Improvements to battery chemistry inspired by nickel-iron designs developed more than 120 years ago could be used in energy storage today, according to a study by University of California (UCLA). 

UCLA researchers have developed a nickel-iron battery prototype that charges in seconds and works for more than 12,000 cycles, equivalent to more than 30 years of daily recharging. 

They built the technology from tiny clusters of metal, then embedded them in an ultra-thin carbon-based conductor to make electrodes – inspired by the chemistry used by Thomas Edison in his early-1900s nickel-iron battery concept. Edison hoped the technology could provide electric cars with faster recharging and greater range than the lead-acid batteries of the time, but his designs became obsolete as petrol cars began to dominate. 

While the UCLA team improved on the original concept’s charging speed, output and durability, its battery does not match the storage capabilities of the lithium-ion batteries used in today’s electric vehicles. However, its Edison-inspired battery could find a use in other areas, such as storing excess electricity generated at solar farms or providing backup power at data centres.

Maher El-Kady, an assistant researcher in the UCLA Department of Chemistry and Biochemistry and co-author of the study, said: “Because this technology could extend the lifetime of batteries to decades upon decades, it might be ideal for storing renewable energy or quickly taking over when power is lost. This would remove worries about the changing cost of infrastructure.”

To create the technology, the team used proteins that were byproducts of beef production as templates for growing tiny clusters of nickel for positive electrodes, and of iron for negative electrodes. According to the researchers, the nooks and crannies in the folded protein structure limit the metal clusters’ size to fewer than five nanometers – so small that 10,000 to 20,000 clusters would fit within the width of a human hair.

The proteins were then combined with graphene oxide, an ultra-thin 2D material that is just one atom thick. This mixture was superheated in water and then baked at a high temperature, converting the proteins into carbon and embedding the tiny metal clusters into its structure. The resulting aerogel formation is made up of almost 99% air by volume.

Because the structure’s outer surface is so thin and porous, it provides surplus space in which battery chemistry reactions can take place. As the metal particles shrink into nanoclusters, the surface area-to-volume ratio increases – “a huge advantage for batteries”, El-Kady said. “When the particles are that tiny, almost every single atom can participate in the reaction. So, charging and discharging happen way faster, you can store more charge, and the whole battery just works more efficiently.”

This nanocluster fabrication technique may seem complex, but the researchers have said that their approach is deceptively straightforward and inexpensive. “We are just mixing common ingredients, applying gentle heating steps and using raw materials that are widely available,” said El-Kady.

The team’s next step is to explore using other metals in this fabrication technique. It is also looking at possible replacements for bovine proteins, such as natural polymers that are more abundant, which would offer a more cost-effective way to scale the technology for future manufacturing.

The study, ‘Protein-templated Fe and Ni subnanoclusters for advanced energy storage and electrocatalysis’, has been published in the journal Small.