Ligand Engineering Toward Robust Sodium Storage in Self-Supported Metal-Organic Frameworks

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Rapidly charging and durable sodium-ion batteries are needed to replace lithium-ion batteries.
• Large sodium ions (Na+) require significant space for accommodation in battery anodes.
• Metal-organic frameworks (MOFs) show potential as anode materials, with performance influenced by organic ligands.

Purpose of the Study:

• To engineer metal-organic frameworks (MOFs) with enhanced sodium storage capacity.
• To investigate the role of ligand structure in MOF performance for sodium-ion batteries.
• To develop binder-free anode materials for efficient sodium storage.

Main Methods:

• Ligand engineering using large conjugated naphthalene-2,6-dicarboxylic acid.
• Fabrication of self-supported MOF arrays.
• Electrochemical testing of MOFs as binder-free anodes for sodium storage.

Main Results:

• MOFs with long, conjugated aromatic ligands demonstrated robust sodium storage.
• The engineered MOFs provided ample sites for Na+ accommodation, leading to high reversible capacity.
• Achieved a high capacity of 330 mAh g⁻¹ at 1000 mA g⁻¹ with excellent rate capability and cycling stability.

Conclusions:

• Ligand engineering is an effective strategy for designing high-capacity MOF materials for sodium storage.
• The developed MOFs show promise as binder-free anodes for next-generation sodium-ion batteries.
• This approach offers potential for broad applications in energy storage systems.