Material Challenges and Developments for High-Temperature Methanol Fuel Cells

While of significant value in supplying sustainable electricity for mobile and stationary use, the large-scale application of direct methanol fuel cells (DMFCs) is an ongoing challenge. DMFCs make use of methanol oxidation (MOR) on the anode and oxygen reduction (ORR) on the cathode, with the two reaction chambers being separated by an ion-conducting membrane. Broad application is hindered by material limitations due to sluggish kinetics on the anode, as the MOR involves six electrons, as well as limited temperature stability and methanol crossover of conventional membrane materials. Their temperature resistance also restricts the temperature in the fuel cell, which otherwise could be increased to overcome the kinetic limitations of the anode. As the large-scale application of DMFCs holds a high potential to contribute significantly to a sustainable energy infrastructure, the efforts and ideas in material development are reviewed to achieve highly active, durable, and stable anode catalysts as well as membrane materials, opening the temperature window up to 200 °C. This review reveals the advantageous catalytic properties of intermetallic catalysts as anode materials and lays out polybenzimidazoles as simple yet modular membrane materials.