The effect of anion-sublattice structure on the displacement reaction in copper sulfide cathodes of rechargeable magnesium batteries

Abstract

Copper sulfides (Cu21xS, where x denotes position defects) with different structures of the S21 sublattice, such as cubic digenite and hexagonal chalcocite, have been investigated as cathode materials for magnesium (Mg) batteries. Rechargeable performance is only achieved using a cubic digenite cathode; however, using hexagonal chalcocite cathode yields poor rechargeable performance. The face-centered cubic S21 sublattice in cubic digenite, which enables Cu+ and Mg2+ ions to be displaced from each other without causing the lattice to collapse, could play a key role in improving the performance of rechargeable cathodes.