| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem of increase in internal impedance by storage under a high temperature environment in a non-aqueous electrolyte secondary battery using lithium-nickel-containing compound oxide as a positive electrode active material. <P>SOLUTION: The positive electrode active material has lithium-containing oxide as expressed by a general formula Li<SB>a</SB>Ni<SB>1-x-y</SB>Co<SB>x</SB>M<SB>y</SB>O<SB>2</SB>(0.1≤x≤0.35, 0.05≤y≤0.25, M is one kind or more of metal element selected from Al, Ti, V, Cr, Mn, Fe or Y). When the positive electrode active material is turned into a charged state of a≤0.35, and an environmental temperature variable X-ray diffraction test is carried out by using CuKα beam, the diffraction peak of 2θ=18 to 20° measured at 200°C is shifted toward high angle side. <P>COPYRIGHT: (C)2007,JPO&INPIT |
