Lithium ruthenate, Li2RuO(IV)3, or LRO, is a chemical compound of lithium, ruthenium and oxygen. It has a layered honeycomb crystal structure, and can be prepared by direct calcination of Ru metal or RuO2 and lithium carbonate at ca. 700 °C. The material is a potential lithium-ion battery electrode material and supercapacitor because of its high specific capacity due to lattice oxygen redox. This application is hindered by the high costs of Ru, as compared to the cheaper Li2MnO3 alternative
Despite having a low-spin state of Ru(IV), namely 4d4, above 540 K there have been observed Ru-Ru dimers which decrease the magnetic susceptibility of the material.
The compound is known to react with water in neutral and basic solutions to partially exchange Li2O with H2O in its structure. The new phase, Li2-xHxRuO3, is structurally different from pure Li2RuO3.
The delithiathed phase, Li2-xRuO3, is nonstoichiometric. It exhibits Ru4+-Ru4+ dimers and above 539 K has increase in magnetic susceptibility.Jimenez-Segura, Marco-Polo; Ikeda, Atsutoshi; Kimber, Simon A. J.; Giacobbe, Carlotta; Yonezawa, Shingo; Maeno, Yoshiteru . (2016). Effect of delithiation on the dimer transition of the honeycomb-lattice ruthenate. Physical Review B, 94(11), 115163–. doi:10.1103/PhysRevB.94.115163
Other phases While Li2RuO3 could be obtained from mixing Li2CO3 and RuO2 at 800°C, when the same mixture is heated at 900°C, another ruthenate, Li3Ru(V)O4,Alexander, A.; Battle, P. D.; Burley, J. C.; Gallon, Daniel J.; Grey, Clare P.; Kim, S. H. . (2003). Structural and magnetic properties of Li3RuO4. Journal of Materials Chemistry, 13(10), 2612–. doi:10.1039/b305220f is obtained. Li7RuO6Chem. Mater. 2022, 34, 8, 3724–3735 and the cubic NaCl-like LixRuO1+xHirohiko Sato; Makoto Soma. (2007). Spin-glass ruthenate: Cubic-. , 310(2-part-P2), 1517–1519. doi:10.1016/j.jmmm.2006.10.658 have also been reported.
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