A wet electrolytic capacitor that contains a casing within which is positioned an anode formed from an anodically oxidized sintered porous body and a fluidic working electrolyte is provided. The casing contains a metal substrate over which is disposed a hydrogen protection layer that contains a plurality of sintered agglomerates formed from a valve metal composition. The present inventors have discovered that through careful selection of the relative particle size and distribution of the agglomerates, the resulting protection layer can effectively absorb and dissipate hydrogen radicals generated during use and/or production of the capacitor, which could otherwise lead to embrittlement and cracking of the metal substrate.