Membrane-based extraction of critical materials from spent batteries and other mineral wastes

The growing demand for critical materials such as lithium, nickel, cobalt, and manganese in electric vehicles, renewable energy systems, and advanced electronics has intensified the need for sustainable recovery strategies. Spent lithium-ion batteries, mineral tailings, and industrial by-products represent valuable secondary resources that can support circular economy objectives. However, conventional hydrometallurgical and pyrometallurgical processes are energy-intensive, chemically demanding, and often generate significant secondary waste, including sludge and saline effluents. Membrane-based separation technologies have emerged as promising alternatives due to their modular design, lower energy requirements, and potential for selective metal recovery. Pressure-driven processes, including ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO), as well as electro-driven systems such as electrodialysis (ED), enable target separations (e.g., Li/Mg, Co/Ni, Li/Co-Ni-Mn) through size exclusion, charge-based selectivity, and ion-membrane interactions. Nevertheless, membrane performance in realistic leachates characterized by low pH, high ionic strength, oxidants, and complex metal speciation is strongly governed by chemistry-driven failure modes. These include inorganic scaling (e.g., gypsum and silica), metal hydroxide precipitation, colloidal and organic fouling, redox-induced instability, and polymer degradation, which collectively contribute to flux decline, selectivity loss, and reduced membrane lifetime. This review critically evaluates membrane applications for battery and mineral waste valorization, linking dominant failure mechanisms to solution chemistry and long-term stability. Techno-economic considerations are discussed using normalized metrics (kWh/m 3 , kWh/kg metal, $/kg product), highlighting conditions under which membranes can become cost-competitive with conventional extraction routes.