UH researchers stretching, testing, and monitoring the stretchable fabric-based Li-ion battery's performance. The gray striated section is the battery prototype. (Image: uh.edu)

The future of wearable technology just got brighter thanks to a team of University of Houston researchers that designed, developed, and delivered a successful prototype of a fully stretchable fabric-based Li-ion battery.

The idea for this Li-ion battery came from Professor Haleh Ardebili, who said, “As a big science-fiction fan, I could envision a ‘science-fiction-esque future’ where our clothes are smart, interactive, and powered. It seemed a natural next step to create and integrate stretchable batteries with stretchable devices and clothing. Imagine folding or bending or stretching your laptop or phone in your pocket. Or using interactive sensors embedded in our clothes to monitor our health.”

A major bottleneck in the development of the next generation of wearable technology embedded in fabrics is that conventional batteries are generally rigid, leading to limited functionality — and they use a liquid electrolyte — raising safety concerns. The traditional organic liquid electrolytes are flammable and can lead to explosions.

The key to the breakthrough is the use of conductive silver fabric as a platform and current collector.

Another type of bendable/stretchable polymer battery prototype being developed in the UH lab of Haleh Ardebili, Bill D. Cook Professor of Mechanical Engineering at the University of Houston. (Image: uh.edu)

“The woven silver fabric was ideal for this since it mechanically deforms or stretches and still provides electrical conduction pathways necessary for the battery electrode to function well. The battery electrode must allow movement of both electrons and ions,” said corresponding author Ardebili.

“I was interested in understanding the fundamental science and mechanisms related to stretching an electrochemical cell and its components,” she said. “This was an unexplored field in science and engineering and a great area to investigate.”

“Although we have created a prototype, we are still working on optimizing the battery design, materials and fabrication,” Ardebili said.

Ardebili is optimistic that the prototype for a stretchable fabric-based battery will pave the way for many types of applications such as smart space suits, consumer electronics embedded in garments that monitor people’s health, and devices that interact with humans at various levels. There are many possible designs and applications for safe, light, flexible, and stretchable batteries, but there is still some work to be done before they are available on the market.

“Commercial viability is all about cost and scale,” Ardebili told Tech Briefs in an exclusive interview, the entirety of which can be read below. “There is indeed a clear need for such batteries in future stretchable electronic devices. As those products get commercialized, I suspect this battery will too. I expect a timeline of about a decade.”

Whether the stretchy batteries end up powering spacesuits or workout clothes or some other innovative application, Ardebili wants them to be reliable and safe. “My goal is to make sure the batteries are as safe as possible,” she said.

Here is the Tech Briefs interview — edited for length and clarity — with Ardebili.

Professor Haleh Ardebili (right) and Navid Khiabani, a UH graduate research assistant, discussing bendable batteries. (Image: uh.edu)

Tech Briefs: I’m sure there were too many to count, but what was the biggest technical challenge you faced while developing this prototype?

Ardebili: Yes, there were many challenges. This project in particular took more than five years to reach this current state. A key impediment was the integration of the fabric with the battery functionality.

Tech Briefs: Can you explain in simple terms how it works?

Ardebili: In this battery, the electrochemical active material that provides charge through lithium bonding and debonding (intercalation), is coated and deposited on a silver stretchable fabric. As the lithium ions shuttle back and forth inside the battery between the negative and positive electrodes, the battery is also capable of stretching simultaneously due to the stretchability of the fabric and polymer electrolyte.

Tech Briefs: The article I read quotes you as saying, “Although we have created a prototype, we are still working on optimizing the battery design, materials, and fabrication.” How is that coming? Any updates you can share?

Ardebili: Although we have a prototype, there is always an impetus to increase the performance and efficiency of the battery. Think back to our older laptops or phones. Once charged, they would lose their capacity quickly. Newer models can last much longer without being charged. We are tweaking the design precisely to achieve large capacity and longer life. The work is painstaking, but we are making progress.

Tech Briefs: Going from that, what are your next steps? Any future research/work/etc. on the horizon?

Ardebili: We are working on other types of flexible and stretchable batteries with different materials that bend, deform, and stretch while providing energy and power.

Tech Briefs: Do you have any advice for engineers aiming to bring their ideas to fruition?

Ardebili: If you have a vision for an interesting device, concept, or product, don’t give up no matter how hard it seems to realize it. Almost all of the most sensational inventions were considered “impossible” just prior to someone making them a reality.

Tech Briefs: Anything else you’d like to add?

Ardebili: I firmly believe that the ‘science-fiction-esque’ future of our world will be predicated on just a few important fields. To name just a few: AI and stretchable/flexible electronics. I hope we have made a small dent in this quest.