A review of porous polytetrafluoroethylene reinforced sulfonic acid-based proton exchange membranes for fuel cells

Porous polytetrafluoroethylene (PTFE) reinforced sulfonic acid-based proton exchange membranes (PEMs) are widely used for proton exchange membrane fuel cells (PEMFCs) due to their superior mechanical durability compared with pristine/free-standing sulfonic acid-based PEMs. However, the development of advanced porous PTFE reinforced sulfonic acid-based PEMs (PTFE-PEMs) still faces some technical challenges, including poor ionomer filling, poor interface bonding between PTFE skeleton and ionomer, limited chemical durability, inferior performance at low humidity, limited interface combination between PTFE-PEMs and catalyst layers, and unclear effect of the number of PTFE skeleton layers. Extensive research has been implemented to overcome these scientific issues, thus realizing the practical prospects of PTFE-PEMs. Nevertheless, relevant summary about these studies is scarce. On this basis, this paper highlights the technical challenges of PTFE-PEMs and reviews the research advances in solving these scientific issues of PTFE-PEMs. In addition, the challenges and future perspectives of PTFE-PEMs are also discussed. The systematic summary and proposed directions can trigger thoughts and provide ways to reasonably design PTFE-PEMs for PEMFCs in the near future.