Recent advances in additive-enhanced polymer electrolyte membrane properties in fuel cell applications: An overview

Additives such as fillers, cross-linkers, and plasticizers have become increasingly important in the polymer nanocomposite production field, especially for enhancing the structural morphology, functional behavior, and final performance of nanocomposites in broad applications. The current work is an overview of the effects of additive substances such as fillers, cross-linkers, and plasticizers in the polymer electrolyte membrane composites applied to fuel cells. A comparative review is conducted by categorizing fillers into several types, and the most popular cross-linkers and plasticizers used in fuel cell membranes are included in this review. The highlighted properties include the proton conductivity, permeability, mechanical properties, thermal properties, crystallinity, and structure of additive-modified nanocomposites. Furthermore, the challenges and future prospects in the additive field are discussed in Section 5.0. This review can provide a reference for researchers seeking specific substances that can be used to enhance nanocomposite properties, especially in membrane fuel cell applications.