Probing Short-Range Order in Disordered Crystalline Materials for Extreme Environments.

International audienceStructurally disordered oxide materials are used in a variety of energy technologies from solid oxide fuel cells to nuclear fuels and waste forms. Here we present selected examples of synergistic experimental and modeling approaches that reveal the short-range order in oxide materials that appear disordered over longer length scales. The key to our research strategy is state-of-the-art neutron total scattering experiments at the world’s most intense pulsed neutron beam, the Spallation Neutron Source (ONRL); neutrons scatter intensely from oxygen permitting analysis of anion sublattice behavior and total scattering yields pair distribution function (short-range) data. In one case, total scattering experiments with combined first principles and Reverse Monte Carlo modeling revealed the short-range oxygen clustering in the nuclear fuel UO2+x. In another, Pauling’s rules were used to predict short-range ordering in AB2O4 spinel and A2B2O7 pyrochlore oxides, proposed for use in lithium battery applications, actinide transmutation matrices, and nuclear waste forms