Intensified Interfacial Charge Boost Electrochemical Lithium Extraction from West Taijinar Brine by LiMn₂O₄

The increasing imbalance between the global lithium supply and demand underscores the urgent need for efficient extraction technologies. LiMn2O4 (LMO) has emerged as a promising candidate for electrochemical lithium extraction due to its environmental compatibility, energy efficiency, and operational simplicity. This study highlights the critical role of interfacial charge in governing Li+ migration, adsorption selectivity, and charge transfer behavior. By anchoring MnPO4(MP) onto LMO via a sol–gel approach, phosphate-driven interfacial charge regulation is achieved, significantly enhancing the material’s zeta potential (from −19.48 to −31.32 mV at pH = 6) and surface hydrophilicity (contact angle reduced from 20.2° to 18.5°). The modified material (2MP-LMO) exhibits improved Li+ diffusion kinetics, delivering a high extraction capacity of 30.59 mg·g–1·h–1 in lithium-rich mother liquor while reducing the level of Mn dissolution by 24.1%. Moreover, in high-impurity West Taijinar brine, 2MP-LMO achieves a Li+ release capacity of 35.08 mg·g–1·h–1, demonstrating excellent selectivity and operational stability. These findings underscore the effectiveness of interfacial charge modulation in enhancing electrochemical lithium extraction performance and its potential for scalable applications in complex brine systems.