Fig. 1: Redox mechanism on the surface of Li2MnO3.
From: Highly reversible oxygen redox in layered compounds enabled by surface polyanions
a Crystal structure of Li2MnO3 (010) surface. The oxygen ions are divided into four layers from the outmost surface to the inner; each layer has the same number of O ions. The blue, green, and red/golden balls represent Mn, Li, and O ions, respectively. b Calculated LDOS of oxygen ions from the first layer to the fourth layer in the (001), (010), and (110) surfaces, respectively. The Fermi level is indicated by the dashed line. c Bader analysis of the surface O, inner O, and Mn ions of the three slabs in different delithiation states. Negative values of the change of Bader charge indicate electron loss of the ions. d Schematic diagram of various local atomic configurations, as well as the electronic structures and the calculated ELF. i, Oint, ii, Osur on the (001) surface, iii, Osur on the (010) surface and partial Osur on the (110) surface, iv, partial Osur on the (110) surface, v, oxygen ions in the second layer of the (001) surface, and vi, ELF values computed (isovalues of 0.7) for Oint and Osur in iii and iv. The hollow blue area, filled orange area, and filled light-orange area in each electronic state represents the empty antibonding (M–O)* band, O(2p) lone-pair band, and bonding (M–O) band, respectively.
