We're increasingly reliant on our smartphones and other small devices. They connect us to the world around us and to each other. They give us directions on demand, serve up our email and text messages and let us read articles and books on any subject we type in. But all of those features require a good-size battery to make it useful.
The constant charging of our devices means we're also increasingly reliant on the grid for electricity. The search for alternative ways to power these devices is ongoing. There are plenty of great solar chargers out there, but researchers have really been aiming for a way for our devices to be human powered, harvesting our movement or heat to give our gadgets a boost.
A new flexible, wearable generator would harvest the energy from the static electricity created from our movements throughout the day. About the size of a postage stamp, the patch could be applied to the skin and generate energy from the friction of the patch against the skin when the muscles are moving underneath.
Created by the National University of Singapore, the skin patch can generate 90 volts of open circuit voltage and power of 0.8mW when tapped gently with a finger. They also tested the patch on the skin of the jaw and the forearm where the motions of speaking and fist-clenching produced 7.3V and 7.5V, respectively.
The patch consists of a 50 nm-thick gold film that acts as an electrode and sits below a silicone rubber layer covered in thousands of tiny pillars that help create more surface area for skin contact. That higher surface area creates more friction.
For now they see the patch being used as a self-powered sensor that can track the user's motion and activity, much like the fitness trackers out today. What would set it apart is that it can be applied to any area of skin and could be any size and shape to maximize comfort. It also wouldn't require any charging since it would be self-powered.
The researchers see a future where the technology could power larger devices like smart watches and even smartphones, possibly removing the need for these devices to have a battery at all.