Energy-Harvesting Smart Floors Are Made Possible By Spongy Wood Nanogenerators

Mar, 2021 - by CMI


The novel wood sponge generator could be used as both energy-harvesting flooring materials and wearable sensors

Untold amounts of resources are available everywhere around us if we can just find out a way to access them. Researchers from ETH Zurich and EMPA in Switzerland have now experimented a sustainable method of producing spongy wood flooring that generates electricity with each phase.

The piezoelectric effect is used to operate the material. Positive and negative charges separate to opposite surfaces when the material is squeezed under mechanical stress, resulting in a voltage when paired. The theory goes that if one makes flooring using these materials, they can extract energy from people walking on them. PaveGen's pavement tiles and soccer pitches that control their own lights are examples of this concept in motion. Energy-harvesting floors that are similar use the triboelectric effect, which generates electricity when nanofibers rub against each other.

Researchers from ETH Zurich and EMPA looked into the piezoelectric potential of wood, a popular building material. It is not normally flexible enough to produce a lot of electricity, so the team devised a way to make it more so. The wood was subjected to a method known as "delignification." Lignins are natural polymers that work as structural support in plant cells, especially in wood and bark, keeping them stiff and solid. The wood became much spongier after some of the lignins were extracted, allowing it to be easily squeezed and gain its original shape when the strain was released.

This type of wood sponge generator, according to the report, could be used as both energy-harvesting flooring materials and wearable sensors. Other applications, such as wood that glows under UV light, were demonstrated in a recent report. The results were published in the ACS Nano and Science Advances journals.