Most power systems use separate generators and batteries, but researchers at the Georgia Institute of Technology have created a hybrid energy device that converts and stores energy in a single cell. Rather than converting mechanical energy to electrical energy, the power cell converts it to chemical energy that is stored until released as electricity. The process makes it more efficient to use mechanical energy.

The power cell uses a piezoelectric membrane, a material that can capture energy from movement. When the membrane is moved, it drives lithium ions across the cell, and those ions are then stored as chemical energy.

The cell can be used in a number of ways, such as being placed in the heel of a shoe to capture energy and power small electronics. Funded in part by DARPA and the U.S. Air Force, the cells may one day be used by soldiers. They could also be used in pavement to capture energy from tires, to capture wave energy in the ocean, or for any other type of mechanical energy harvesting.

The researchers have built and tested more than 500 cells so far. They estimate the power cell may be five times more efficient than normal cells with separate generation and storage. Their next step will be improving the case for the cell, which will make it more efficient.

Main photo credit: Gary Meek/Georgia Institute of Technology