Polypyrrole membranes in fuel cells: insights into material properties and performance

Purpose The purpose of this paper is to outline replacements for conventional Nafion membranes for fuel cells that are plagued by high cost, biofouling and pH induced degradation. It targets the conducting polymer polypyrrole (Ppy) function in developing non-fluorinated polymer electrolyte membranes (PEM) as an adequate and superior replacement. Design/methodology/approach This is an integrative review. It critically evaluates and integrates existing scientific evidence on the use of polypyrrole (Ppy) in composite membranes for PEM fuel cells. The study is grounded on the method of how Ppy is used to modify and improve non-fluorinated base membranes’ characteristics. Findings The review finds composite membranes with polypyrrole (Ppy) to be very promising. It finds that Ppy enables proton transport channels to be formed at high temperature, enhances thermal and mechanical stability, provides corrosion protection to the bipolar plates and inhibits crossover of methanol. There are also serious limitations found, such as intrinsic low proton conductivity of Ppy, instability and complicated processing. Originality/value Originality in this review is the strict critical scrutiny of maximizing polypyrrole as a fuel cell material. It is greater than mere listing of benefits in that it transparently warrants future research requirements. This review stands out for the fact that it has a comprehensive list of ideas on how to improve, e.g. improving proton conductivity without compromising other characteristics, improving resistance to overoxidation and degradation, improving mechanical/thermal properties, making synthesis easy for scaling up and achieving regular morphology with controlled water uptake for engineering efficient membrane composites. The paper’s strength lies in its breadth and integrative approach – the review is not only surveys what has been done but also openly identifies challenges and future research opportunities.