Nanoscientists in China have developed wearable textiles that capture the energy from body movement to generate electricity to power devices as well as storing it for later use. Their wearable energy harvesting/storage hybrid self-charging power textile can be knitted into clothing and could be applied in the next generation of wearable electronics – from stress monitoring to pathogen detection, or helping track sports performance, as well as smart displays on clothing.
While there are many types of wearable electronic devices already on the market, such as smart watches, cordless headphones, and health, sport and activity monitors integrated into smartphones, their accuracy is constrained by the amount of locations on or near the body they can be placed. The flexibility and wearability of the components that provide energy to the devices is also limited, as well as being restricted to a relatively small amount of applications.
Future advanced fabrics could involve wearable electronic devices integrated into all kinds of clothing. To achieve this, such monitors, sensors, navigation systems and activity trackers need to be integrated into clothing while not being too heavy or cumbersome. As lead author Feifan Sheng of the Chinese Academy of Sciences said “Batteries are also just not very comfortable to wear. So the development of wearable and self-charging power supplies is crucial.”
As reported in Nano Research Energy [Sheng et al. Nano Res. Energy (2023) DOI: 10.26599/NRE.2023.9120079], the team therefore developed a flexible, knittable and wearable structure based on the triboelectric effect where some materials become electrically charged after coming into frictional contact with a material. Called ‘fiber-TENG’, the structure has three layers: a polylactic acid layer, a reduced graphene oxide layer, and a polypyrrole layer.
When clothing knitted from the textile is subjected to mechanical deformation such as bending or stretching, the triboelectric charges generated by the contact between the polylactic acid and reduced graphene oxide layers can be collected by the polypyrrole layer. This produces an electrical output that can work as a power generation unit. Key to the development of the fiber-TENG was the preparation of the graphene oxide fiber for use in a coaxial fiber-shaped supercapacitor – the energy storage facility integrated into the textile – which offers useful stability when bent or twisted.
Testing showed that the fiber-TENG textile offers high energy density and useful stability over many charge and discharge cycles. The team now hope to investigate uses of the textile in real-world applications by optimizing the design and fabrication process, and to assess its performance under different conditions.
“Batteries are also just not very comfortable to wear. So the development of wearable and self-charging power supplies is crucial.”Feifan Sheng
Self-charging power textile