Effect of Transition Metal Ions on the Reactive Crystallization and Morphology of Lithium Carbonate

Abstract

The increasing demand for lithium-ion batteries has intensified the importance of lithium carbonate, whose crystallization behavior, morphology, and filtration characteristics are influenced by crystallization conditions and transition-metal impurities, particularly Ni²⁺, Co²⁺, and Mn²⁺. In this study, the effects of these ions on the reactive crystallization of lithium carbonate were systematically investigated. Crystal morphology and phase composition were characterized using SEM, FESEM-EDS, XRD, and FTIR, while zeta potential measurements were performed to evaluate surface charge, and TGA was used to assess thermal decomposition behavior. The results showed that the presence of Co²⁺ promoted more compact, rounded crystals with smoother surfaces, whereas Ni²⁺ induced elongated, thin, plate-like structures with increased surface irregularity. Mn²⁺ resulted in intermediate shapes. Zeta potential measurements revealed a significant increase in surface charge in the presence of metal ions, enhancing electrostatic repulsion and reducing particle aggregation. Filtration behavior was also significantly influenced by crystal morphology: crystals formed in pure media exhibited the highest specific cake resistance, whereas Co²⁺ and Mn²⁺ substantially improved filterability by producing more permeable filter cakes, while Ni²⁺ showed a moderate effect. These findings highlight the critical role of transition-metal impurities in regulating lithium carbonate crystallization, crystal properties, and filtration performance.