Positive electrode active material for nonaqueous electrolyte secondary battery, positive electrode and secondary battery

摘要

Provided is a cathode active material for nonaqueous electrolyte rechargeable batteries which allows production of batteries having improved load characteristics with stable quality, and also allows production of batteries having high capacity. Also provided are a cathode for nonaqueous electrolyte rechargeable batteries and a nonaqueous electrolyte rechargeable battery. The cathode active material includes secondary particles each composed of a plurality of primary particles, and/or single crystal grains, and has a specific surface area of not smaller than 20 m2/g and smaller than 0.50 m2/g, wherein average number A represented by formula (1) is not less than 1 and not more than 10:
A=(m+p)/(m+s)
(m: the number of single crystal grains; p: the number of primary particles composing the secondary particles; s: the number of secondary particles).

主权项

1. A cathode active material for nonaqueous electrolyte rechargeable batteries comprising
single crystal grains; and secondary particles each composed of a plurality of primary particles, said cathode active material being represented by the following formula:
LixCo1−yMyO2+z wherein M stands for one or more elements selected from the group consisting of Na, Mg, Ca, Y, rare earth elements, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ni, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, N, P, S, F, and Cl, with Ti and/or Mg being essential; x is 0.9≦x≦1.1, y is 0A=(m+p)/(m+s)  (1) wherein m is the number of single crystal grains, p is the number of primary particles composing the secondary particles, and s is the number of secondary particles, wherein the particle diameter of said secondary particles is not smaller than 1 μm and not larger than 70 μm.