Nano-generators from ordinary wood will turn the floor into…

Swiss researchers from ETH Zurich and EMPA have created a new material with piezoelectric properties that can generate electricity when walked on. The idea, of course, is not new - they have tried to use the energy of human steps for the passive generation of electricity many times and not without success. The material itself and the method of obtaining it are of interest - this is ordinary wood treated with a special fungus.

To maximize the use of the piezoelectric potential, the material must be pliable, but elastic, so that it not only easily deforms, but also quickly returns to its original state without damage. Wood is prevented from making fibers of lignin, a kind of natural polymer, which gives this material strength. Swiss scientists have developed two new "delignification" methods that safely remove lignin, turning wood into a soft, porous sponge.

In the first case, a chemical method is used, soaking in a solution of hydrogen peroxide and acetic acid. A cube of material obtained by this method with face sizes of 1.5 cm withstood more than 600 compression cycles and gave out a voltage of 0.63 V. An array of 30 cubes, under the weight of an adult, was able to power a small LCD display.

In the second case, biological treatment was applied, removing lignin from wood using the fungus Ganoderma applanatum, which decomposes it safely. It turned out to be cheaper, cleaner and more profitable, the voltage on the cube increased to 0.87 V. It is still too small for lighting or connecting household appliances, but it already looks quite promising as a source of energy for smart home sensors.