H Induced Metal‐Insulation Transition Boosts the Stability of High Temperature Polymer Electrolyte Membrane Fuel Cells

Abstract High temperature polymer electrolyte membrane fuel cells (HT‐PEMFCs) have garnered significant attention due to their expanded range of hydrogen sources and simplified management systems. However, the frequent start‐up and shut‐down (SU/SD) caused fuel starvation operation condition seriously deteriorates the performance and lifetime of the fuel cell. In this manuscript, VO 2 was incorporated in the anode to restrain fuel starvation of the electrode. Under the operation condition, the insulative VO 2 would reversibly transform into metallic H x VO 2 by intercalating hydrogen, and H x VO 2 can automatically release hydrogen, which could act as the hydrogen buffer and suppress reverse‐current degradation. After the hydrogen release, the generated insulating VO 2 would prevent the side reactions during fuel starvation. Compared to the traditional Pt anode, the electrode with VO 2 showed much higher output power and greatly improved durability after fuel starvation. This work demonstrates the in situ reversible hydrogen storage/release‐controlled metal‐insulator phase transition strategy to enhance the durability of fuel cells.