You get home from work, walk the dog, fix dinner, watch TV — but wait. Don’t forget to plug in the car before you go to bed.
This scenario could become a reality within a couple of years. Toyota plans to test-market a fleet of “plug-in” electric cars by late 2010. GM’s Chevy Volt, a rechargeable vehicle under development, will cover up to 40 miles — well within commuting range for many. These cars can then be recharged through a simple overnight plug-in.
If you drive more than the battery can handle in one charge, no sweat. That’s when the internal combustion engine kicks in. Or maybe you’ll be driving a battery-operated car with a generator on board for back-up power.
Gerbrand Ceder, MIT professor of materials science and engineering, is doing his part to realize the promise of plug-ins. “The plug-in concept is so important because driving patterns in the US support it. With even a 20-mile range, you can do 50 percent of all your driving,” he says. “This is not a pipe dream. The battery technology is there to make this happen. GM, Volvo, Mercedes, Nissan — they’re all working on it.”
Ceder is talking about lithium-ion battery technology. A research breakthrough by Ceder and colleagues at MIT is leading to high-capacity battery materials that could make a significant dent in fossil fuel consumption and help make renewable energy sources a reality. Ceder’s work is part of ongoing research at MIT seeking technological solutions to the energy crisis.
Researchers at MIT have developed lithium nickel manganese oxide electrodes for a new type of battery that offers a charge-discharge rate considerably better than lithium cobalt oxide (LiCoO2), the current battery electrode material of choice. Scientists knew that lithium nickel manganese oxide could store a lot of energy, but the material took too long to charge to be commercially useful. The MIT researchers set out to modify the material’s structure to make it capable of charging and discharging more quickly.
Using a computer model, Ceder showed that under conditions of high power, disorder in the lithium nickel manganese material caused it to compress and trap the lithium ions that allow electricity to flow.
Ceder’s laboratory structured a new material with a very ordered crystalline structure, allowing lithium ions to flow freely between the metal layers of nickel and manganese. Besides one day replacing the batteries used in hybrid cars on the road today, the new material could advance plug-in hybrids that run completely from electricity stored from an overnight charge.
Ceder has created an even faster-charging material by modifying an existing lithium ion phosphate. In addition to being four or five times lighter than existing battery packs for plug-ins, the material can be fully discharged and recharged in less time than it takes to read this sentence. “We can take all the power in or out of our battery in 10 seconds,” Ceder says. “You put that in a Prius and it accelerates like a Ferrari.”
The lithium nickel manganese oxide batteries would be less expensive and more stable than lithium cobalt oxide cells. But before the material can be used commercially, the manufacturing process needs to be made less expensive, and a few other modifications will likely be necessary, Ceder says.
In research taking place outside MIT, nanotechnology is being exploited to make anodes reportedly capable of holding 10 times the charge of conventional versions. Ceder says this will require a cathode — the terminal where current flows out of the battery — that also holds 10 times the charge. However, he adds, materials science may once again come to the rescue. Advances in materials are allowing battery-makers to reduce the weight and volume of the anode, the terminal where current flows in, and add more cathode material in its place.
Meanwhile, Ceder is refining his computer model to help other researchers develop new materials for a wide variety of technological advances in the energy field, which will take a materials revolution to replace the high energy density of fossil fuels. His goal is to quickly and efficiently find unique new materials that could revolutionize next-generation solar cells, batteries and more.
Sound futuristic? “We’re at MIT,” Ceder says. “We want to be at the head of the curve.”