Could a century’s old battery technology be the wave of the future for helping in electric vehicle energy storage? That’s what researchers at Stanford University are betting, turning to a design by Thomas Edison for inspiration.
Electric cars today are mostly powered by lithium ion batteries, but back in Edison’s day nickel-iron batteries were the rage. Mostly out of favor by the 1970s because of technological limitations, it could now be making a comeback via enhancements that dramatically increase its ability to both charge quickly and discharge power rapidly.
Researchers say they’ve created what they term an “ultrafast” nickel-iron battery that reportedly can be charged in about two minutes and discharge its energy in less than 30 seconds. They accomplished this, they say, through the use of graphene – nanosized sheets of carbon that are only 1-atom thick – and multi-walled carbon nanotubes to greatly enhance the electrical conductivity in electrodes, which is a key feature of Edison’s original battery design of two electrodes – a cathode made of nickel and an anode made of iron – bathed in an alkaline solution.
“In conventional electrodes, people randomly mix iron and nickel materials with conductive carbon,” said Stanford Hailiang Wang in a statement. “Instead, we grew nanocrystals of iron oxide onto graphene, and nanocrystals of nickel hydroxide onto carbon nanotubes.”
The technique used to do this, according to Stanford, “produced strong chemical bonding between the metal particles and the carbon nanomaterials, which had a dramatic effect on performance” to the tune of nearly 1,000 times for the charging and discharging rates.
“Coupling the nickel and iron particles to the carbon substrate allows electrical charges to move quickly between the electrodes and the outside circuit,” said Hongjie Dai, Stanford professor of chemistry. “The result is an ultrafast version of the nickel-iron battery that’s capable of charging and discharging in seconds.”
Now before you go out and invest in nickel-iron batteries for your Nissan Leaf, realize this research is only small scale at this point – the fine folk at Stanford so far prototyped just a 1-volt battery with enough power to run a flashlight. That’s a far cry from the type of energy needed to drive an electric vehicle. Also, if this technology does scale, it won’t replace lithium-ion batteries, but likely supplement them instead, especially in emergency situations.
“Our battery probably won’t be able to power an electric car by itself because the energy density is not ideal,” Wang said. “But it could assist lithium-ion batteries by giving them a real power boost for faster acceleration and regenerative braking.”
The researchers are now looking at ways to make a bigger battery that could be used for the electrical grid or transportation.