The new research was done by the students of University at Buffalo and the Chinese Academy of Sciences might enable us one day to leave our chargers home and recharge our phones by using body movements only. The researchers have developed a triboelectric nanogenerator in the form of a small metal tab that can generate electricity from simple body movements such as bending of a finger. The tab uses the triboelectric effect which sees some materials producing electric charge through friction with another material.
Most of the everyday static electricity falls under the triboelectric banner. In the case of the tab, the two materials used are gold and polydimethylsiloxane (PDMS). A thin layer of gold is surrounding a layer of the PDMS. When one of the gold layers is stretched and released, it crumples and creates a mini mountain range like structure. When the device is bent again, the friction created between the gold and PDMS layers produces an electric charge. The co-lead author Yun Xu from Chinese Academy of Sciences said, “This causes electrons to flow back and forth between the gold layers. The more friction, the greater the amount of power is produced.”
The device is very small and measures only 1.5cm (0.6-inches) in length and 1cm (0.4-inches) in width. Even though it is small, it can still deliver a maximum voltage of 124-volts, a maximum current of 10 microamps and a maximum power density of 0.22 milliwatts per sq cm. This is not enough to charge a smartphone, however, it is enough to light up 48 LED lights simultaneously. The team says that their product is cost effective and simple to manufacture. “No one likes being tethered to a power outlet or lugging around a portable charger. The human body is an abundant source of energy. We thought: ‘Why not harness it to produce our own power?”
The team is looking to improve the performance by using large pieces of gold. They are also working on a portable battery which can store energy produced by the tab.