Constructing vertical proton transport channels in proton exchange membranes of fuel cells

Ion-conducting electrolyte membranes are essential parts of electrochemical energy storage devices like fuel cells and are crucial for energy conversion. However, the most widely used proton exchange membranes - Nafion, have problems such as strong dependence of conductivity on temperature and humidity, high cost and complex synthesis. So, researchers have been working to improve the comprehensive performance of membranes, including conductivity, stability, mechanical strength, and durability. To do this, the membrane structure must be maximized, which calls for applying the appropriate techniques to produce microstructure with excellent order, periodicity and connection. The development of vertical proton transport channels in the membrane will break through the limitation of raw materials and shorten the proton transport path. This will dramatically improve the proton conductivity in theory because protons are carried across membranes. Besides, different fillers and methods can also affect the fuel permeability, mechanical strength, and durability of the membrane. This research examines six technical approaches for building vertical channels around proton exchange membranes, including the nanofiber, electric field, magnetic field, template, heat treatment, and other approaches. The article summarizes relevant studies and practical uses, evaluates existing challenges and their remedies, and offers a projection of forthcoming progress.