Heterostructure-Engineered Conductive MOFs Coupled with MoSe₂@MXene Framework for Efficient and Selective Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Sustainable lithium recovery from salt lake brines is crucial for clean energy but faces challenges from low Li+ concentrations and Mg2+ interference.
• Capacitive deionization (CDI) is a promising technology for ion separation, but requires advanced electrode materials for efficient lithium extraction.

Purpose of the Study:

• To develop a highly efficient and selective electrode material for lithium extraction from brines using CDI technology.
• To engineer a heterostructure composite that enhances lithium capture capacity, adsorption rate, and selectivity.

Main Methods:

• Fabrication of a ternary composite electrode: conductive metal-organic frameworks (c-MOFs) with a MoSe2@MXene framework (Fe-THBQ@MoSe2@MXene).
• Characterization using X-ray absorption spectroscopy (XAS) and ex situ X-ray diffraction (XRD).
• Performance evaluation in model solutions and real brine, including electrochemical tests and density functional theory (DFT) calculations.

Main Results:

• The Fe-THBQ@MoSe2@MXene electrode exhibited high Li+ capture capacity (4.05 mmol g-1) and ultrafast adsorption rate (0.98 mmol g-1 min-1).
• Exceptional Li+ selectivity was achieved, even with high Mg/Li ratios, demonstrated in both model solutions and real brine.
• The material showed superior cycling stability (91.3% retention after 50 cycles) and a dual Li+ storage mechanism.

Conclusions:

• The developed heterostructure composite offers a promising strategy for efficient and selective lithium recovery via CDI.
• The synergistic effects between c-MOFs and the MoSe2@MXene framework enhance conductivity, ion transport, and selectivity.
• This work provides a rational design approach for advanced CDI materials in sustainable lithium resource management.