New power cell is both a generator and a battery

Imagine being far from the comforts of home — maybe hiking through a remote wilderness or patrolling a war zone — but still certain you can keep your cellphone charged … simply by walking.

That could soon be possible, thanks to a new kind of power cell developed by researchers at the Georgia Institute of Technology. The cell works by converting mechanical energy — say, the force produced with every footstep as your shoe heel hits the ground — directly into chemical energy that can later be used, battery-style, to produce electricity.

Georgia Tech engineers say the self-charging power cell can harness mechanical energy far more efficiently than do systems that rely on a combination of generators and batteries to convert mechanical energy first into electrical energy and then into stored chemical energy.

“People are accustomed to considering electrical generation and storage as two separate operations done in two separate units,” said Georgia Tech professor Zhong Lin Wang. “We have put them together in a single hybrid unit to create a self-charging power cell, demonstrating a new technique for charge conversion and storage in one integrated unit.”

By essentially combining a generator and battery in one device, the new power cell could reduce the amount of weight and space now needed to accommodate separate devices for producing, storing and delivering energy on the go.