Mar 18, 2021 09:00:00

The technology to generate electricity by applying pressure to wood turned out to be 55 times more effective just by rotting the wood

On March 10, 2021,

Jianguo Sun, a materials scientist at the ETH Zurich , said that the technology to generate electricity by applying pressure to wood can be expected to improve its effect by rotting the wood. Was announced.

Enhanced mechanical energy conversion with selectively decayed wood | Science Advances
https://advances.sciencemag.org/content/7/11/eabd9138

Wooden floors rotted by fungi generate electricity when walked on | New Scientist
https://www.newscientist.com/article/2270527-wooden-floors-rotted-by-fungi-generate-electricity-when-walked-on/

The cell wall of wood is mainly composed of cellulose , hemicellulose , and lignin . Furthermore, cellulose is composed of an amorphous region and a crystal region, and when pressure is applied to the crystal, the charges of the atoms that make up the crystal are biased and charges appear on the surface of the crystal. This phenomenon is called the piezoelectric effect, and it is known that this effect is exhibited not only with wood but also with chitin and bone. Although it has been known for decades that pressure can be applied to wood to generate electricity by the piezoelectric effect, the rigidity of the wood itself is high and the power generation efficiency is poor, so power generation using wood as it is is considered to be inefficient. I have come.

Therefore, Jianguo et al. Expected that the power generation effect could be enhanced by rotting the wood and reducing the rigidity of the wood, and conducted an experiment to confirm the piezoelectric effect with the rotten wood.

As a result of Jianguo et al. Rotting balsa wood with white-rot fungi , lignin and hemicellulose in the wood collapsed rapidly, reducing weight by almost half, reducing rigidity and improving compressibility. When the piezoelectric effect was generated in this state, a voltage of 0.87 volts and a current of 13.3 nanoamperes were obtained from wood of 15 mm x 15 mm x 13.2 mm. This is 55 times more powerful than it was before the wood was rotten, Jianguo and colleagues say.

Jianguo and colleagues hope that this technology will be useful in developing new technologies such as floors that detect when an elderly person has fallen and send a signal. He said he was discussing with. 'Opening up the possibilities of new building design technologies that generate electricity through a variety of human activities,' the research team said in a treatise.