Preparation of Li2CO3 powder nanoparticles by vacuum freeze drying.

Decreasing the particle size of Li 2 CO 3 powder is beneficial for advancing its applications in the manufacturing of different materials and drug delivery. Therefore, in this study, a novel bottom-up process based on freezing is proposed for the production of nanoparticles. Herein, two methods of explosive nucleation were used: addition of an anti-solvent and rapid freezing. Explosive nucleation of Li 2 CO 3 occurred during the initial stage of anti-solvent addition; in contrast, in the freezing method, it occurred at a stage when the solute, which had not migrated, was extruded to the solid–liquid interface. Li 2 CO 3 concentration had an effect on both the crystal grain and particle size. The controlled preparation of Li 2 CO 3 nanoparticles was achieved within a certain range of A/B ratio; when the ratio decreased from 10/0 to 10/20 v/v, the controlled synthesis of Li 2 CO 3 nanoparticles was achieved. A lower concentration of Li 2 CO 3 decreased the size of the crystal grain and increased the size of the particles, as observed via transmission electron microscopy and dynamic light scattering. When the A/B ratio (where A is saturated Li 2 CO 3 solution and B is deionised water) was decreased below 10/20 v/v, the crystal grain size of Li 2 CO 3 did not reduce significantly. To further understand the nucleation, freezing was carried out at two temperatures, i.e. 223 ± 2 K and 267 ± 2 K. The lower freezing temperature resulted in a smaller crystal grain size and more concentrated distribution. [ABSTRACT FROM AUTHOR]