Battery Researchers Disagree On Achievable Car Battery Capacity

Kevin Bullis of MIT's Technology Review reports on views of battery researchers on the feasibility of powering cars with batteries.

Stanley Whittingham, inventor of the first commercial lithium-ion battery and professor of chemistry, materials science, and engineering at the State University of New York, at Binghamton, says current research should make electric vehicles practical--with the following caveat: they'll probably be used for trips of less than 100 miles. Those who want 300-to-400-mile ranges typical of gasoline-powered vehicles will need to turn to plug-in hybrids: vehicles much like today's gas-electric hybrids, but with a much larger battery pack that makes it possible to go longer on electric power, thereby saving gas. These batteries could be partly charged by an onboard gas engine, but also by electricity from a wall socket. Whittingham says that while he expects battery capacity to double, it's not going to get much better than that.

But electrochemist Peter Bruce of University of Saint Andrews in Scotland thinks his experimental lithium ion battery that combines with oxygen to form lithium peroxide could more than quadruple current battery capacity.

Based on his experiments, Bruce says that such batteries could store as much as 600 to 700 milliamp hours per gram (more than four times that of batteries today) while maintaining the ability to be charged and discharged for many cycles.

Even 100 mile range would make electric cars practical for many. But to maximize the convenience of electric cars it helps to have a property that makes it easy to run a power cord to a car. Someone who parks in their own garage could plug in their car pretty easily. But someone who parks on the street and walks to an apartment will find home charging hard to do. Those who can't easily charge at home will need faster charging and higher energy storage capacity batteries to make pure electric cars practical for them.

MIT battery research Donald Sadoway (whose battery research I've previously reported on) told Technology Review in an interview in October 2005 that hydrogen fuel cells are not going to compete with batteries for vehicle power.

DS: I don't believe in fuel cells for portable power. I think it's a dumb idea. The good news is: they burn hydrogen with oxygen to produce electricity, and only water vapor is the byproduct. The bad news is: you have to deal with molecular hydrogen gas, and that's what's stymieing the research and in my opinion is always going to stymie the research. That's why I don't work on fuel cells. Where's the infrastructure? Where are we going to get hydrogen from? Hydrogen is a molecule, it's H2. To break it apart, to get H+, you've got to go from H2 to H, and that covalent bond is very strong. To break that bond you have to catalyze the reaction, and guess what the catalyst is? It's noble metals -- platinum and palladium. Have you seen the price of platinum? Lithium [for lithium ion batteries] is expensive. But it's not like platinum. Lithium right now is probably $40 a pound. Platinum is $500 an ounce. If I could give the fuel-cell guys platinum for $40 a pound, they would be carrying me around on their shoulders until the day I die.

Sadoway thinks electric cars with longer ranges are within the realm of the possible.

Batteries suitable for electric cars would make a huge difference in our energy future. Why? Simple: Batteries would allow all energy sources that can generate electricity to power vehicles. Nuclear, solar, wind, geothermal, coal will all become energy sources for transportation when batteries improve enough to make electric cars competitive.