“To my knowledge, there has never been any similar work reported,” explained Dr. Kang Xu of the Army Research Laboratory, a researcher only peripherally related to the study. “It could lead to revolutionary progress in area of solid state batteries.”
Most batteries have at either end a layer of material for the electrodes which can help move ions through the electrolyte. Chunsheng Wang, a professor in the University of Maryland’s Department of Chemical and Biomolecular Engineering, and his team have made a single material that incorporates the properties of both the electrodes and electrolyte.
“Our battery is 600 microns thick, about the size of a dime, whereas conventional solid state batteries are thin films - forty times thinner. This means that more energy can be stored in our battery,” said Fudong Han, the first author of the paper and a graduate student in Wang’s group.
The new material consists of a mix of sulfur, germanium, phosphorus and lithium. The compound is used as the ion-moving electrolyte. At each end, the scientists added carbon to this electrolyte to form electrodes that push the ions back and forth through the electrolyte as the battery charges and discharges. Like a little bit more sugar added at each end of a cookie-cream mixture, the carbon merely helps draw the electricity from side to side through the material.