Alkaline polymer electrolyte fuel cells without anode humidification and H2 emission

Abstract Alkaline polymer electrolyte fuel cells (APEFCs) have a distinct merit of using nonprecious catalysts and thus attract tremendous research interest in the past decade. Current R&Ds of APEFCs have been focusing on the material stability and cell management. A particularly challenging problem is the water flooding in the anode, where large amounts of water are produced and cause a huge mass transport resistance to H2. Here we report a new strategy to address this problem. By applying a fluorine-containing ionomer (QAPAF), the hydrophobicity of the anode can be natively enhanced, and water flooding is no longer observed, which leads to a big gain in cell voltage up to 140 mV, in comparison to the cell with traditionally hydrophilic anode. With such improvements, the H2 gas can even be fed without humidification (0% RH), and the emission of the anode can also be completely sealed (dead-ended anode). In-situ electrochemical impedance spectroscopy (EIS) finds that even using dry H2, hydrophobic ionomer is beneficial to the water management and the cell performance. This work is a step towards the practical and economic APEFC technology.