%0 Journal Article
%A Ceretti, Monica
%A Wahyudi, Olivia
%A André, Gilles
%A Meven, Martin
%A Villesuzanne, Antoine
%A Paulus, Werner
%T (Nd/Pr) 2 NiO 4+δ : Reaction Intermediates and Redox Behavior Explored by in Situ Neutron Powder Diffraction during Electrochemical Oxygen Intercalation
%J Inorganic chemistry
%V 57
%N 8
%@ 1520-510X
%C Washington, DC
%I American Chemical Society
%M FZJ-2019-00342
%P 4657 - 4666
%D 2018
%X Oxygen intercalation/deintercalation in Pr2NiO4+δ and Nd2NiO4+δ was followed by in situ by neutron powder diffraction during the electrochemical oxidation/reduction reaction, in a dedicated reaction cell at room temperature. Three phases were identified for both systems: orthorhombic RE2NiO4.23, obtained by classical solid-state reaction, gets reduced in a 2-phase reaction step to a tetragonal intermediate phase RE2NiO4+δ with 0.07 ≤ δ ≤ 0.10, which again transforms on further reduction in a 2-phase reaction step towards the stoichiometric RE2NiO4.0. Electrochemical oxidation does not proceed fully reversibly for both cases: while the re-oxidation of Nd2NiO4+δ is limited to the tetragonal intermediate phase with δ = 0.10, the homologous Pr2NiO4+δ can be re-oxidized up to δ = 0.17, showing orthorhombic symmetry. For the tetragonal Pr2NiO4.12 phase, we were able to establish a complex anharmonic displacement behavior as analyzed by single crystal neutron diffraction and Maximum Entropy Analysis, in agreement with a low-T diffusion pathway for oxygen ions activated by lattice dynamics.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:29620364
%U <Go to ISI:>//WOS:000430437400050
%R 10.1021/acs.inorgchem.8b00393
%U https://juser.fz-juelich.de/record/859489