A New Frontier Towards Development of Efficient SPEEK Polymer Membranes for PEM Fuel Cells Applications: A Review

Abstract

Proton exchange membrane fuel cells (PEMFCs) have gained popularity over the last decade as a potential clean energy source for electric vehicles and portable electronic devices. Nafion® membranes are commonly used as membrane material but suffers from high methanol crossover and cost. These drawbacks negatively influence the widespread commercial application of PEMFCs. Currently, the focus is on developing high-performance, low-cost PEMs to replace Nafion® membranes. Sulfonated poly-ether-ketone-ether (SPEEK) has been identified as a promising alternative PEM in fuel cell applications due to its advantageous properties, such as low cost, mechanical and chemical stability, and ease of preparation and operation. The main purpose of this review is to demonstrate the benefits of SPEEK-based composite membranes over Nafion® by mixing the SPEEK material with fluorinated polymers, hydrocarbon polymers, carbon-based materials, metal oxide materials, etc. The ion-exchange capacity and proton conductivity of SPEEK polymer with different fillers are highlighted. SPEEK-based composite membranes are far more suitable for PEMFC and DMFC applications because SPEEK polymer is produced in an environmentally friendly manner. This critical review serves to guide researchers in developing processes to maximize the SPEEK-based membrane’s properties for fuel cells applications.