Current Progress of Carbon Nanotubes Applied to Proton Exchange Membrane Fuel Cells: A Comprehensive Review

Fuel cells are promising electrochemical energy conversion devices with eco-friendliness and sustainability, while challenges have remained depending on their components. Meanwhile, researchers have paid significant attention to carbon nanotubes (CNTs) due to their excellent mechanical, thermal, electrical, morphological, and chemical properties. To meet this demand, suitable synthesis methods for CNTs have been naturally developed for large-scale production and proper application for devices. Also, numerous research efforts have been made to apply CNTs to ultimately improve fuel cell performance and durability. This review summarizes the brilliant strategies of CNTs that have been applied to pivotal components in fuel cells, such as catalysts, polymer electrolyte membranes (PEMs), gas diffusion layers (GDLs), and bipolar plates (BPs). Plus, this review provides a summary of methods that have been introduced for the synthesis and mass production of CNTs, like arc discharge, chemical vapor deposition (CVD), and laser ablation. Based on these proposed approaches in the literature, laid issues that need to be overcome for each component and what remarkable contribution occurred due to the application of CNTs in fuel cells are examined and discussed. In consequence, the application of CNTs in fuel cells still holds great potential for outstanding improvements in electrochemical performance and durability.