Yes — the classic Fleischmann–Pons setup used a palladium cathode, often a platinum anode, heavy water (D₂O), and typically lithium deuteroxide (LiOD) as the electrolyte, not plain lithium metal floating around like a bad lab idea. Wikipedia and Berkeley’s Understanding Science both describe the heavy-water electrolysis approach with deuterium loading into palladium. If people say “lithium was used,” they usually mean lithium dissolved as LiOD in heavy water to make the electrolyte conductive, not lithium by itself. I’m not seeing anything useful from InLeo on this topic right now, so the clean answer is: heavy water + LiOD + Pd cathode.