| 摘要 |
[Object] To provide a means, in an electric device such as a lithium ion secondary battery, whereby reduction in battery capacity as a charge and discharge cycle progresses can be suppressed (i.e. , cycle durability can be improved), even if an electrolyte contains a cyclic sulfonic acid ester as an additive. [Solving Means] Disclosed is an electric device having a power generating element containing a positive electrode in which a positive electrode active material layer containing a positive electrode active material is formed on a surface of a positive electrode current collector, a negative electrode in which a negative electrode active material layer containing a negative electrode active material is formed on a surface of a negative electrode current collector, and a separator containing an electrolyte. The positive electrode active material is made to contain a lithium nickel-based composite oxide having a layered crystal structure which is capable of insertion and desorption of lithium ions, having a composition represented by the general formula: ([Li ± Ni ² ] 3a [Ni x Mn y-r M r CO z ] 3b O 2 ) (provided that M is at least one selected from the group consisting of Ti, Zr, Nb, W, P, Al, Mg, V, Ca, Sr, Cr, Fe, B, Ga, In, Si, Mo, Y, Sn, V, Cu, Ag, and Zn, and x + y + z ‰¤ 1, ² ‰¤ 0.032, 0.9 ‰¤ ± + ² ‰¤ 1.2, 0 < x < 1, 0 < y < 1, 0 < z < 1, and 0 ‰¤ r ‰¤ 0.3 are satisfied), and the electrolyte is made to contain a cyclic sulfonic acid ester. |
