DFT modeling of NMR contact shift mechanism in the ideal LiNi2O4 spinel and application to thermally treated layered Li0.5NiO2
Language
en
Article de revue
This item was published in
Chemistry of Materials. 2007, vol. 19, n° 17, p. 4166-4173
American Chemical Society
English Abstract
LiNi2O4 spinel-type phases were prepared by thermal treatment of electrochemically deintercalated layered Li~0.5NiO2. The phase transformation was followed by 7Li NMR, showing a gradual change of the signal from the layered ...Read more >
LiNi2O4 spinel-type phases were prepared by thermal treatment of electrochemically deintercalated layered Li~0.5NiO2. The phase transformation was followed by 7Li NMR, showing a gradual change of the signal from the layered compound. The characteristic signal of the latter (related to local Li/vacancy and Ni3+/Ni4+ ordering) vanishes after heating to 150 C and is replaced by a new signal showing faster exchange kinetics (originating from Ni3+/Ni4+ hopping around Li), which progressively transforms into a broad distribution of signals. Around 200 C, a set of three positively shifted signals is observed, corresponding to the appearance of the spinel phase as seen from XRD; these signals disappear after heating to 240 C, corresponding to the beginning of decomposition of the spinel into a disordered Rm type phase with oxygen evolution as previously shown by Guilmard et al. (Chem. Mater. 2003, 15, 4476 and 4484)...Read less <
English Keywords
DFT
Spinel
Inorganic coumpounds
Layered compounds
Contact shift mechanism
LiNiO4
Origin
Hal imported