Nucleation of Battery-Grade Li₂CO₃ Driven by Nanobubbles for Spent Battery Recycling

Solvent-based battery recycling plays a pivotal role in mitigating metal demand pressures and advancing the circular economy. While numerous recycling strategies focus on enhancing the leaching efficiency of critical metals, the purification and refinement of leached lithium ions remain significant challenges. To address this bottleneck, we propose a strategy integrating element separation and nucleation control to remove impurities from lithium-enriched solutions and precipitate lithium ions. This approach employs a lanthanum-based adsorbent for purification and ultrafine nanobubbles for the preparation of battery-grade Li₂CO₃ (BG-Li₂CO₃). The process ensures complete removal of all impurity elements from the lithium-enriched solution, with the impurity-removing agents being recyclable. The synthesized LiFePO₄ (LFP) exhibits a higher mean voltage (3.42 V vs Li/Li⁺) and energy density (527 Wh kg-¹) compared to commercial LFP counterparts. Techno-economic-environmental analysis demonstrates that the ultrafine nanobubble nucleation strategy significantly streamlines the purification and refinement process, offering a sustainable method for lithium extraction from salt lakes, ores, and spent lithium batteries, while also enabling efficient CO₂ utilization across these applications.