LiMnO/-MnO redox couple, possessing the advantage of high selectivity and intercalation capacity, is the most promising candidate for efficient electrochemically switched ion exchange (ESIX) from salt-lake brines. Currently Eh-pH diagrams are the main means for studying the dissolution mechanism of LiMnO/-MnO redox couple, however, the dissolution behavior obtained from experiments deviates significantly from the thermodynamic calculations. By introducing ionic strength correction into the thermodynamic calculation matrix of high salinity system, precise species distributions of Mn/Mn are successfully predicted, which are in good accordance with the experimental results. Based on the novel thermodynamic calculations, the strong dependence between pH and the dominant species of Mn/Mn is clarified, which in return determines the manganese dissolution (MD) behavior and intercalation capacity of the redox couple. The MD behavior differentiation between LiMnO and -MnO electrodes is induced by the electrode potential and pH. At pH > 5, high capacity (>30 mg/g) and low MD ratio (<0.1 %) can be achieved. This research sheds light on the existence status of Mn on the MD behavior and suggests the reasonable application range of ESIX with LiMnO/-MnO redox couple.

中文翻译：

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LiMn2O4/λ-MnO2 从卤水中选择性提取锂的高盐度系统的热力学校正

LiMnO/-MnO氧化还原对具有高选择性和插层能力的优点，是盐湖卤水高效电化学交换离子交换（ESIX）最有前途的候选材料。目前Eh-pH图是研究LiMnO/-MnO氧化还原电对溶解机理的主要手段，但实验得到的溶解行为与热力学计算存在较大偏差。通过在高盐体系热力学计算矩阵中引入离子强度修正，成功预测了Mn/Mn的精确物种分布，与实验结果吻合良好。基于新颖的热力学计算，阐明了 pH 值与 Mn/Mn 的主要物种之间的强烈依赖性，这反过来又决定了氧化还原对的锰溶解（MD）行为和嵌入能力。 LiMnO 和-MnO 电极之间的 MD 行为差异是由电极电位和 pH 引起的。当 pH > 5 时，可以实现高容量 (>30 mg/g) 和低 MD 比率 (<0.1 %)。该研究揭示了Mn对MD行为的存在状况，并提出了ESIX与LiMnO/-MnO氧化还原电对的合理应用范围。