Efficient room-temperature neodymium electrodeposition in calcium-based electrolyte 

Cyclic voltammograms of 0.45M Ca(BH4)2 electrolyte system, at Nd3+ concentrations of 0, 15 and 70mM.
Cyclic voltammograms of 0.45M Ca(BH4)2 electrolyte system, at Nd3+ concentrations of 0, 15 and 70mM.

CMI researchers from Idaho National Laboratory conducted the research for this highlight.

Innovation
More sustainable electrolyte for room temperature rare earth metal electrodeposition.

Achievement
Calcium borohydride electrolyte demonstrated promising Nd deposition metrics, including faradaic efficiency approaching 85%, deposition rate 1mA/cm2, Nd purity >90% (metal basis). However, XPS analysis of recovered bulk electrodeposit suggested presence of Nd0 and Nd3+.

Significance and Impact

  • System is water-free and fluoride-free, eliminating associated environmental hazards and emissions. 
  • New electrolyte uses abundant alkaline-earth metal and is more cost-effective than previously reported Li-based electrolyte.
  • Currently working to improve deposition rate while mitigating alteration of deposited Nd metal.

Hub Target Addressed 
Low temperature electrochemical rare earth metal production.

High resolution XPS spectra in Nd3d region of commercial Nd foil and Nd electrodeposit, with and without surface sputtering
High resolution XPS spectra in Nd3d region of commercial Nd foil and Nd electrodeposit, with and without surface sputtering