Electrochemical quartz crystal microbalance study of lithium-ion dynamics in LiMn2O4/λ-MnO2 for ion-selective capacitive deionization
Lithium manganese oxide (LMO) has been widely utilized in capacitive deionization (CDI) for selective lithium extraction from salt-lake brines, owing to its excellent lithium intercalation capacity, selectivity, and recovery efficiency. However, due to the lack of an in-situ detection method, the LM...
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Veröffentlicht in: | Electrochimica acta 2025-02, Vol.513, p.145555, Article 145555 |
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Sprache: | eng |
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Zusammenfassung: | Lithium manganese oxide (LMO) has been widely utilized in capacitive deionization (CDI) for selective lithium extraction from salt-lake brines, owing to its excellent lithium intercalation capacity, selectivity, and recovery efficiency. However, due to the lack of an in-situ detection method, the LMO electrode kinetics in aqueous solution is mainly based on deductions and inferences. Here, electrochemical workstation-quartz crystal microbalance is utilized to study the lithium dynamics in LiMn2O4/λ-MnO2 in aqueous system for the first time. In-situ electrochemical analysis verifies that the lithium intercalation and deintercalation during the redox of LiMn2O4/λ-MnO2 is a one-electron transfer quasi-reversible process. The intermediate phase, i.e., Li0.5Mn3+0.5Mn4+1.5O4 with P213 space group and layered structure, is first identified in between LiMn2O4 and λ-MnO2 with Fd3¯m space group and spinel structures in the aqueous system. Li+ occupies the 4a and 8a sites, respectively, in Li0.5Mn3+0.5Mn4+1.5O4 and LiMn2O4. Also, the spontaneous lithiation of λ-MnO2 and faster lithiation kinetics than that of delithiation is clarified with electrochemical analyses. This research utilized the in-situ research means to interpret the lithium dynamics during the lithiation and delithiation process, which sheds light on the issues on which there is no consensus.
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ISSN: | 0013-4686 |
DOI: | 10.1016/j.electacta.2024.145555 |