UW–Madison materials engineers find new way to convert footsteps into electricity

University of Wisconsin–Madison materials engineers have developed a new method that enables conversion of footsteps into usable electricity.

Xudong Wang, an associate professor of materials science and engineering at UW–Madison, his graduate student Chunhua Yao, and their collaborators developed a method that uses wood pulp, a common component of flooring, to generate green energy.

The pulp is partly made of cellulose nanofibers, which are capable of generating electricity.

The chemically treated tiny fibers produce an electrical charge when they come into contact with untreated nanofibers.

When embedded within flooring, the nanofibers will be able to produce electricity that can be harnessed to power lights or charge batteries.

Wang said: “Because wood pulp is cheap, abundant and renewable, flooring that incorporates the new technology could be as affordable as conventional materials.”

Though there are similar materials currently available to harness footstep energy, they are expensive, nonrecyclable, and impractical at a large scale.

Wang, whose research focuses on using vibration to generate electricity, said that chemically treated cellulose nanofibers are a simple, low-cost and effective alternative for harnessing this broadly existing mechanical energy source.

The UW–Madison team’s new method is the latest in a green energy research field called “roadside energy harvesting” that could rival solar power.

Wang said: “Roadside energy harvesting requires thinking about the places where there is abundant energy we could be harvesting.

“We’ve been working a lot on harvesting energy from human activities. One way is to build something to put on people, and another way is to build something that has constant access to people. The ground is the most-used place.”

Heavy traffic floors in hallways and places like stadiums and malls that incorporate the new technology could have potential to generate significant amounts of energy.

Image: Associate Professor Xudong Wang holds a prototype of the researchers’ energy harvesting technology, which uses wood pulp and harnesses nanofibers. Photo courtesy of Stephanie Precourt/University of Wisconsin–Madison.