By Cameron Chai
In a development that is deemed to be the solution for cheaper and long-lasting solid oxide fuel cells, researchers from Oak Ridge National Laboratory (ORNL) of the United States Department of Energy have devised a microscopy method to locate the position of missing oxygen atoms.
Fuel cells operate on the basis of a chemical reaction between a fuel and oxygen to generate electricity. The efficiency of fuel cells is determined by the arrangement, structure and distribution of vacancies in which oxygen atoms used to exist as conducting oxygen ions pass through these vacancies as they traverse the fuel cell.
Fuel cells are considered to be efficient instruments of energy conversion in spite of their low lifespan and high costs associated with them. In order to realize their full potential, it is imperative to understand the role, behavior and nature of interaction of the oxygen vacancies in the fuel cell.
Scientists at ORNL employed scanning transmission electron microscopy to identify the vacancy distribution in the cathode of a fuel cell. Though the vacancy does not produce any signal of its own on the electron micrograph, it could be identified by the lattice expansion caused in places where vacancies were present.
The experiment results were validated using theoretical models. This technique will facilitate the development of improved fuel cells in a systematic manner as opposed to random trial and error methods.
The study’s results are reinforced by another similar study, which demonstrates the method to acquire parameters from electron microscopy data corresponding to vacancy-ordered systems.