Wearable Devices Could Be Powered by Your Body’s Mechanical Energy

A new nanogenerator developed by researchers in the US and China could be used in the future to power wearable devices. According to the study – which was published in the journal Nano Energy – the gold-based nanogenerator could convert mechanical energy into electrical power.

The gold tab – known as a triboelectric nanogenerator – can be attached to the skin and store enough energy to power a device. The technology uses small bodily movements – such as bending a finger – to generate energy.

“No one likes being tethered to a power outlet or lugging around a portable charger,” said author Dr. Qiaoqiang Gan, associate professor of electrical engineering in University at Buffalo’s School of Engineering and Applied Sciences. “The human body is an abundant source of energy. We thought: ‘Why not harness it to produce our own power?’”

The principle behind triboelectric charging involves friction between two different materials. For example, the static electricity generated when a person drags their feet across a carpet is often the result of this triboelectric effect.

While research teams have previously tried to harness the triboelectric effect to power devices, nanogenerators designed for this purpose are often expensive and complex to produce. But Gan and his team have attempted to address both of these issues with their nanogenerator.

The triboelectric nanogenerator detailed in the current study is made up of a polydimethylsiloxane (PDMS) – a polymer used to make contact lenses – sandwiched between two thin layers of gold. One of the gold layers is stretched more than the other, allowing it to crumple and contract when held straight. This allows for the generation of triboelectric energy due to the friction between the gold and the PDMS when the device is manipulated.

“This causes electrons to flow back and forth between the gold layers,” said senior author Dr. Yun Xu, professor of Institute of Semiconductors (IoP) at Chinese Academy of Science. “The more friction, the greater the amount of power is produced.”

The device measures 1.5 cm by 1 cm and has a maximum output of 124 volts. While this is not enough to charge a smartphone in a small period of time, it was capable of simultaneously powering 48 red LED lights.

The team is now working on increasing the electricity generation abilities of the nanogenerator by using larger pieces of gold that have been stretched and folded into a different conformation. A specialized portable battery is also in the works to store the energy generated through the triboelectric effect to power diverse wearable devices.