Supervising the research at Hopkins were materials science and engineering professors Theodore O. Poehler and Peter C. Searson. Along with researchers Jeffrey Killian, Hari Sarker and Jossef Gofer, they have produced polymers that can generate up to 2.5 volts in cells that potentially could compete with the 3-volt lithium batteries now on the market. As part of this collaborative effort, engineers at Hopkins' Applied Physics Laboratory, led by Joseph Suter, have been paving the way for practical systems applications by linking the batteries with an innovative solar cell charging system. They also have contributed important technology and fabrication know-how to the project. Building an all-plastic cell was difficult because most polymers that conduct electricity lack sufficient energy difference to serve as electrodes.
Polymers are very large molecules consisting of long, interconnected chains of smaller molecules.
These macromolecules are the basis for many important materials, including plastics, synthetic fibers and coatings. Although other researchers have used a polymer for one of these components, Hopkins scientists are among the first to create a practical battery in which both of the electrodes and the electrolyte are made of polymers. Lab tests indicate that the Hopkins cells can be recharged and reused hundreds of times without degradation. The polymer batteries also contain no liquids, which can leak and pose safety hazards. The all-plastic battery operates efficiently in extreme heat or cold.