All solid-state secondary battery, inorganic solid electrolyte particles, solid electrolyte composition, electrode sheet for battery, and method for manufacturing all solid-state secondary battery
Provided are an all solid-state secondary battery capable of exhibiting an improved ion-conducting property regardless of troublesome manufacturing steps or special materials, inorganic solid electrolyte particles, a solid electrolyte composition, an electrode sheet for a battery, and a method for manufacturing an all solid-state secondary battery. An all solid-state secondary battery comprising: a positive electrode active material layer; a negative electrode active material layer; and an inorganic solid electrolyte layer between the positive and negative electrode active material layers, in which inorganic solid electrolyte particles satisfying all of the following data A are included in at least any layer of the positive electrode active material layer, the negative electrode active material layer, or the inorganic solid electrolyte layer: <data A> a boundary length of a projected particle of the inorganic solid electrolyte particle is represented by L; a cross-sectional area of the projected particle of the inorganic solid electrolyte particle is represented by A; an unevenness coefficient FU represented by Expression (1) below is in a range of 0.85 or more and 1 or less; FU =4π A/L 2 (1).
1. An all solid-state secondary battery comprising:
a positive electrode active material layer,
a negative electrode active material layer; and
an inorganic solid electrolyte layer between the positive and negative electrode active material layers,
wherein inorganic solid electrolyte particles whose primary particles satisfying all of the following data A are included in at least any layer of the positive electrode active material layer, the negative electrode active material layer, or the inorganic solid electrolyte layer:
<data A>
a perimeter of a projected particle of the inorganic solid electrolyte particle is represented by L;
a cross-sectional area of the projected particle of the inorganic solid electrolyte particle is represented by A;
an unevenness coefficient FU represented by Expression (1) below is in a range of 0.85 or more and 1 or less;
FU= 4π A/L 2 (1).
2. The all solid-state secondary battery according to claim 1 ,
wherein an average particle diameter of the inorganic solid electrolyte particles is 1 μm or more and 10 μm or less.
3. The all solid-state secondary battery according to claim 1 ,
wherein D90 of the inorganic solid electrolyte particles is 2 μm or more and 20 μm or less.
4. The all solid-state secondary battery according to claim 1 ,
wherein a flatness ratio that is evaluated using Feret's diameter of the inorganic solid electrolyte particles is 1.2 or higher and 1.76 or lower.
5. The all solid-state secondary battery according to claim 1 ,
wherein thicknesses of the positive electrode active material layer, the negative electrode active material layer, and the inorganic solid electrolyte layer are respectively 1 μm or more and 1,000 μm or less.
6. The all solid-state secondary battery according to claim 1 ,
wherein at least one layer of the positive electrode active material layer, the negative electrode active material layer, or the inorganic solid electrolyte layer includes a binder.
7. The all solid-state secondary battery according to claim 1 ,
wherein the inorganic solid electrolyte particles are oxide-based inorganic solid electrolyte particles.
8. The all solid-state secondary battery according to claim 7 ,
wherein the oxide-based inorganic solid electrolyte particles are selected from compounds of the following formulae:
Li xa La ya TiO 3
xa=0.3 to 0.7, ya=0.3 to 0.7
Li 7 La 3 Zr 2 O 12
Li 3.5 Zn 0.25 GeO 4
LiTi 2 P 3 O 12
Li 1+xb+yb (Al, Ga) xb (Ti, Ge) 2−xb Si yb P 3−yb O 12
0≤xb≤1, 0≤yb≤1
Li 3 PO 4
LiPON
LiPOD
D is at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, or Au
LiAON
A is at least one selected from Si, B, Ge, Al, C, or Ga.
9. The all solid-state secondary battery according to claim 1 ,
wherein the inorganic solid electrolyte particles are sulfide-based inorganic solid electrolyte particles.
10. The all solid-state secondary battery according to claim 9 ,
wherein, when the sulfide-based inorganic solid electrolyte particles are prepared by means of stirring and crushing in a crushing medium including crushing particles in a mixing tank in a crusher,
an average particle diameter of the crushing particles is set to 1,000 times or more and 10,000 times or less the average particle diameter of target inorganic solid electrolyte particles, and a density of the crushing particles is set to 0.9 g/cm 3 or more and 2.4 g/cm 3 or less.
11. The all solid-state secondary battery according to claim 10 ,
wherein the crushing particles include at least one selected from thermosetting plastic particles, thermoplastic plastic particles, or rubber particles.
12. The all solid-state secondary battery according to claim 1 ,
wherein, when the inorganic solid electrolyte particles are prepared by means of stirring and crushing in a crushing medium including crushing particles in a mixing tank in a crusher,
an average particle diameter of the crushing particles is set to 100 times or more and 1,500 times or less the average particle diameter of target inorganic solid electrolyte particles, and a filling percentage of the crushing particles in the mixing tank is set to be higher than 60% and 74% or lower according to a definition of Expression (2) below:
filling percentage α=Σ Z/V 0 ×100 (2)
V 0 : an inner volume of the mixing tank
ΣZ: a sum of volumes of the crushing particles filling the mixing tank.
13. The all solid-state secondary battery according to claim 12 ,
wherein the crushing particles include at least one material selected from agate, alumina, zirconia, stainless steel, chromium steel, tungsten carbide, or silicon nitride.