Constructing High-Selective Cation Exchange Membrane via Embedding Sulfonated Lithium-Ion Sieve for Enhanced Lithium Recycling from Spent Batteries Effluents

Abstract

Recycling of lithium resources from spent battery effluents is critical for their valorization and the amelioration of their adverse environmental effects. Selectrodialysis (SED) based on monovalent-selective electrotransport offers a promising approach for lithium recovery from these streams. However, the separation efficiency is limited by the weak selectivity and stability of monovalent selective cation exchange membranes (MSCEMs) in acidic media. In this study, a highly selective MSCEM is developed by embedding sulfonated hydrogen manganese oxide (HMO) into polyvinylidene fluoride (PVDF) to construct inner Li-ion transport channels. Meanwhile, adjacent oxide groups on the sulfonated HMO surface serve as hopping-sites for fast lithium-ion transport during SED, contributing to a lithium-ion flux of 1.10–2.61 mol m⁻² h⁻¹. Compared with commercial MSCEMs, the membrane developed in this work exhibits a 36-fold increase in the selectivity for lithium separation from co-existing cations (e.g., Co²⁺ and Ni²⁺) and exhibited good stability over 130 h of operation in acidic mixtures. Overall, this study provides a new avenue for the development of Li-selective MSCEM with acid resistance, thereby enhancing the SED-based membrane process for the reclamation of Li resources from spent battery effluents.