Kirigami papercut-inspired device can be recharged simply by squeezing
In a move towards gadgets that can be charged without a plug, researchers have developed a novel self-charging device - inspired by the intricate art of papercutting - which can power low-energy devices.
Despite the advances that have been made in portable electronic devices–brighter displays, better cameras and faster connections – our gadgets are still held back by a fundamental flaw: eventually, they will need to be plugged in to charge.
Over the past few years, new technologies such as portable power banks or wireless charging systems have appeared on the market to help free our devices from the plug socket, with varying success. Countless startups have been emerging which promise technology which harnesses energy from radio waves, movement, or other sources to charge our devices.
Professor Zhong Lin Wang of the Georgia Institute of Technology and his collaborators chose to focus their project on mastering the capture of mechanical energy: the energy of motion.
Professor Wang, who has been working on this process for several years, had already created “triboelectric nanogenerators” (TENGs). These are devices which harness mechanical energy, such as that created with our steps or the rotations of a car tyre, and use it to power portable electronics.
While the TENGs showed promise in utilising this otherwise wasted energy, they took several hours to charge small electronics and are inconveniently made from heavy acrylic.
To address these drawbacks, the researchers began work on a more efficient, lightweight design. They took inspiration from the traditional art of papercutting, using an interlocked diamond-shaped Kirigami (Japanese papercut) pattern.
The art of papercutting has been practised since the invention of paper in China in the early second century AD and has a long tradition as an art form in China and Japan.
By coating the device with different materials, the researchers transformed it from a decorative object to a power unit. The four outer sides are made from gold and graphite-coated sand paper. This forms the supercapacitor element, which stores energy. The inner surfaces were coated in a thin layer of gold and fluorinated ethylene propylene film; comprising the TENG energy harvester.
The complete device is ultra-light and measures just a few inches long.
The researchers found that pressing and releasing the device for a few minutes charged it to 1V; enough to power a low-energy device such as a remote control, temperature sensor or watch.