Selective electrodialysis with bipolar membranes for cobalt and lithium recovery from spent lithium-ion batteries

Abstract

The recovery of valuable metals from spent lithium-ion batteries is pivotal for overcoming lithium resource shortages and mitigating environmental pollution. Herein, we propose a novel selective electrodialysis with bipolar membranes (BMSED) process for simultaneous cobalt and lithium recovery from a citric acid-leaching lithium-ion battery solution. By taking advantage of the accelerated water dissociation of bipolar membranes and the monovalent selectivity of Li⁺ over Co²⁺ ions from selective electrodialysis, one-step preparation of 99.96% purity LiOH, cobalt salt, and 0.63 mol/L citric acid solution was achieved. The steric hindrance effect of citrate across anion-exchange membranes was investigated via positron annihilation lifetime spectroscopy characterization. The competitive migration between the proton and metal cations across the cation-exchange membrane could decrease the current efficiency. A carbon footprint analysis revealed that the BMSED procedure accounted for only 18.40% of the total carbon emissions, demonstrating the environmental friendliness of this recycling method.