Papers by Keyword: Intergrowth Structure

Abstract: Cathode materials Li-[MnxNi1/2-x/2Co1/2-x/2]-O (x=0.333, 0.4, 0.6, 0.8, 0.9) were fabricated by lithium salts (LiNO3) and manganese-nickel-cobalt hydroxide precursors using the required amounts of Mn, Ni, Co for a given value of x. When Mn content is between 0.5 and 0.8, layered and spinel structure co-existed. Meanwhile the rate Li/M is also a key factor for synthesis of layered-spinel intergrowth structure cathode materials without other impurities. Li-[Ni0.2Co0.2Mn0.6]-O and Li-[Ni0.1Co0.1Mn0.8]-O were synthesized by a Two-step Co-precipitation method.

Abstract: Intergrowth-structured Bi4Ti3O12-BaBi4Ti4O15 (BiT-BBTi) single crystals were grown by a self-flux method, and the crystal structure and polarization properties were investigated. Transmission electron microscope observations and X-ray diffraction analysis presented direct evidence of the intergrowth structure composed of the alternate stacking of BiT and BBTi layers. The BiT-BBTi crystals showed a giant spontaneous polarization (Ps) along the a axis of 52 μC/cm2, which was larger than those of the crystals of BiT (46 μC/cm2) and BBTi (16 μC/cm2). The large Ps of the BiT-BBTi crystals is suggested to originate from the ferroelectric displacements of the Bi of Bi2O2 layers as well as from the Bi substitution for Ba induced by compositional deviation. It was found that the polarization properties of the BiT-BBTi crystals depend strongly on the composition.