Lithium metal composite oxide powder, positive electrode active material for solid secondary batteries, positive electrode for solid secondary batteries and solid secondary batteries

Abstract

To provide lithium metal composite oxide powder which can obtain a solid secondary battery with a low increase in the resistance following charging / discharging, a cathode active material for solid secondary battery, a cathode for solid-state battery and a solid secondary battery.SOLUTION: There is provided lithium metal composite oxide powder used for a solid secondary battery which has a layer structure and includes at least Li, Mn and an element M1. When the equivalent circle diameters (μm) whose accumulation ratios from the small particle side become 50%, 90% in the cumulative grain size distribution of the volume reference of the projection area equivalent circle diameter of the lithium metal composite oxide powder measured by the static image analysis are CD50, CD90, the number average envelope degree of particles satisfying the range between the CD50 and the CD90 is between 0.860 and 0.980, and the composition formula (1) is satisfied.SELECTED DRAWING: None

Claims

1. A lithium metal composite oxide powder having a layered structure and containing at least Li, Mn, and element M1, used in solid-state secondary batteries, In the volume-based cumulative particle size distribution of the lithium metal composite oxide powder, measured by static image analysis, when the equivalent circle diameters (μm) at which the cumulative proportion from the smallest particles is 50% and 90% are defined as CD50 and CD90, respectively, The number-mean envelope of particles satisfying the range of CD50 or more and CD90 or less is 0.860 or more and 0.980 or less. The following composition formula (1) is satisfied, In the cumulative particle size distribution, when CD10 is defined as the equivalent circle diameter (μm) at which the cumulative proportion from the small particle side is 10%, then CD10 is 3.0 μm or more and 7.0 μm or less. The aforementioned solid secondary battery includes a solid electrolyte with an average particle size of 1 μm or less. Lithium metal composite oxide powder. aLi ２ MnO ３ ・(1-a) LiM1O ２ ... (1) (In formula (1), 0.1 < a < 1, and M1 is one or more elements selected from the group consisting of Ni, Co, Mn, Fe, Cu, Ti, V, Na, Mg, Ca, Sr, Ba, B, Al, Si, P, W, Mo, Nb, Zn, Sn, Zr, Cr, Ga, Ge, Pd, Ag, Cd, In, and V.)

2. The lithium metal composite oxide powder according to claim 1, wherein, in the cumulative particle size distribution, when the equivalent circle diameter (μm) at which the cumulative proportion from the small particle side is 10% is defined as CD10, the number-average envelope of particles satisfying the range of CD10 or more and CD50 or less is 0.950 or more and less than 1.

3. The lithium metal composite oxide powder according to claim 1 or 2, wherein the CD90 is greater than 7.0 μm and less than or equal to 20.0 μm.

4. The lithium metal composite oxide powder according to claim 2 or 3, wherein the CD10 is 3.0 μm or more and 7.0 μm or less.

5. BET specific surface area is 0.3 m² ２ / g or more 2.0m ２ A lithium metal composite oxide powder according to any one of claims 1 to 4, wherein the amount is less than or equal to / g.

6. The lithium metal composite oxide powder according to any one of claims 1 to 5, wherein the element M1 is Ni, and the proportion of Ni in the total amount of element M1 is 20 mol% or more.

7. A positive electrode active material for a solid secondary battery, comprising the lithium metal composite oxide powder described in any one of claims 1 to 6.

8. A positive electrode for a solid secondary battery comprising the positive electrode active material for a solid secondary battery as described in claim 7.

9. A solid-state secondary battery comprising a positive electrode for a solid-state secondary battery as described in claim 8.

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