Tribo-electric effect is an effect of electricity generation, when two dissimilar materials come into contact and electrons migrate from one to another. Most of us have observed the tribo-electric effect in their life when rubbed a balloon at the birthday party against someone’s hair. The effect was the base for the development of the breakthrough triboelectric generator device in 2012 by the researchers of Georgia Institute of Technology. Today more than 60 research groups in the World work on the development and application of the triboelectric generators in various industries including wearable electronics, offshore energy harvesting, medicine, implantable sensors and others.
Recently, researchers from University of Wisconsin-Madison and Forest Product Laboratories in USA developed a triboelectric nanogenerator (TENG) to embed into flooring to convert footsteps into electricity. They proposed to use cellulose nanofibrils films in TENG, since this is an abundant material, bio-friendly, flexible and transparent. On top of it, cellulose exhibits a high tendency to loose electrons, which is the basic requirement for the development of an efficient TENG. It was combined with triboelectrically negative material – fluorinated ethylene propylene (FEP).
The generator was assembled by separating thin CNF and FEP films by a spacer and connecting them to external circuit through copper tapes. When the external force is applied, as in the case if someone steps onto TENG embedded flooring, the FEP and CNF films come into contact with latter loosing electrons. When the external force is relieved, the contact is released due to flexibility of the materials and current is generated to restore the balance of electrons.
As pointed out by the researchers, this technology can be used in hallways with high traffic, large stadiums and malls, where a large amount of energy can be produced.
Further details can be found in the original article: Triboelectric nanogenerators and power-boards from cellulose nanofibrils and recycled materials Chunhua Yao, Alberto Hernandez, Yanhao Yu, Zhiyong Cai, Xudong Wang, http://dx.doi.org/10.1016/j.nanoen.2016.09.036.