Mineral scaling, driven by concentration polarization, is an inevitable challenge in electro-membrane technologies for recovering valuable metals from lithium-ion battery (LIB) leachates. Here, we elucidate the synergistic scaling mechanism and propose an electric field-assisted organic acid control (eF-OAC) principle to prevent membrane mineral scaling while enabling metal recovery. The eF-OAC utilizes an electric field to direct organic acids into the membrane matrix, where ligand-metal coordination dissolves hydroxide-rich scale and mobilizes metal species for selective transport and crystallization. Dynamic experimental analysis reveals that concentration polarization enriches metal hydroxides at the membrane interfaces and pores. Static density functional theory calculations further demonstrate that organic ligands are thermodynamically favored over sulfonate groups for coordinating metal hydroxides, enabling targeted dissolution from the membrane. Leveraging this molecular-level selectivity, the eF-OAC converts scale into recoverable crystalline products. In optimized electro-membrane crystallization, this eF-OAC achieves high recovery rates of 97.6% for Li+, 95.3% for Ni2+, 94.2% for Co2+, and 97.8% for Mn2+. It further yields high-purity Li2SO4 (99.4%), Ni(OH)2 (99.2%), Co(OH)2 (99.0%), and Mn3O4 (99.3%). This study clarifies the mechanisms of mineral scaling and demonstrates a scaling-free approach that transforms fouling liabilities into valuable resource recovery for spent LIBs. It is challenging to extract lithium from lithium-ion battery leachates due to mineral scaling. Here the authors report a field assisted organic acid control method to optimize lithium extraction from ionic mixtures.
Qiu et al. (Tue,) studied this question.