Portable electronic devices usually draw their power from conventional rechargeable batteries, but Zhong Lin Wang, Chenguo Hu and their colleagues wanted to see if they could harvest energy from a user’s body movements. Wang and others have been working on this approach, creating triboelectric nanogenerators (TENGs). However, most TENGs take several hours to charge small electronics, such as a sensor, and are made of acrylic, which is heavy.
So the researchers turned to a rhombic paper-cut design a few inches long and covered it with different materials to turn it into a power unit. The four outer sides – made of gold and graphite coated sandpaper – comprised the energy-storing supercapacitor element, while the inner surfaces – made of paper and coated in gold and a fluorinated ethylene propylene film – comprised the TENG energy harvester.
Pressing and releasing the device over just a few minutes is said to have charged the device to 1V, enough to power a remote control, temperature sensor or a watch.