Molten salt electrodeposition enabling direct and efficient preparation of homogeneous Pb-Li eutectic alloys

Abstract

Liquid lead-lithium (Pb-Li) alloys are promising tritium breeder materials for nuclear fusion, but conventional high-temperature smelting preparation process remains hampered by low efficiency, compositional segregation, and safety risks from metallic Li feedstocks. Herein, we propose a molten salt electrodeposition strategy using a liquid Pb metal electrode to directly produce Pb-Li alloys. Driven by in-situ alloying and depolarization effects, Li⁺ ions from LiCl-KCl molten salts undergo underpotential deposition on the liquid Pb cathode, which enhances current efficiency and reduces electrolysis energy consumption. Homogeneous Pb-Li alloys are stably obtained across a wide range of conditions, including Li content (10–35 at%), current density (100–500 mA·cm⁻²), and temperature (400–550 °C), with current efficiencies consistently maintained above 80 %. A kilogram-scale experiment validates that potential-feedback galvanostatic electrodeposition enables precise synthesis of Pb-Li eutectic alloys with an average Li content of 17.10 ± 0.80 at %, reducing carbon emissions by 83.9 kg CO₂e·t⁻¹-alloy and lowering production costs by $143.6 per ton alloy compared to smelting. This approach exhibits stability, sustainability, and scalability for precisely fabricating homogeneous Pb-Li and analogous Li-based alloys.