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Shizuoka institute develops storage batteries made with coffee grounds

Kyodo

An institute in Shizuoka Prefecture has been working on a storage battery that uses activated charcoal made with coffee grounds, focusing on the environmental and cost benefits of using recycled waste.

“It is as efficient as ordinary activated charcoal. I hope it will be used for a wide variety of purposes,” said Keisuke Kikuchi, a senior researcher at Industrial Research Institute of Shizuoka Prefecture.

Activated charcoal, which has many microscopic holes on the surface, can store electricity when it is soaked in an electrolyte solution. The finer the holes and the wider the surface area, the more electricity it can store. Storage batteries are widely used in factories for emergency backup power during blackouts.

Activated charcoal is also used to deodorize air and clean water, as it adsorbs various substances.

On the other hand, it is hard to increase production because palm trees are the major source of activated charcoal and increasing their harvest would lead to destruction of tropical forests.

Shizuoka, which hosts numerous factories run by major beverage makers, ranks third in coffee beverage shipments. Every year, some 4.3 tons of coffee grounds are generated in the prefecture, but these are discarded because they are not suitable as feed or fertilizer.

A research team led by Kikuchi found that coffee grounds contain a lot of carbon and are filled with many fine holes similar to those in activated charcoal. The team created a power storage system using two thin sheets of plates made with charcoal processed with coffee grounds.

The institute’s plan has merit because the coffee grounds are virtually free and the supply is stable. The storage batteries retain their power and can be used quickly, making them suitable during natural disasters. The institute has already received queries about potential uses from companies inside and outside the prefecture.

“I want to make the batteries more widely used as environmentally friendly technology, using unused domestic material,” Kikuchi said, adding that he is now gearing up for studies on mass production.