Sulfide solid electrolyte material, positive electrode material, and battery
A sulfide solid electrolyte material includes a sulfide phase containing a sulfide material and an oxide phase containing an oxide formed by oxidation of the sulfide material. The oxide phase is located on a surface of the sulfide phase. The sulfide solid electrolyte material satisfies conditions: 1.28≤x≤4.06 and x/y≥2.60, where x denotes the oxygen-to-sulfur elemental ratio measured by XPS depth profiling at the outermost surface of the oxide phase; and y denotes the oxygen-to-sulfur elemental ratio measured by XPS depth profiling at a position 32 nm, estimated from the SiO 2 sputtering rate, away from the outermost surface of the oxide phase.
1. A sulfide solid electrolyte material comprising:
a sulfide phase containing a sulfide material; and
an oxide phase containing an oxide formed by oxidation of the sulfide material, wherein
the oxide phase is located on a surface of the sulfide phase; and
the sulfide solid electrolyte material satisfies conditions:
1.28≤ x≤ 4.06, and
x/y≥ 2.60, where
x denotes an oxygen-to-sulfur elemental ratio measured by X-ray photoelectron spectroscopy depth profiling at the outermost surface of the oxide phase; and
y denotes an oxygen-to-sulfur elemental ratio measured by XPS depth profiling at a position 32 nm, estimated from an SiO 2 sputtering rate, away from the outermost surface of the oxide phase.
2. The sulfide solid electrolyte material according to claim 1 , satisfying a condition: 2.71≤x≤4.06.
3. The sulfide solid electrolyte material according to claim 1 , wherein the sulfide material is Li 2 S—P 2 S 5 .
4. A battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte layer disposed between the positive electrode and the negative electrode, wherein
at least one of the positive electrode, the negative electrode, and the electrolyte layer contains a sulfide solid electrolyte material;
the sulfide solid electrolyte material includes a sulfide phase containing a sulfide material and an oxide phase containing an oxide formed by oxidation of the sulfide material;
the oxide phase is located on a surface of the sulfide phase; and
the sulfide solid electrolyte material satisfies conditions:
1.28≤ x≤ 4.06, and
x/y ≥2.60, where
x denotes an oxygen-to-sulfur elemental ratio measured by XPS depth profiling at the outermost surface of the oxide phase; and
y denotes an oxygen-to-sulfur elemental ratio measured by XPS depth profiling at a position 32 nm, estimated from an SiO 2 sputtering rate, away from the outermost surface of the oxide phase.
5. The battery according to claim 4 , wherein
the positive electrode contains the sulfide solid electrolyte material and a positive electrode active material; or
the negative electrode contains the sulfide solid electrolyte material and a negative electrode active material.
6. The battery according to claim 5 , wherein
the positive electrode contains the sulfide solid electrolyte material and a positive electrode active material; and
the positive electrode active material is Li(NiCoAl)O 2 .
7. The battery according to claim 5 , wherein
the positive electrode contains the sulfide solid electrolyte material and a positive electrode active material; and
the positive electrode active material is LiCoO 2 .
8. The battery according to claim 5 , wherein
the positive electrode contains the sulfide solid electrolyte material, a positive electrode active material, and a conductive assistant.
9. The battery according to claim 8 , wherein
the conductive assistant is acetylene black.
10. A positive electrode material comprising:
a sulfide solid electrolyte material;
a positive electrode active material; and
a conductive assistant, wherein
the sulfide solid electrolyte material includes a sulfide phase containing a sulfide material and an oxide phase containing an oxide formed by oxidation of the sulfide material;
the oxide phase is located on a surface of the sulfide phase; and
the sulfide solid electrolyte material satisfies conditions:
1.28≤ x≤ 4.06, and
x/y ≥2.60, where
x denotes an oxygen-to-sulfur elemental ratio measured by XPS depth profiling at the outermost surface of the oxide phase; and
y denotes an oxygen-to-sulfur elemental ratio measured by XPS depth profiling at a position 32 nm, estimated from an SiO 2 sputtering rate, away from the outermost surface of the oxide phase.
11. The positive electrode material according to claim 10 , wherein
the conductive assistant is acetylene black.