Advances in nanocellulose proton conductivity and applications in polymer electrolyte membrane fuel cells

Abstract

Fuel cells, crucial for the advancement of hydrogen-based energy devices, require novel materials for proton exchange membrane (PEM) that are more cost-effective and sustainable. At the core of such an energy source is the proton exchange membrane, which is made to be a good conductor for protons while isolating electrons to flow from the anode to the cathode, imprinting them with an external circuit and generating electricity in the process. Today, the most advanced fuel cell proton exchange membranes are perfluoro sulfonic acid-based (Nafion) membranes, which were initially developed more than 50 years ago. However, the scientific community has redirected its attention to creating next generation sustainable membranes based on natural materials, including nanocellulose, due to the many disadvantages associated with the use of NAFION membranes including high cost, high temperature degradation and environmental impact. Nanocellulose possesses unique characteristics like high mechanical strength, high tensile strength and more importantly renewability, which can be utilised towards fulfilling sustainability goals. Thus, we are of the opinion that a review of the most recent research on the applications of nanocellulose as a material for proton exchange membrane fuel cell components will be of much use in the advancement of this field. This review outlines the significant scientific advancements towards the applications of nanocellulose in polymer electrolyte membrane fuel cells. This analysis encompasses traditional cellulose, materials and films based on nanocellulose resources, polymer composites and blends and chemically altered nanocellulose. These advancements are thoroughly assessed, and intriguing results in the form of increase in proton conductivity and chemical stability are observed, which will further the research in this field towards commercializing nanocellulose in PEM fuel cells.