For many of us, green tea is best enjoyed as a soothing, warm drink, but now it may be leaving the dining table and joining the world of wearable electronics.
Scientists have developed a flexible, compact and rechargeable energy storage device for wearable electronics using green tea polyphenols, according to a new study published in The Journal of Physical Chemistry C.
Powering wearable electronics with a long-lasting source of energy is still a challenge in the industry.
“Our objective is to fabricate wearable electronic devices. Compressible energy storage devices are the first step towards achieving that objective,” said Kothandam Krishnamoorthy, from the CSIR-Network of Institutes for Solar Energy.
Supercapacitors — devices that store and regulate energy — are clunky, and compressible ones have run into many problems. They are usually made with carbon-coated polymer sponges, which tend to bunch up and weaken their performance.
The researchers hope this new breakthrough can overcome this roadblock.
“If you brew green tea and leave it for a while in a glass, you will see a coating. The coating comprises polyphenols, which are the antioxidants in green tea. They are capable of reducing metal ions such as silver,” said Krishnamoorthy. “We could use polyphenols in green tea to prepare metal coated sponges that are essential for the fabrication of compressible supercapacitors.”
To prepare their new energy storage device, scientists created polymer gels in green tea extract. The gels were infused with polyphenols, natural compounds found in different foods that also have antioxidant properties. Eventually, the resulting supercapacitor produced enough energy to power a heart rate monitor, LEDs or a Bluetooth module. It even performed well after the device was compressed more than 100 times.