(301a) Controllable Hydrothermal Conversion from Ni-Co-Mn Carbonate Nanoparticles to Spheres

Abstract: Starting from Ni-Co-Mn carbonate nanoparticles prepared by microreaction technology, uniform spherical particles of Ni_1/3Co_1/3Mn_1/3CO₃ with size of 3-4 μm were obtained by a controllable hydrothermal conversion with the addition of (NH₄)₂CO₃. Based on characterizations on evolution of morphology and composition with hydrothermal treatment time, we clarified the mechanism of this novel method as a dissolution-recrystallization process as well as the effects of (NH₄)₂CO₃ concentration on the morphology and composition of particles. By changing concentrations and ratio of staring materials for nano-precipitation preparation, we achieved monotonic regulation on the size of the spherical particles, and the synthesis of Ni_0.4Co_0.2Mn_0.4CO₃ and Ni_0.5Co_0.2Mn_0.3CO₃, respectively. In addition, the spherical particles with core-shell structure were preliminarily verified to be available by introducing nano-precipitates with different compositions in the hydrothermal treatment in sequence.