Over a century ago, Thomas Edison developed a rechargeable nickel-iron battery designed to power cars. Remarkably, the technology is still used by some people to store energy from solar panels and wind turbines. And now Stanford engineers have tweaked it to charge 1000 times faster.
Edison's original battery used a cathode made of nickel and an anode made of iron, and bathed the lot in an alkaline solution. Back in Edison's day, the conductive elements contained some carbon to help them work, but the Stanford engineers thought it would be fun to see what replacing that with graphene would do. Hailiang Wang, one of the researchers, explains to the BBC:
"In conventional electrodes, people randomly mix iron and nickel materials with conductive carbon... Instead, we grew nanocrystals of iron oxide onto graphene, and nanocrystals of nickel hydroxide onto carbon nanotubes."
Usually, Edison's battery takes hours to charge; the Stanford version takes minutes. In fact, it's 1000 times faster. Although it's still very firmly in the lab-based stages, Wang suggests that in the future they could be used alongside lithium-ion batteries in electric vehicles to give them "a real power boost for faster acceleration and regenerative braking". Is there anything graphene can't do? [Nature Communications via BBC]
Image: University of Texas at Austin