Selective Interfacial Regulation of LiMn ₂ O ₄ for Flow Electrochemical Lithium Extraction

ABSTRACT

Gas‐produced water (GPW) is increasingly recognized as an important low‐quality aqueous lithium resource. Electrochemical lithium extraction using LiMn ₂ O ₄ (LMO) offers a promising strategy for lithium extraction from aqueous resources. However, its application to GPW is hindered by competing‐ion co‐intercalation and Mn dissolution, which compromise extraction selectivity and stability. Inspired by selective ion transport in biological ion pumps, a Li _0.33 La _0.56 TiO ₃ (LLTO)‐engineered LMO interface is developed to integrate Li ⁺ ‐sieving nanochannels with interfacial stabilization. Experimental and mechanistic analyses demonstrate that the LLTO‐engineered interface promotes local Li ⁺ enrichment, while its Li ⁺ ‐sieving nanochannels restrict competing‐cation access, thereby accelerating selective Li ⁺ transport and optimizing Li ⁺ storage. Concurrently, the LLTO suppresses Mn dissolution, thereby preserving interfacial stability during repeated Li ⁺ extraction and release. Furthermore, the cyclic flow 3LLTO‐LMO//3LLTO‐λ‐MnO ₂ system delivers 16.6 mg·g ⁻¹ lithium release capacity after 10 cycles and achieves an 87.5% Li ⁺ recovery rate while retaining 60.7% Li ⁺ purity from simulated GPW after 20 cycles, and further demonstrates applicability to real GPW. This work establishes a Li ⁺ ‐selective interfacial regulation strategy for efficient and stable lithium extraction and provides a material‐to‐process framework for sustainable lithium extraction from low‐quality aqueous lithium resources.