Thomas Edison designed an electric car battery in the early 1900's that powered cars for about 20 years. The nickel-iron battery intended as an inexpensive alternative to corrosive lead-acid batteries fell out of favor over the decades. It has been revitalized by researchers at Stanford University.
Consisting of two electrodes - a cathode made of nickel and an anode made of iron - bathed in an alkaline solution, the Edison battery was slow to charge and slow to discharge. Although durable, inexpensive due to the abundance of the materials, and relatively non toxic, it proved to be inconvenient.
Walter C. Baker founded the Baker Motor Vehicle Company in Cleveland, Ohio and in 1910 ran a car powered by an Edison battery for 244-1/2 miles on a single charge. Jay Leno owns and even today drives a Baker
with an Edison battery. However, such batteries generally are used now just to store surplus electricity generated by wind turbines or obtained from solar panels.
The Stanford team has come up with a nickel-iron battery based on the Edison design that they say recharges in 2 minutes and discharges in less than half a minute. Touting the benefits of their work on the earlier battery, lead author of the study, Stanford graduate student Hailiang Wang said, “We've made it really fast.”
They accomplished this by using graphene. The new design incorporates nano-sized sheets of carbon that are only one-atom thick and multi-walled carbon nanotubes, each consisting of about 10 concentric graphene sheets rolled together. Wang said “We grew nanocrystals of iron oxide onto graphene, and nanocrystals of nickel hydroxide onto carbon nanotubes." The strong chemical bond “allows electrical charges to move quickly between the electrodes and the outside circuit,” according to Stanford chemistry professor Hongjie Dai.
For this decade's electric cars, the low cost battery would be used in conjunction with lithium-ion batteries by “giving them a real power boost for faster acceleration and regenerative braking," Wang said. “The electrolyte is just water with potassium hydroxide, which is also very cheap and safe. It won't blow up in a car." As for its charge/discharge cycle, it decays about the same as a lithium-ion battery - about 20 percent over 800 cycles.
Others involved in the project supported by Intel, a Stinehart/Reed Award, and a Stanford graduate fellowship, were from Canadian Light Source, Canada and Tsinghua University, China. They suggest that a new generation of Ni-Fe batteries could be useful as novel devices for electrochemical energy storage. More detailed information can be found in their article at Nature Communications
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