Stanford University scientists are looking to the past to answer the present's need for energy storage technologies, by upgradinga rechargeable battery technology developed a century ago by Thomas Edison – nickel-iron.

Nickel-iron batteries were used to power the electric cars of the era and were also used as backup power for railroads and mines. Edison developed the battery as an inexpensive alternative to the corrosive lead-acid batteries of his day.

But despite being relatively inexpensive, the nickel-iron battery has a big drawback – it can take hours to charge. The Stanford team thus added carbon into the mix to increase the electrical conductivity of the electrodes.

Graphene and carbon nanotubes were added to the make-up of the Stanford battery's electrodes. Nanocrystals of iron oxide were grown on graphene while nanocrystals of nickel hydroxide were grown on the carbon nanotubes.

The scientists found that the new make-up of the anode and cathode resulted in an increase in the speed by which electrical charges moved between electrodes, giving the battery a faster charging and discharge rate.

Using their new electrodes, the team has developed a 1-volt prototype battery that can be fully charged in about 2 minutes and discharged in less than 30 seconds. This is just enough power to operate a flashlight and the researchers would need to scale up the technology before it could be used to store renewable energy or for transportation.

"It's definitely scalable," said Stanford graduate student Hailang Wang. "Nickel, iron and carbon are relatively inexpensive. And the electrolyte is just water with potassium hydroxide, which is also very cheap and safe. It won't blow up in a car."

The researchers are looking to improve on the battery's ability to hold charge over time. Currently the battery decays about 20 percent over 800 cycles. Slowing down or eliminating the rate of decay would be key to the battery's long-term performance.

The updated version from Stanford is also seen as an alternative to lithium-ion batteries. – EcoSeed Staff