Small, flexible generators that convert movement into electricity could soon be the future of free and unlimited energy, thanks to a breakthrough in energy harvesting technology.

Scientists from Loughborough University and the University of Surrey in the UK have created a unique device based on triboelectric nanogenerators (TENGs), which generate electricity from motion – in much the same way static electricity is produced.

Until now, using TENGs has been incompatible with many day-to-day electronic devices due to their inability to produce a constant current.

But a team of researchers, led by Dr Ishara Dharmasena of Loughborough’s School of Mechanical, Electrical and Manufacturing Engineering, in collaboration with the Advanced Technology Institute of the University of Surrey, has found a way to produce a direct current (DC) from a unique TENG design, creating a steady flow of electricity and opening up the potential for real-world applications.

We spoke to Dr Dharmasena, who explained this breakthrough.

How long have you been conducting research into this technology?
I’ve been working on this since the beginning of my PhD project, in early 2016.

What have the challenges been in making TENGs compatible with everyday electronic devices?
The main drawback of TENG, to date, has been discontinuous and unpredictable outputs. Because of this issue, we can’t use TENGs to directly power electronic devices – you need additional circuits to manage the current, and, sometimes batteries to store electricity. This meant the effectiveness and applicability of the technology in real life situations was drastically reduced.

What was the breakthrough?
Instead of using a single TENG device to generate a discontinuous current signal, in this new design, we’re using a collection of TENG units to directly produce a DC current signal, which is a current output similar to a regular battery.

This way, we can get rid of additional electronic circuits, batteries, etc, and directly use TENG devices to power practical applications.

How can this technology be used in fitness, sports and health products?
This technology could be very useful in next generation wearable and implantable electronics, which measure fitness and healthcare information. For example, the power generation capability of these devices could be useful in powering existing electronics, such as smart watches, motion sensors, activity monitoring units, heart pulse sensors, physiological sensors and, potentially, mobile devices.

Another special feature of TENG is that it can act as a self-powered sensor; in other words, a sensor that can generate its own power to provide information like movement, position, etc. This could be massively useful for monitoring things like our physical activity, speed and pulse.

TENGs are being extensively researched for their compatibility with emerging technologies such as Internet of Things (IoT) and 5G-related applications, which will also provide unparalleled advantages to sports and healthcare products.

In what other ways could it improve and evolve these products?
TENGs can be constructed using flexible and stretchable polymers (plastics), which are similar to our clothing. They can also act as a secondary skin.

Since TENGs can be constructed using low-cost, waste plastics and simple manufacturing techniques, they are cheap and non-toxic. Whereas conventional battery-related power supplies are rigid, bulky, expensive and contain toxic materials.

With TENGs, health and fitness products can be made more sustainable, durable, low-cost, wearable and autonomous.

How will TENGs impact the Fit Tech market?
In future, technologies that provide self-powered operation of fitness and health-related applications will enable a number of unique benefits.
For instance, they will enable technologies such as remote health detection and monitoring. Without external intervention, the self-powered systems will be able to continuously monitor the health or exercise related parameters of a person and transmit the relevant data to doctors, trainers, etc.

Furthermore, they would potentially be able to power the sensors and medical devices implanted in our bodies, enabling their long-term operation, without needing to be recharged or replaced.

How soon will they be used by consumers?
The technology is still in its early stages. However, my vision is to produce a textile-based working prototype of a wearable health monitoring system within the next three years.

If things go according to the current plan, consumers will be able to benefit from this technology in the next three to five years.