PANa/Covalent organic framework composites with improved water uptake and proton conductivity

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Proton conductivity in materials is crucial for energy applications.
• Loading proton carriers effectively into covalent organic frameworks (COFs) remains a challenge.
• Enhancing water molecule enrichment in COFs can improve proton conductivity.

Purpose of the Study:

• To develop COF-based composites with enhanced proton conductivity.
• To investigate the role of sodium polyacrylate (PANa) in improving water retention within COF channels.
• To establish a new method for improving water content in COF channels for better proton conduction.

Main Methods:

• Synthesized COF-based composites (PANa@UCOF-x) using an in situ reaction strategy.
• Coated varying proportions of superabsorbent PANa onto the COF surface.
• Measured proton conductivity of the composites at 80 °C and 95% relative humidity.

Main Results:

• PANa@UCOF-x composites exhibited significantly enhanced proton conductivity compared to pristine UCOF.
• Proton conductivity reached up to 1.1 × 10⁻¹ S cm⁻¹ for PANa@UCOF-40.
• The conductivity of PANa@UCOF-x was 4-5 orders of magnitude higher than the original UCOF (7.4 × 10⁻⁷ S cm⁻¹).
• PANa effectively enhanced water molecule enrichment in the 1D channels of COFs.

Conclusions:

• The developed PANa@UCOF-x composites demonstrate superprotonic conduction.
• The study highlights the importance of ordered channels in constructing effective proton conduction pathways.
• This work presents a novel approach to improve water content in COFs for enhanced proton conductivity.