Toward\na Circular Lithium Economy with Electrodialysis:\nUpcycling Spent Battery Leachates with Selective and Bipolar Ion-Exchange\nMembranes

Recycling spent lithium-ion\nbatteries offers a sustainable solution\nto reduce ecological degradation from mining and mitigate raw material\nshortages and price volatility. This study investigates using electrodialysis\nwith selective and bipolar ion-exchange membranes to establish a circular\neconomy for lithium-ion batteries. An experimental data set of over\n1700 ion concentration measurements across five current densities,\ntwo solution compositions, and three pH levels supports the techno-economic\nanalysis. Selective electrodialysis (SED) isolates lithium ions from\nbattery leachates, yielding a 99% Li-pure retentate with 68.8% lithium\nretention, achieving relative ionic fluxes up to 2.41 for Li<sup>+</sup> over transition metal cations and a selectivity of 5.64 over monovalent\ncations. Bipolar membrane electrodialysis (BMED) converts LiCl into\nhigh-purity LiOH and HCl, essential for battery remanufacturing and\nreducing acid consumption via acid recycling. High current densities\nreduce ion leakage, achieving lithium leakage as low as 0.03%, though\nhydronium and hydroxide leakage in BMED remains high at 11–20%.\nOur analysis projects LiOH production costs between USD 1.1 and 3.6\nper kilogram, significantly lower than current prices. Optimal SED\nand BMED conditions are identified, emphasizing the need to control\nproton transport in BMED and improve cobalt–lithium separation\nin SED to enhance cost efficiency.