Preparation of battery-grade lithium carbonate by microbubble enhanced CO2 gas–liquid reactive crystallization

Abstract

Lithium carbonate (Li₂CO₃), as one of the most important basic lithium salts, has a high demand in the lithium ion battery industry, including the preparation of cathode materials, lithium metal, and electrolyte additives. However, the traditional preparation process of Li₂CO₃ is hampered by the introduction of Na⁺ metal impurity, and the particle size is too large to meet the requirements of battery-grade products. Here, we propose a gas–liquid reactive crystallization process for the one-step preparation of battery-grade Li₂CO₃ using CO₂ instead of Na₂CO₃ as the precipitant. This strategy avoids the introduction of Na⁺ metal impurity and can also capture and convert CO₂. Meanwhile, microbubbles were introduced into the system to enhance the mass transfer and regulate the crystallization process to efficiently prepare Li₂CO₃ products with the particle size meeting the requirements of the battery level. The kinetic parameters and crystallization mechanism of battery-grade Li₂CO₃ prepared by gas–liquid reactive crystallization were quantitatively analyzed through in situ tests and calculations. The feasibility of using the prepared battery-grade Li₂CO₃ as a raw material to synthesize an LiFePO₄ cathode for lithium ion batteries was verified. The strategy provides a new route for the controllable preparation of battery-grade Li₂CO₃ and the conversion of CO₂.