about three laptops out of a million have this problem, but when it happens it could be quite dangerous. An exploding Dell laptop at a Japanese conference had spectators running for safety and in another instance, an exploding Dell lit three boxes of bullets in a hunter’s truck that sent its occupants scrambling for cover.

            Despite being a miniscule scenario, Grey is interested in “identifying (what) the fundamental showstoppers are.”

            Grey has developed a method of using Nuclear Magnetic Resonance (NMR) to watch what happens in batteries in real time as they charge and discharge. The NMR is a cumbersome machine in the basement.

            “You can’t hug it.” Rosina said of its size.

It uses a magnetic field to give a clear picture of what’s going on inside a battery in real time, a rare opportunity that researchers now have.

            Amidst Stony Brook’s ongoing efforts for better lithium ion batteries, the technology of using lithium for its electrochemical properties is a national academic search that collaborates many research teams. Proposed by Professor Whittingham of Binghamton University in the 1970s, the technology has been vastly improved by a number of researchers in the field. The biggest breakthrough was the discovery of a new cathode material, lithium cobalt oxide, by John Goodenough’s research team at the University of Texas. It was the one of the first modern lithium ion battery designs commercialized for the masses.

            But in the competitive field of science and patents, things aren’t always so cooperative.

In 2004, a research team led by Yet-Ming Chiang discovered a way of using nanotechnology to give lithium-ion batteries a big performance push by boosting battery density by nearly 100 fold. Chiang his team wanted to sell the research, but Goodenough fought back, claiming they were the first to make the discovery.  Today, they are bitter rivals and struggling in an ongoing patent-infringement battle to claim honorary rights to the research.

 

The Future

            Xiao sets the new battery on a clamp and presses down with authority. He is at the last stage of his creation, pressing the two sides of the battery together. He takes an uneasy breath and releases the new coin cell from the argon chamber. He approaches a test rack where new batteries are tested for voltage and calls a colleague over to help him clamp the cell in place.

            “The voltage is a little bit high,” he says gingerly, looking at a computer chart of voltages. “Maybe it’ll short circuit.”

            Xiao’s battery is one in many on the rack also being tested. His battery would have to wait for the computer’s results.

The hybrid vehicle market in the US and on Long Island is in its infancy. To fulfill President Obama’s wishlist of achieving energy security, Asian and American car companies will have to take a gamble. Often, companies releasing a new product on the market will incur financial loss as the technology matures and people take time to warm up to it.

For a motor company starting out, initial production costs will be very high. According to Shanjun Li, an associate professor of economics at Stony Brook, an economy of scale will have to take grip of the hybrid and plug-in electric car market. The more plug-in hybrids and electric cars a factory can produce and sell, the more profitable and mature the market will become.

Xiao and his companions will continue the quest to find a better chemistry, but to Grey, success doesn’t necessarily mean selling the ideas and making lots of money.

There are other factors that pure science can never predict. Lithium Nickel Manganese Oxide are just one of many lithium-ion designs in the field, and other car companies have already began producing cars on a small scale with other lithium-ion technologies. Aside the battery market is other non-battery alternative technologies in which success will depend on the direction of the market.

“There’s three horses in the race for clean fuels,” Tonachel said. “Electricity (lithium ion batteries), hydrogen fuel, and biofuels.”

In the Stony Brook lab, the computer results came back positive and a smile breaks across Xiao’s face.

“It didn’t short circuit!”

Ahead of him is an uncertainty out of science’s hands.

Back to work.