Wearable devices such as smart watches and electronic wristband have become increasingly popular due to their multifunctionality, encompassing health monitoring, contactless payments, and notifications.  Despite the rapid development of wearable technology, its progress is hampered by the limitations of batteries. Commonly used lithium-ion batteries lack flexibility, and their susceptibility to high temperatures poses potential safety risks, including fires and explosions.

 To overcome these challenges, NANOTEC-NSTDA and North Carolina State University collaborated on research to develop cable-shaped zinc-ion batteries for wearable devices. Their key features include flexibility, heat resistance, and environmental friendliness.

Dr. Nakarin Subjalearndee, a researcher from the Nanofunctional Fiber Research Team, initiated this research during his doctoral studies in biomedical engineering at North Carolina State University. His focus was on creating fiber-shaped energy storage devices, aiming to overcome the limitations of commonly used batteries. He eventually succeeded in developing the fabrication of graphene-based fiber electrode for cable/ fiber-shaped zinc-ion batteries.

"The current capacity of this battery is 230 mAh/g, comparable to lithium-ion coin cell batteries. This capacity is suitable for applications in wearable devices. This battery, designed as a small, flexible cable, allows product developers to freely create wearable devices without constraints," explained Dr. Nakarin. With the dual advantages of flexibility and safety, this zinc-ion fiber-shaped battery can be applied to a wide range of wearable devices, including smart watches, electronic wristbands, electronic straps, and small IoT devices.

This technology has been validated in laboratory, achieving TRL4, and is expected to be ready for commercialization within the next 6-7 years. The research team at NANOTEC is seeking potential collaborators, particularly those in the private sector, to drive further development.

“Our research findings have been reported in two articles published in Advanced Fiber Materials and ACS Applied Materials and Interfaces. A petty patent for “graphene-based fiber-shaped zinc-ion batteries and graphene-based fiber cathode fabrication process thereof” has also been filed,” Dr. Nakarin added.

Flexible, safe, and eco-friendly batteries are being researched at the global scale to support the creation of wearable devices. An ability to develop and manufacture such batteries in the country will significantly enhance Thailand’s electronics industry.