Transition metal composite hydroxide particles and production method thereof, cathode active material for non-aqueous electrolyte rechargeable battery and production method thereof, and nonaqueous electrolyte rechargeable battery
Provided is a cathode active material that can simultaneously improve the capacity characteristics, output characteristics, and cycling characteristics of a rechargeable battery when used as cathode material for a non-aqueous electrolyte rechargeable battery. After performing nucleation by controlling an aqueous solution for nucleation that includes a metal compound that includes at least a transition metal and an ammonium ion donor so that the pH value becomes 12.0 to 14.0 (nucleation process), nuclei are caused to grow by controlling aqueous solution for particle growth that includes the nuclei so that the pH value is less than in the nucleation process and is 10.5 to 12.0 (particle growth process). When doing this, the reaction atmosphere in the nucleation process and at the beginning of the particle growth process is a non-oxidizing atmosphere, and in the particle growth process, atmosphere control by which the reaction atmosphere is switched from this non-oxidizing atmosphere to an oxidizing atmosphere, and is then switched again to a non-oxidizing atmosphere is performed at least one time. Cathode active material is obtained with the composite hydroxide particles that are obtained by this kind of crystallization reaction as a precursor.
1. Cathode active material for a non-aqueous electrolyte rechargeable battery comprising secondary particles that are formed by an aggregation of plural primary particles,
the cathode active material comprising layered hexagonal crystal lithium nickel manganese composite oxide particles that are expressed by the general expression (B): Li 1+u Ni x Mn y Co z M t O 2 , where −0.05≤u≤0.50, x+y+z+t=1, 0.3≤x≤0.95, 0.05≤y≤0.55, 0≤z≤0.4, 0≤t≤0.1, and M is one or more additional element that is selected from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W,
the secondary particles having a center section comprising the aggregation of plural primary particles, the center section having a solid structure or hollow structure provided with a hollow part at its inside, an outer-shell section comprising the aggregation of plural primary particles and located on the outside of the center section, at least a hollow section located between the center section and the outer-shell section where there are no primary particles, and a connecting section electrically connecting between the outer-shell section and the center section;
the average value of the ratio of the center section outer diameter with respect to the particle size of the secondary particles being 30% to 80%, and the average value of the ratio of the outer-shell section radial direction thickness with respect to the particle size being 5% to 25%; and
the secondary particles having an average particle size of 1 μm to 15 μm, and an index [(d90−d10)/average particle size] that indicates the extent of the particle size distribution of 0.7 or less.
2. Cathode active material for a non-aqueous electrolyte rechargeable battery comprising secondary particles that are formed by an aggregation of plural primary particles,
the cathode active material comprising layered hexagonal crystal lithium nickel manganese composite oxide particles that are expressed by the general expression (B): Li 1+u Ni x Mn y Co z M t O 2 , where −0.05≤u≤0.50, x+y+z+t=1, 0.3≤x≤0.95, 0.05≤y≤0.55, 0≤z≤0.4, 0≤t≤0.1, and M is one or more additional element that is selected from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W,
the secondary particles comprising a center section comprising the aggregation of plural primary particles, the center section having a solid structure or hollow structure provided with a hollow part at its inside, an outer-shell section comprising the aggregation of plural primary particles and located on the outside of the center section, a hollow section located between the center section, and outer-shell section where there are no primary particles, at least one inner-shell section comprising the aggregation of plural primary particles and located between the center section and the outer-shell section, the at least one inner-shell section separated from the center section and the outer-shell section by the hollow section, and a connecting section electrically connecting among the outer-shell section, the inner-shell section and the center section; and
the secondary particles having an average particle size of 1 μm to 15 μm, and an index [(d90−d10)/average particle size] that indicates the extent of the particle size distribution of 0.7 or less.
3. The cathode active material for a non-aqueous electrolyte rechargeable battery according to claim 2 , wherein the average value of the ratio of the center section outer diameter with respect to the particle size of the secondary particles is 20% to 70%, and the average value of the ratio of the total thickness in the radial direction of the inner-shell section and the outer shell section with respect to the particles size of the secondary particles is 10% to 35%.
4. The cathode active material for a non-aqueous electrolyte rechargeable battery according to claim 1 , wherein the specific surface area is 0.7 m 2 /g to 3.0 m 2 /g.
5. A non-aqueous electrolyte rechargeable battery comprising a cathode, an anode, a separator and a non-aqueous electrolyte, wherein the cathode active material for a non-aqueous electrolyte rechargeable battery according to claim 1 is used as cathode material for the cathode.