Scientists at the United States Department of Energy’s Oak Ridge National Laboratory are using a novel microscopy method to probe the reactions that limit the widespread deployment of fuel cell technologies. The technique, called electrochemical strain microscopy, enables the team to examine the dynamics of oxygen reduction/evolution reactions in fuel cell materials. It could reveal ways to redesign or cut the costs of the energy devices. Amit Kumar, a research scientist at ORNL’s Center for Nanophase Materials Sciences, and co-author of a paper describing the team’s findings in the journal Nature Chemistry, said, “If we can find a way to understand the operation of the fuel cell on the basic elementary level and determine what will make it work in the most optimum fashion, it would create an entirely new window of opportunity for the development of better materials and devices.” Fuel cells are highly efficient at converting chemical energy into electrical energy, but their commercial potential has been constrained by their high cost – due, in large part, to the use of platinum as a catalyst. Understanding the oxygen-reduction reaction, which controls the efficiency and longevity of the cell, has heretofore not been probed because existing device-level electrochemical techniques were not suited to study the reaction at the nanoscale. According to ORNL’s Stephen Jesse, builder of the ESM microscope, “If the reaction is controlled by microstructure features that are much finer than a micron, let’s say grain boundaries or single extended defects that are affecting the reaction, then you will never be able to catch what is giving rise to reduced or enhanced functionality of the fuel cell. You would like to do this probing on a scale where you can identify each of these defects and correlate the functionality of the cell with these defects.”
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