Today’s battery technology is adequate for electric vehicles with a range of more than 200 miles, but the batteries are still very expensive and require elaborate safety mechanisms. There are also concerns that they won’t last long enough to be attractive to most consumers.
But current research will double energy-storage capacity while also increasing the lifetime of batteries, improving safety, and cutting costs more than enough to make electric vehicles and plug-in hybrids practical for the mass market. At least these were the predictions of researchers presenting their latest work at the Materials Research Society (MRS) meeting in Boston this week. And although many significant challenges remain, an experimental type of rechargeable battery that’s like a fuel cell could increase battery storage that much more.
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. The real advances in batteries, he says, won’t be in energy capacity, but in safety, longevity, and cost. If electric vehicles are to be widespread, one of the most important goals of battery research must be to replace the cobalt now used in the lithium-ion batteries found in cell phones and laptops. “There’s just not enough [cobalt] in the world,” says Whittingham, who is working on mixed-metal electrodes, which require little to no cobalt.
One promising new type of battery, which actually has lower storage capacity than today’s lithium-ion batteries, could nevertheless prove a boon to plug-in hybrids. Lithium iron phosphate batteries use iron, a very cheap metal, instead of cobalt, and they have an inherently safe chemistry (see “Safer Lithium-Ion Batteries”). What’s more, they operate at a lower voltage that will extend the life of the electrolyte, and therefore the battery.