On The LixNi0.70Fe0.15Co0.15O2 System: An X-Ray Diffraction and Mössbauer Study

• Published in: Journal of solid state chemistry Vol. 159; no. 1; pp. 103 - 112
• Main Authors: Prado, G., Fournès, L., Delmas, C.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-06-2001; Elsevier
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Inorganic compounds; intercalation; layered oxides; lithium transition metal oxides; lithium-ion batteries; Mössbauer spectroscopy; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Water, oxides, hydroxides, peroxides; lithium-ion batteries; intercalation; lithium transition metal oxides; layered oxides; Mössbauer spectroscopy; Nickel oxides; Moessbauer effect; Lithium oxides; Reverse reaction; Cobalt oxides; Intercalation compounds; XRD; Désinsertion; Experimental study; Ion distribution; Redox reactions; Solid solutions; Chemical composition; Iron oxides; Electrochemical reaction; Electrochemical cells; Crystal structure
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.2001.9137

The structural modifications and redox processes occurring during lithium deintercalation from the quasi-stoichiometric Li0.97(Ni0.70Fe0.15Co0.15)1.03O2 phase were studied by X-ray diffraction and Mössbauer spectroscopy. A solid solution is observed in the whole deintercalation domain (0.08≤x≤0.97); Rietveld refinement of the XRD pattern shows a strong decrease of the M–O bond distance upon lithium deintercalation. The Mössbauer study shows that nickel and iron ions are simultaneously oxidized, a large number of the iron ions being stabilized in the high-spin tetravalent state. Comparison with the data obtained in the Lix(Ni,Fe)O2 system emphasizes the effect of the small cobalt ions on the facility to oxidize iron ions.