Electrode material for lithium secondary battery, electrode structure and lithium secondary battery

摘要

An electrode material for a lithium secondary battery which includes particles each having a central portion and a surface portion covering the surface of the central portion. A distance from a center to an outermost surface of the particle is occupied 80 to 99% by the central portion and 1 to 20% by the surface portion. The central portion includes LiM_1-aD_aO₂ having an alpha-NaFeO₂ structure, and the surface portion includes LiM_1-bE_bO₂ having an alpha-NaFeO₂ structure. (M is C or Ni; D is a transition metal element or Al replacing a part of Co or Ni as M; E is a metal element replacing a part of Co or Ni as M; and M is not the same as D or E.) The following relationships are satisfied in the central portion, in terms of atomic ratio: D/(M+D+E)<0.05 and E/(M+D+E)<0.05.