[Kevmo]

Sounds like a Patterson cell?

Construction

https://en.wikipedia.org/wiki/Patterson_power_cell

The cell has a non-conductive housing. The cathode is composed of thousands of sub-millimeter microspheres (co-polymer beads), with a flash coat of copper and multiple layers of electrolytically deposited thin film (650 Angstrom) nickel and palladium. The beads are submerged in water with a lithium sulfate[2] (Li2SO4) electrolyte solution.

[Wonder Warthog]

"...with a flash coat of copper and multiple layers of electrolytically deposited thin film (650 Angstrom) nickel and palladium."

With the Patterson cell, only the metal layers are electrolytically deposited, not both deuterium and palladium simultaneously per SPAWAR.