Papers by Author: Takashi Ida

Abstract: To investigate the effect of oxygen pressure on the synthesis of LiNiO2 cathode material for Li secondary battery, powder was prepared by emulsion method and calcined at 750°C for 24 h under various oxygen gas pressures. LiNiO2 single phase could be synthesized under oxygen pressure of 101.3~103.3 kPa but not under air atmosphere. Cation mixing in Li site of LiNiO2 lowered as oxygen pressure increased and was saturated around 103.3 kPa. The lowest cation mixing, 7.0% of Ni3+ in the Li site was obtained at 750°C for 24 h under 103.3 kPa of oxygen pressure.

Abstract: A quantitative basis for rocking curve measurements of preferentially oriented polycrystalline thin films is presented. The Gaussian function is used for modeling the preferred orientation of crystallites around the plane normal of the specimen surface. A theoretical rocking curve is fitted to the observed curve by the least-squares method, and the degree of preferred orientation, given in volume fraction, can be derived from a refined preferred orientation parameter of the distribution function even when the preferred orientation is very small. Uses of diffractometers equipped with parallel-beam optics and the integrated intensity rather than peak intensity are important for reliable rocking curve measurement.