The device is elastic enough that you can wear it as a ring, bracelet, or any other accessory that touches your skin. It also harnesses a person's natural heat - employing thermoelectric generators to convert internal body temperature into electricity.

"In the future, we want to be able to power your wearable electronics without having to include a battery," said Jianliang Xiao, senior author of the new paper and associate professor in the Paul M. Rady Department of Mechanical Engineering at the University of Colorado.

The concept may sound like something out of the movie series Matrix Xiao and his colleagues are not so ambitious: their devices can generate about 1 volt of energy for every square centimeter of surface area - less voltage per area than most existing batteries provide, but still enough to power electronic devices like watches orfitness trackers.

Scientists have experimented with similar thermoelectric devices before, but Xiao's is elastic, can heal itself when damaged and is fully recyclable, making it a cleaner alternative to traditional electronics.

"Every time you use a battery, you are draining the battery and eventually you will need to replace it," Xiao said. "The good thing about our thermoelectric device is that you can use it and it provides constant power."

High Tech

The project is not Xiao's first attempt to fuse human with robot. He and his colleagues have already experimented with designing "electronic skin," wearable devices that look and behave very similar to real human skin. This android epidermis, however, needs to be connected to an external power source to function.

So far. the group's latest innovation starts with a base made of an elastic material called polyimine. scientists then place a series of thin thermoelectric chips on that base, connecting them all with liquid metal wires. the end product looks like a cross between a plastic bracelet and a miniature computer motherboard or perhaps a modern diamond ring.

"Our design makes the whole system stretchable without introducing too much stress to the thermoelectric material, which can be very brittle," Xiao said.

Pretend you're out for a run. As you exercise, your body heats up, and this heat radiates out into the cold air around you. Xiao's device captures this energy flow instead of wasting it.

"Thermoelectric generators are in close contact with the human body and can use heat that would normally be dissipated into the environment," he said.

Lego Blocks

He added that you can easily increase that power by adding more generator blocks. In that sense, he compares his design to a popular children's toy.

"What I can do is combine these smaller units to get a larger unit," he said. "It's like putting a bunch of small Lego pieces together to make a big structure. It offers a lot of customization options."

Xiao and his colleagues calculated, for example, that a person taking a brisk walk could use a device the size of a typical sports wristband to generate about 5 volts of electricity - which is more than many watch batteries can muster.

Like Xiao's electronic skin, the new devices are as tough as biological tissue. If your device tears, for example, you can put the broken ends together and they will seal themselves in just a few minutes. And when you're done using the device, you can place it in a special solution that will separate the electronics and dissolve the polyimine base-eachof these ingredients can be reused.

"We are trying to make our devices as cheap and reliable as possible, while making as close to zero impact on the environment as possible," Xiao said.

Although there are still design flaws, he thinks his group's devices could be on the market in five to ten years. Just don't tell the robots, we don't want them to come up with ideas.

The scientific paper was published in Science Advances, with information from University of Colorado.