Spinel-type lithium cobalt manganese-containing complex oxide
There is provided a Co-based 5-V spinel-type lithium manganese-containing complex oxide not only having an operating potential of 4.5 V or higher but also being capable of extending its capacity region of a 5.5 to 5.5 V region and being capable of enhancing its energy density as well. There is proposed a spinel-type lithium cobalt manganese-containing complex oxide having a crystal structure classified as a space group Fd-3m and being represented by the general formula [Li x (Co y Mn 3−x−y )O 4−δ] (wherein 0.90≦x≦1.15 and 0.75≦y≦1.25), wherein the oxide has a crystallite size measured by a Rietveld method using the fundamental method of 100 nm to 200 nm, an interatomic distance of Li—O of 1.80 Å to 2.00 Å, and a strain of 0.20 to 0.50.
1. A spinel-type lithium cobalt manganese-containing complex oxide, having a crystal structure classified as a space group Fd-3m and being represented by a general formula [Li x (Co y M z Mn 3−x−y−z )O 4−δ ], wherein 0.90≦x≦1.15, 0.90≦y 1.25 and 0<z≦0.3, wherein M is Ni or a combination of Ni with one or two or more elements selected from the group consisting of Mg, Ti, Al, Ba, Cr, Fe, Mo, W, Zr, Y and Nb, and wherein 0≦δ<4 wherein the spinel-type lithium cobalt manganese-containing complex oxide has a crystallite size measured by a Rietveld method using a fundamental method of 100 nm to 200 nm, an interatomic distance of Li—O of 1.80 Å to 2.00 Å, and a strain of 0.20 to 0.50, and wherein the spinel-type lithium cobalt manganese-containing complex oxide has an operating potential of 4.5 V or higher at a metal Li reference potential.
2. A lithium secondary cell, comprising a spinel-type lithium cobalt manganese-containing complex oxide according to claim 1 as a positive electrode active substance thereof.