Published by the Students of Johns Hopkins since 1896
September 24, 2020

Static electricity may soon help power your iPhone

By WILL EDMONDS | February 7, 2019

Though many of us experience it every day, static electricity remains somewhat poorly understood. Researchers have recently begun to look into the details behind how electricity is generated through frictional contact; that is, the molecular physics behind your hair’s propensity to stick to balloons. The research being conducted at the University of Buffalo and Kansas State University has so far uncovered some interesting twists to the electron exchange known as triboelectrification that takes place between two materials in contact with one another.

Static electricity generated by interacting conductive materials is rather simple to understand. 

When two conductive materials come into contact with one another, there is a net charge imbalance between the two which is then resolved through the electrochemical transfer of electrons. Repeated contact of these materials greatly increases the magnitude of such an effect.

The questions which remain are regarding those characteristics that relate to dielectric materials rather than conducting materials. Dielectric materials are poor conductors, so applying the traditional electron exchange theory seems challenging at best. 

James Chen, an assistant professor at the University of Buffalo, expanded on the promise of his team’s research. 

“The idea our study presents directly answers this ancient mystery, and it has the potential to unify the existing theory,” Chen said in a press release.

There are several possible applications to this technology. Triboelectric nanogenerators (or TENGs) are devices that can be used to harvest energy from everyday physical actions. Chen and his fellow researcher, Zayd Leseman, are working to engineer triboelectric nanogenerators. Once these devices are built and perfected, there is practically limitless potential. 

Chen described his view on the future of TENGs in the same press release. 

“The friction between your fingers and your smartphone screen. The friction between your wrist and smartwatch. Even the friction between your shoe and the ground. These are great potential sources of energy that we can to tap into,” he said.

In order to determine how dielectric materials interact analogously to conductors without the latter’s conductive properties, Chen and Leseman simulated material contact between several dielectric surfaces.

The results pointed to the surface dipoles as the culprit. 

“[There was a relation between] the formation of the surface dipoles [and] the deformations of the surface lattices. The surface dipoles are theorized to be one cause for the triboelectric effect,” the study reads. 

Physical deformations caused by interacting materials also changed the distribution of electrical charges. 

The challenge with TENGs is largely that static electricity does not produce huge amounts of electricity — and current technology does not allow for efficient collection of the electric potential that is produced. While this may prevent your typical doorknob shock from harming anyone, it is not as good if the goal is to provide significant power to a smartphone or light bulb. 

Still, the technological promise is there: Since the first TENG device was produced in 2012, scientists have achieved a conversion efficiency of 72 percent. 

Correction: The original article incorrectly identified one of the students quoted as Sylvana Schaffer. This quote has since been removed. The News-Letter regrets this error.

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