Energy harvesting is a process that converts ambient energy into electrical energy to power electronic devices. The required electrical energy for these devices can be harvested from various other forms of energy, including mechanical stress such as strain or displacements, heat energy, as well as thermal gradients and incident light (photovoltaics). Classic examples include the energy harvested from wind turbines, or from the sun via solar panels fixed to the top of buildings. However, harvesting energy within textile applications is much less common due to the challenges associated with incorporating the appropriate materials within a fibrous material during the manufacturing process [1].

Wearable electronics and smart textiles such as the Fitbit and heated clothing have become increasingly commercially prevalent. However, most wearables on the market are powered by a battery pack that needs to be replaced or recharged. Also, these items are often ridged, bulky and problematic when it comes to washing as the battery pack needs to be removed beforehand. However, researchers have recently found the development of textile energy harvesting to be a viable, lightweight, comfortable and flexible replacement for batteries where the fibres themselves become the energy harvesting material, removing the requirement of a battery pack for the fabrication of truly wearable, electronic and smart textiles [1].

The incorporation of energy harvesting devices into a textile material aids a mechanism to draw electricity from external energy sources such as body heat, movement and motion. The piezoelectric effect is a notably promising approach that can convert small movements into great electrical potential by generating an electrical voltage when the material experiences pressure or stretching. Piezoelectricity is a consequence of a shift in the charge distribution within the material caused by deformation.

In this product innovation profile, WTiN reports on a novel solution developed by researchers at Chalmers University of Technology, Sweden, together with the Swedish School of Textiles in Borås and the research institute Swerea IVF. The researchers have created a textile material that can transform kinetic energy into electricity. The resulting material was found to have a surge in the electricity generated with an increase in the applied force and moisture to the material. Furthermore, this intelligent textile can be treated as a conventional material in everyday life; the material can withstand washing similar to conventional fabrics and maintains functionality after exposure to conditions such as sweat, ambient humidity and rain – setting this novel development apart from other textile generators that commonly short circuit under these practical conditions [2].