Rationally Designed PU/CNFs/ZIF-8/PANI Composite Foams with Enhanced Flexibility and Capacitance for Flexible...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Cellulose nanofibers (CNFs)/MOF materials show promise for flexible energy storage due to porosity and flexibility.
• Conventional CNFs/MOFs often exhibit poor recoverability and plastic deformation, limiting device stability.

Purpose of the Study:

• To design a flexible composite foam with enhanced mechanical properties and electrochemical performance for energy storage devices.
• To address the limitations of poor recoverability and structural instability in existing flexible energy storage materials.

Main Methods:

• Fabrication of a polyurethane foam (PU)/CNFs/ZIF-8/polyaniline (PANI) composite using impregnation, in situ ZIF-8 growth, hot-pressing, and in situ aniline polymerization.
• Incorporation of carboxylated CNFs to enhance hydrophilicity and create a 3D network.
• Utilizing ZIF-8 as a sacrificial template to create hierarchical pores for improved ion transport and active material loading.

Main Results:

• The composite foam exhibited an interconnected micro-mesoporous structure with enhanced hydrophilicity and a stable 3D network.
• The electrode achieved a high specific capacitance of 449 F/g at 0.2 A/g with 97% retention after 2000 cycles at 5 A/g.
• The material demonstrated excellent mechanical flexibility with a tensile strength of 0.87 MPa and 230% elongation at break.

Conclusions:

• The developed PU/CNFs/ZIF-8/PANI composite foam offers a feasible approach for high-performance flexible supercapacitors.
• The synergistic architectural design provides a novel perspective for developing robust and portable energy storage devices.