Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 56: Materials for Energy Storage II (joint session KFM/CPP)
CPP 56.3: Vortrag
Mittwoch, 14. März 2018, 15:50–16:10, EMH 025
Structural and microstructural evolution during oxygen intercalation in Pr2NiO4.25 single crystal investigated by in-situ synchrotron diffraction — •Avishek Maity1,2, Rajesh Dutta3, Monica Ceretti3, Dmitry Chernyshov4, and Werner Paulus3 — 1Institut für Physikalische Chemie, Georg-August Universität Göttingen, 37077 Göttingen, Germany — 2Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), 85748 Garching, Germany — 3Institut Charles Gerhardt, Université de Montpellier, 34095 Montpellier, France — 4The European Synchrotron-ESRF, 38000 Grenoble, France
Pr2NiO4+x is a promising oxygen membrane material having excellent ionic conductivity at moderate T. Oxygen diffusion occurs through interstitial sites via phonon assisted diffusion mechanism. We found Pr2NiO4.25 to be structurally extremely complex, showing large oxygen (interstitial) and charge (Ni2+/Ni3+) ordered domains, and forming giant unit cells up to 6000000 Å3. In order to explore the oxygen diffusion from structural and microstructural aspect as a function of oxygen stoichiometry (0<x<0.25), we investigated in-situ electrochemical (EC) oxygen intercalation on a 50 micron highly twinned single crystal mounted in a specially designed EC cell using synchrotron diffraction at BM01A@ESRF. We have followed phase transitions (ortho → tetra → ortho) and evolution of domain structure with a very special focus on the presence or absence of grain boundaries. This in-situ study allowed during an EC reaction to explore whole reciprocal space i.e. microstructure, twin domains including diffuse scattering.