Surface stability of spinel MgNi0.5Mn1.5O4 and MgMn2O4 as cathode materials for magnesium ion batteries.

Rechargeable ion batteries based on the intercalation of multivalent ions are attractive due to their high energy density and structural stability. Surface of cathode materials plays an important role for the electrochemical performance of the rechargeable ion batteries. In this work we calculated surface energies of (001), (110) and (111) facets with different terminations in spinel MgMn 2 O 4 and MgNi 0.5 Mn 1.5 O 4 cathodes. Results showed clearly that atomic reconstruction occurred due to surface relaxation. The surface energies for the (001), (110) and (111) surfaces of the MgNi 0.5 Mn 1.5 O 4 were 0.08, 0.13 and 0.11 J/m 2 , respectively, whereas those of the Ni-doped MgMn 2 O 4 showed less dependence on the surface structures. [ABSTRACT FROM AUTHOR]