Journal of the Electrochemical Society, Vol.143, No.4, 1168-1175, 1996
Optimization of the Composition of the Li-1-Zni1+zo2 Electrode Materials - Structural, Magnetic, and Electrochemical Studies
Lithium nickel oxide, used as the positive electrode in lithium batteries, crystallizes in the rhombohedral system ( m) with a layered structure. In fact, stoichiometric LiNiO2 has never been reported. The true formula is Li1-zNi1+zO2 (0.00 < z < 0.20); z is dependent on the experimental conditions. This nonstoichiometry leads to a strong decrease of the battery performance. Therefore, several methods of preparation were investigated to synthesize stoichiometric LiNiO2. The Li0.98Ni1.02O2 composition, which is very close to the ideal one, was obtained from a mixture of Li2O and NiO heated at 700 degrees C. This quasi-2D LiNiO2 was Submitted to several thermal treatments, in order to determine the influence of the temperature on the composition. Purposely lithium deficient phases were also prepared. Correlations between the composition of each material (deduced from the Rietveld refinement of the x-ray diffraction pattern) and the magnetic and electrochemical behavior are discussed.
Keywords:SECONDARY LITHIUM CELLS;LINIO2