SOLID ELECTROLYTE
A solid electrolyte contains Li, P, S, halogen, and M elements (M represents at least one of silicon (Si), tin (Sn), antimony (Sb), germanium (Ge), and boron (B)), and has a crystalline phase with an argyrodite-type crystal structure. A molar ratio S/(P+M) of the S to the total of the P and M elements satisfies 3.5<S/(P+M)<4.2. A molar ratio M/P of the M element to the P satisfies 0<M/P<1. A molar ratio X/(P+M) of the halogen (X) element to the total of the P and M elements satisfies 0.7<X/(P+M)<3.0.
1 . A solid electrolyte comprising a lithium (Li) element, a phosphorus (P) element, a sulfur (S) element, a halogen (X) element, and an M element (M represents at least one of silicon (Si), tin (Sn), antimony (Sb), germanium (Ge), and boron (B)),
wherein a molar ratio S/(P+M) of the sulfur (S) element to a total of the phosphorus (P) element and the M element satisfies 3.5<S/(P+M)<4.2,
a molar ratio M/P of the M element to the phosphorus (P) element satisfies 0<M/P<1, and
the solid electrolyte has a crystalline phase with an argyrodite-type crystal structure.
2 . The solid electrolyte according to claim 1 , wherein, a ratio I a /I a of I a to I 0 is 1.6 or less,
wherein I a represents an intensity of a peak A observed at a position 2θ=21.3°±0.3° in an X-ray diffraction pattern measured by an X-ray diffractometer (XRD) using CuKα1 radiation, and
I 0 represents a background of the X-ray diffraction pattern.
3 . The solid electrolyte according to wherein, a ratio I b /I 0 of I b to I 0 is 2.5 or less,
wherein I b represents an intensity of a peak B observed at a position 2θ=19.4°±0.3° in an X-ray diffraction pattern measured by an X-ray diffractometer (XRD) using CuKα1 radiation, and
I 0 represents a background of the X-ray diffraction pattern.
4 . The solid electrolyte according to claim 1 , wherein a molar ratio X/(P+M) of the halogen (X) element to a total of the phosphorus (P) element and the M element satisfies 0.7<X/(P+M)<3.0.
5 . The solid electrolyte according to claim 1 , wherein the solid electrolyte has a composition represented by Li w P 1-x M x S y X z
wherein w represents a number of 4.5 to 5.5,
x represents a number of 0.05 to 0.45,
y represents a number of 3.5 to 4.2, and
z represents a number of more than 1.0 and 3.0 or less.
6 . The solid electrolyte according to claim 1 , wherein the halogen (X) element includes a bromine (Br) element.
7 . The solid electrolyte according to claim 1 , wherein the halogen (X) includes a bromine (Br) element and a chlorine (Cl) element.
8 . The solid electrolyte according to claim 1 , wherein a proportion of the sulfur (S) element to all elements is 40 mol % or less.
9 . An electrode material mixture comprising the solid electrolyte according to claim 1 and an active material.
10 . A solid electrolyte layer comprising the solid electrolyte according claim 1 .
11 . A battery comprising 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 contains the solid electrolyte according to claim 1 .