A Quinoidal Two-Dimensional Metal-Organic Framework for High-Performance Micro-Supercapacitors and Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Two-dimensional (2D) metal-organic frameworks (MOFs) are crucial for energy storage due to their tunable structures.
• Integrating redox-active linkers in 2D MOFs enhances charge storage and ion transport.
• Existing MOFs often face limitations in processability and energy density for practical applications.

Purpose of the Study:

• To synthesize and characterize novel 2D MOFs using a quinoidal dicarboxylate ligand for microscale energy storage.
• To investigate the electrochemical properties and performance of these MOFs in energy storage devices.
• To demonstrate the potential of these MOFs as components in miniature and solid-state energy storage systems.

Main Methods:

• Synthesis of a quinoidal dicarboxylate ligand (AQM-H2L) and its coordination with Cu2+ and Zn2+ ions.
• Characterization of the resulting crystalline MOFs and exfoliated nanosheets using techniques like X-ray diffraction and electron microscopy.
• Fabrication of energy storage devices, including supercapacitors integrated with graphene and solid-state batteries utilizing MOFs as electrolyte additives.

Main Results:

• The copper-based MOF (AQM-AQM-H2L-Cu) showed layered structures with significant pseudocapacitance from Cu2+/Cu+ redox activity.
• Exfoliated MOF nanosheets (approx. 5 nm) maintained crystallinity and processability.
• Supercapacitors achieved high areal and volumetric capacitances (29.6 mF cm-2 and 18.1 F cm-3), with an energy density of 2.6 mWh cm-3.
• In solid-state batteries, 1 wt% MOF nanosheets enhanced LiFePO4 cell performance, delivering 169.8 mAh g-1 at 0.2 C with 93% capacity retention over 400 cycles.

Conclusions:

• Quinoidal linkers are effective in creating ionically active 2D frameworks for energy storage.
• The developed MOFs offer a promising design for high-performance miniature and solid-state energy devices.
• This research paves the way for next-generation energy storage solutions using advanced MOF materials.