Researchers have developed a way to use wood to generate electricity via a chemical process that removes lignin from wood cells The piezoelectric effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. One of the materials that exhibit this effect is wood, and now researchers at the Swiss Federal Laboratories for Materials Science and Technology and ETH Zurich have developed a way to turn wood into a microgenerator.
The researchers used a chemical process to remove the lignin from the wood cells – the lignin is the substance that gives wood its rigidity. Once the lignin is removed, the result is a sort of wood sponge, made up of thin layers of cellulose that can be easily squeezed together, and then expand back to their original form.
The test cube was then repeatedly compressed, resulting in a voltage of around 0.63V – enough to power a sensor. By using around 30 of the wood nano-generators in parallel, and compressing them with a force equal to the bodyweight of an adult, researchers were able to generate enough electricity to light up a simple LED display. This holds out the possibility that wooden flooring could be used to convert the energy of people walking to electricity. Going one step further towards sustainability, the researchers also developed a way to remove the lignin from wood without using harsh chemicals – by using a fungus, Ganoderma applanatum, which breaks down lignin naturally. Empa researcher Javier Ribera explains: “The fungus breaks down lignin and hemicellulose in the wood particularly gently.” He adds that the process can be easily controlled in the lab. This is not the first time that we here at Springwise have covered an exciting development in piezoelectricity. Previous innovations in this space have included the use of piezoelectric pavement tiles to generate electricity from walking pedestrians, and a piezoelectric fabric that can generate electricity as it moves. Written By: Lisa Magloff Website: empa.ch Contact: empa.ch/web/empa/contact arunbhatiaconsulting.com