Did you always think high-performance batteries (except for the lemon-copper-zinc experiment) can only be produced in factories? I did too, until today.
Well, now a team of graduates and undergraduates from Vanderbilt University just found out a way to produce high-performance rechargeable batteries from metal scraps and a common household chemical: non-toxic, renewable, non-flammable.
The team used steel and brass, just because they’re two of the most discarded metals. The capacity of the battery they got can be compared to lead-acid batteries while charging, while discharging can be done at rates comparable to supercapacitors.
“When our aim was to produce the materials used in batteries from household supplies in a manner so cheaply that large-scale manufacturing facilities don’t make any sense, we had to approach this differently than we normally would in the research lab,” said Cary Pint, assistant professor of mechanical engineering at Vanderbilt University.
There is a secret step to doing this: anodization, a common chemical treatment that makes aluminum its matte look and colored finish. They discovered that when anodized with a common chemical, the surfaces of steel and brass turn into nanometer-sized networks of metal oxide that can store and release energy when reacting with a water-based liquid electrolyte containing potassium hydroxide, an inexpensive salt used in laundry detergent.
Surprisingly, the new home-made battery proved exceptionally stable over 5,000 consecutive charging cycles, or the eequivalent of 13 years of normal usage. Even after that much effort, the battery still retained 90% of its initial capacity.
“We’re seeing the start of a movement in contemporary society leading to a ‘maker culture’ where large-scale product development and manufacturing is being decentralized and scaled down to individuals or communities. So far, batteries have remained outside of this culture, but I believe we will see the day when residents will disconnect from the grid and produce their own batteries. That’s the scale where battery technology began, and I think we will return there,” Pint said.
The team was inspired by the Baghdad battery.
Pint also said that the aim of their project is not commercialization, but making the technology and knowledge available to the wide public and the maker community. This could be a turning point in the history of DIY.
[photo (c) Daniel Dubois, Vanderbilt University]