Ions Conduction in pH Stable Interpenetrated-Catenated Metal-Organic Framework

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are porous materials with tunable structures.
• Ionic conduction in MOFs is crucial for energy applications.
• Developing MOFs with high conductivity and stability remains a challenge.

Purpose of the Study:

• To design and synthesize a novel MOF with interpenetrated and catenated 3D+2D→3D structure.
• To investigate the ionic conduction properties of the MOF and its derivatives.
• To explore the effect of guest molecule encapsulation on conductivity.

Main Methods:

• Synthesis of a new MOF {[Cd4(dim)4(dht)4(H2O)4](Sol)x}n (1).
• Modification of the MOF to create a bare pore derivative (1').
• Encapsulation of guest molecules (NH3, HCl, KOH) into the pores of 1'.
• Measurement of ionic conductivity under various temperature and humidity conditions.

Main Results:

• The MOF exhibits extreme pH stability and a unique network structure.
• The bare pore derivative (1') shows structural flexibility and large accessible pores.
• Encapsulated MOFs (1'@NH3, 1'@HCl, 1'@KOH) display enhanced proton and hydroxide ion conductivity.
• 1'@HCl achieves a record proton conductivity of 6.8 × 10⁻¹ S cm⁻¹ at 30°C and 95% RH.
• 1'@KOH shows high hydroxide ion conductivity, reaching 7.6 × 10⁻¹ S cm⁻¹ at 80°C and 95% RH.

Conclusions:

• The developed MOF is a promising material for efficient ionic conduction.
• Guest molecule encapsulation is an effective strategy to enhance ionic conductivity in MOFs.
• The MOF derivatives show potential for applications in electrochemical devices and sensors.