Electrodeposition of metals in microgravity conditions

Metal electrodeposition may produce irregular deposits with various morphologies. For liquid electrolytes a precise study of these deposits may be complicated by convective motion due to buoyancy. Microgravity conditions give a straightforward mean to avoid this effect: we present here a study of electrodeposition in the microgravity environment provided by parabolic flights. Two electrochemical systems were studied: copper deposition from copper sulfate aqueous solution and lithium deposition from an ionic liquid containing LiTFSI. Concentration variations in the electrolyte were measured by laser interferometry. For copper, concentration variations were in good agreement with theory. For lithium, an induction time was observed for the concentration evolution in ground experiments: due to this induction time and to the low diffusion coefficient in ionic liquid, concentration variations were hardly measurable during the 20s parabolic flight.