Flooring made from chemically treated wood pulp could convert footsteps into usable electricity, according to University of Wisconsin–Madison researchers.

Wood pulp, a common component of flooring, is made partly from cellulose nanofibers. After the fibers are chemically treated, they produce an electrical charge when they come into contact with untreated nanofibers, which can be harnessed to power lights or charge batteries.Associate Professor Xudong Wang holds a prototype of his energy-harvesting technology. Image credit Stephanie Precourt.Associate Professor Xudong Wang holds a prototype of his energy-harvesting technology. Image credit Stephanie Precourt. Research led by Xudong Wang, associate professor of materials science and engineering, centers on the use of a technology called a triboelectric nanogenerator (TENG). The energy-harvesting device converts mechanical energy—in this case, vibrations from walking—into electricity.

Treated cellulose nanofibers incorporated into flooring provide a low-cost and effective way to harness this mechanical energy source, Wang says. Each functional portion inside such flooring would be only one millimeter thick or less and comprise two differently charged materials.

“Once we put these two materials together, electrons move from one to another based on their different electron affinity,” he says.

The electron transfer creates a charge imbalance that naturally wants to right itself. But as the electrons return, they pass through an external circuit. That process creates the harvestable energy.

“Our initial test in our lab shows that it works for millions of cycles without any problem,” Wang says. “We haven’t converted those numbers into years of life for a floor yet. But I think with appropriate design it can definitely outlast the floor itself.”

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