The cover picture shows a schematic illustration of an ammonia-fueled solid oxide fuel cell stack. The supplied ammonia fuel is first decomposed into hydrogen and nitrogen in the Ni-YSZ porous anode and then the produced hydrogen electrochemically reacts with oxide ion to generate electric power. The stack consists of 30 anode-supported planar cells with an active area of 95 cm². The output power of over 1 kW and 1,000 h durability have been achieved.

The cover picture shows how casting irregularities, such as air bubbles and cracks, located within a polymer electrolyte membrane (middle) were studied employing two diagnostic techniques. Spatial performance experiments were conducted using a segmented fuel cell system (bottom), and thermal imaging was performed to map hydrogen crossover to the spatial performance results (top). The work assists the decision if certain membrane irregularities can be tolerated or need to be classified as defects. It contributes to the development of threshold detection limits for in-line quality control diagnostics.