Revealing the functional relationship between manganese dissolution potentials and lithium concentrations with diffusion coefficient for lithium intercalation in λ-MnO2 electrode

Abstract

Electrochemical redox lithium extraction (ELE) with LiMn₂O₄/λ-MnO₂ redox couple, stands out as the most prospective technology for efficient and selective lithium extraction from the salt lake brines owing to the high lithium intercalation capacity, selectivity, and recovery rate. However, the decreasing Li⁺ concentration induced electrode polarization, especially, at low concentrations, and inappropriately applied potentials can significantly accelerate manganese dissolution (MD). While no correlational research has established the relationship between the manganese dissolution potential (E_MD) and Li⁺ concentration gradient. Herein, the inversely proportional relationship between E_MD and the lithium concentration is first revealed through steady-state diffusion coefficients. This research sheds light on the MD mechanism at different lithium concentration gradients and lays the foundation for the industrial application of electrochemical lithium extraction with LiMn₂O₄/λ-MnO₂ redox couple from salt lake brines.