Sulfide solid electrolyte and battery
A novel sulfide solid electrolyte containing Li, P, S, and a halogen, which can be used as a solid electrolyte for a lithium secondary battery or the like, and is able to suppress the generation of a hydrogen sulfide gas even when exposed to moisture in the atmosphere. The sulfide solid electrolyte comprises a crystal phase or a compound having an argyrodite-type structure and containing Li, P, S, and a halogen; and a compound composed of Li, Cl, and Br and having a peak at each position of 2θ=29.1°±0.5° and 33.7°±0.5° in an X-ray diffraction pattern.
1. A sulfide solid electrolyte comprising
a compound, referred to as “component A”, having an argyrodite-type structure and containing a lithium (Li) element, a phosphorus (P) element, a sulfur (S) element, and a halogen (X) element, and
a compound, referred to as, “component B”, composed of a lithium (Li) element, a chlorine (Cl) element, and a bromine (Br) element and having a peak at each position of 2θ=29.1°±0.5° and 33.7°±0.5° in an X-ray diffraction pattern measured by an X-ray diffraction apparatus (XRD) using CuKα1 rays,
wherein, when an intensity of a peak located at 2θ=30.2°±0.5° is defined as IA and an intensity of a peak located at 2θ=29.1°±0.5° is defined as IB, in an X-ray diffraction pattern measured by the X-ray diffraction apparatus (XRD) using CuKα1 rays, a ratio, Ia/IB of IA to IB satisfies 0<IA/IB≤3.5.
2. The sulfide solid electrolyte according to claim 1 , wherein the component B has a peak at each position of 2θ=49.0°±0.5°, 58.0°±0.5°, and 60.0°±0.5° in an X-ray diffraction pattern measured by the X-ray diffraction apparatus (XRD) using CuKα1 rays.
3. The sulfide solid electrolyte according to claim 1 , wherein, when a particle diameter of the compound A is defined as D 50A and a particle diameter of the compound B is defined as D 50B , and D 50A and D 50B satisfy 1<(D 50A +D 50B )/D 50A .
4. The sulfide solid electrolyte according to claim 1 , wherein the content of the compound B in the sulfide solid electrolyte is 1% by mass or more and 50% by mass or less.
5. The sulfide solid electrolyte according to claim 1 , wherein a ratio, (Cl+Br)/P, of a total content in mols of a chlorine (Cl) element and a bromine (Br) element to the content in mols of a phosphorus (P) element satisfies 1.6<(Cl+Br)/P<20.0.
6. A battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the battery comprises the sulfide solid electrolyte according to claim 1 .
7. The sulfide solid electrolyte according to claim 2 , wherein, when a particle diameter of the compound A is defined as D 50A and a particle diameter of the compound B is defined as D 50B , and D 50A and D 50B satisfy 1<(D 50A +D 50B )/D 50A .
8. The sulfide solid electrolyte according to claim 2 , wherein the content of the compound B in the sulfide solid electrolyte is 1% by mass or more and 50% by mass or less.
9. The sulfide solid electrolyte according to claim 2 , wherein a ratio, (Cl+Br)/P, of a total content in mols of a chlorine (Cl) element and a bromine (Br) element to the content in mols of a phosphorus (P) element satisfies 1.6<(Cl+Br)/P<20.0.
10. A battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the battery comprises the sulfide solid electrolyte according to claim 2 .
11. A battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the battery comprises the sulfide solid electrolyte according to claim 3 .
12. A battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the battery comprises the sulfide solid electrolyte according to claim 4 .
13. A battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the battery comprises the sulfide solid electrolyte according to claim 5 .