Selective Recovery of Critical Metals from Spent Lithium-ion Batteries Using Green Deep Eutectic Solvents

Abstract

This thesis advances cleaner routes for recovering critical metals from end-of-life lithium-ion batteries. I formulate low-toxicity deep eutectic solvents, green, inexpensive liquids, that selectively precipitate cobalt, nickel, and manganese at high purity. By precisely controlling supersaturation of the leach solutions, the metals crystallise as discrete solids without harsh acids, added reductants, or multiple purification steps. The approach reduces reagent use, energy demand, and waste while yielding high-value products suitable for reuse in new batteries. Comparative studies show how solvent composition governs selectivity by tuning hydrogen-bond donors/acceptors and water content. The work supports Australia’s circular economy goals and strengthens supply security for energy storage.