Sulfonated Cobalt Metal-Organic Framework Embedded Mixed Matrix Membrane towards Fuel-Cell Applications

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Poly(2,5-benzimidazole) (ABPBI) membranes are essential for proton-exchange membrane fuel cells (PEMFCs).
• Enhancing the proton conductivity and mechanical properties of ABPBI is critical for improved fuel cell efficiency.
• Functionalized metal-organic frameworks (MOFs) offer potential for composite membrane development.

Purpose of the Study:

• To develop enhanced proton-exchange membranes (PEMs) for H₂-O₂ fuel cells.
• To investigate the effect of incorporating sulfonated cobalt metal-organic framework (sCo-MOF) into ABPBI membranes.
• To evaluate the fuel cell performance of the resulting composite membranes.

Main Methods:

• ABPBI membranes were synthesized via polycondensation.
• Various proportions of sCo-MOF were incorporated into ABPBI to form composite membranes.
• Composite membranes were sulfonated using sulfuric acid and characterized for properties and fuel cell performance.

Main Results:

• Composite membranes exhibited improved proton conductivity, tensile strength, and physicochemical properties compared to pristine ABPBI.
• A membrane with 4 wt% sCo-MOF showed high water uptake (23.25%) and ion-exchange capacity (2.89 mequiv g^-1).
• The 4 wt% sCo-MOF/sABPBI membrane achieved a power density of 415.8 mW cm^-2 at 80 °C, significantly outperforming the sABPBI membrane (178.6 mW cm^-2).

Conclusions:

• The incorporation of sCo-MOF into ABPBI membranes is an effective strategy for enhancing proton conductivity and fuel cell performance.
• The developed composite membranes show promise for efficient and durable H₂-O₂ fuel cell applications.
• Further research can explore different MOF functionalizations and loadings for optimized PEMFCs.