New rock salt-related oxides Li3M2RuO6 (M=Co, Ni): Synthesis, structure, magnetism and electrochemistry

Two new rock salt related oxides of formula, Li3M2RuO6, (M=Co, Ni) have been prepared. The M=Co oxide adopts the LiCoO2 (R-3m) structure and the M=Ni oxide adopts a similar layered structure related to Li2TiO3, monoclinic (C2/c), with partial mixing of Li and Ni/Ru atoms. For Li3Co2RuO6, oxidation state for Ru is 4+ and antiferromagnetic (AFM) order is found below 10 K while for the analogous Li3Ni2RuO6 , Ru oxidation state is 5+ and a ferrimagnetic (FM) behavior with a Curie temperature of 100 K is found. Electrochemical studies correlate well with both magnetic properties and crystal structure.