Stoichiometry of LiNiO2 studied by Mössbauer spectroscopy

From the 61Ni and 57Fe Mössbauer spectroscopy data follows the cationic site assignment in Li1–x Ni1+x O2. Our data explain the ferromagnetic properties of this material because of the appearance of Ni2+ (S=1) among Ni3+ (S=1/2) in Ni3+O2 hexagonal planes. We have no evidence for the ferromagnetic interaction between the NiO2 layers through the excess Ni2+ ions substituting the Li+ ions. The presence of Ni2+ found in the Ni3+O2 planes explains the absence of the Jahn–Teller distortions probably because of the electronic transfer between the Ni3+ and Ni2+ ions