Wearable textile developed that captures energy from body movement to power devices

Scientists have succeeded in developing a wearable fabric that can convert body movement into usable electricity and even store it. If advanced fabrics can be developed, then perhaps in the future wearable electronic devices integrated into shirts, pants, underwear, and hats.
These wearable will be able to track indicators of frailty to assess the risk of age-related disease, monitor cortisol levels to track stress levels, or even detect pathogens as part of a global pandemic monitoring network. The fabric potentially has a wide range of applications from medical monitoring to assisting athletes and their coaches in tracking their performance, as well as smart displays on clothing.

The research team responsible for the textile describes how it works in a paper published in Nano Research Energy.

The accuracy of such sensors remains limited due to the handful of locations on or near the body where they can be placed and restricted to a small window of applications compared to the ambitions of many health and sporting specialists for such technology.

A range of health, sport, and activity monitors are now integrated into smartphones.

To take wearable electronics to the next level, integrating health monitors, sports sensors, navigation systems, and activity trackers into clothing in a way that is lightweight, unobtrusive, and less cumbersome still requires some breakthroughs in advanced textiles.

The challenges of existing wearable electronics include limitations in the flexibility and thus wearability of the components that supply energy to the devices.

In addition, energy supply units need to be easily integrate with the devices and, in an era of increased environmental awareness, sustainable. On top of all this, existing energy storage technologies have very limited capacity.

Batteries are also just not very comfortable to wear, which is why the development of wearable and self-charging power supplies is crucial.
Nanoscientists produced a “fiber-TENG,” which is a flexible, knittable, wearable structure that takes advantage of the triboelectric effect, in which certain materials become electrically charged after coming into frictional contact with another, different material.

The fiber-TENG consists of three layers: a polylactic acid layer (a type of polyester commonly used in 3D printing), a reduced graphene oxide layer (a highly affordable type of graphene), and a polypyrrole layer (a polymer already widely used in electronics and medicine).
When the fiber-TENG is subjected to mechanical deformation, such as bending or stretching by the person wearing a piece of clothing knitted from the textile, the triboelectric charges generated by the contact between the polylactic acid and reduced graphene oxide layers can be collected by the polypyrrole layer. This process generates an electrical output that can be used as a power generation unit.

Key to the development of the fiber-TENG was a novel process used to prepare the graphene oxide fiber for use in a coaxial fiber-shaped supercapacitor (fiber-SC)—the energy storage facility integrated into the textile. A coaxial structure provides great stability when bending and twisting.

The process involves adding active materials (those that can store and release electrical energy) onto the surface of reduced graphene oxide (rGO) fibers.

First, the researchers produced the rGO fibers via an application of hydroiodic acid. Then, they add two active materials, manganese dioxide.

Testing their fiber-TENG textile, the researchers found that it enjoys high energy density and lengthy stability overcharge and discharge cycles, enhancing its promise in delivering wearable energy generation and storage.