TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The spherical active materials and/or the planular active materials include one or more of metal complex of formulae (LiCoaM11-aO2), (Li1+bNicCo1-c-dM2dO2), (Li1+e(MnfNigCo1-f-g-hM3h)1-eO2), (LiM4PO4) or (LiiMn2-jM5jOkFm).M1 = one or more of Mg, Al or Ba;a = 0 or 1;M2 = one or more of Mg, Al, Mn or Ba;b-d = 0-0.1, where sum of c+d is 0 or 1;M3 = one or more of Mg, Al, Zn, Ti or V;e = 0.05-0.25;f = 0.5-0.7;g = 0-(1-f);h = 0.001-0.05;M4 = one or more of Fe, Mn or Co;M5 = one or more of Co, Ni, Mg, Al, B, Ti, V, Cr, Fe, Cu, Zn, Mo, Sn, Ca, Sr or W;i = 0.9-1.1;j = 0-0.6;k = 3.7-4.1; andm = 0-0.1.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The cathode active material layer includes a first layer and a second layer, where the first layer includes the spherical active materials, and the second layer includes the planular active materials. The spherical active materials have an average degree of circularity that is higher than an average degree of circularity of the planular active materials. The spherical active materials have an average degree of circularity that is greater than or equal to 0.6, and the planular active materials have an average degree of circularity that is less than or equal to 0.2. The average particle diameter of the primary particles of the spherical active materials is larger than 0.1 mu m and is smaller than 30 mu m, and the average particle diameter of the primary particles of the planular active materials is larger than 0.01 mu m and is smaller than 1 mu m. The first layer has a thickness that is smaller than a thickness of the second layer. The first layer includes a first binder, a ratio of a content of the first binder with respect to a total content of the spherical active materials and the first binder in the first layer is greater than 0.5 wt.% and less than 5 wt.%, the second layer includes a second binder, and a ratio of a content of the second binder with respect to a total content of the planular active materials and the second binder in the second layer is greater than 2 wt.% and less than 10 wt.%. The secondary battery is a lithium ion secondary battery.