Positive electrode material and battery
View Patent ↗Provided is a positive electrode material including a first solid electrolyte, a positive electrode active material, and a coating material at least partially coating a surface of the positive electrode active material. The first solid electrolyte is represented by the following compositional formula (1): Li a M b X c . In the compositional formula (1), a, b, and c are positive real numbers and satisfy a mathematical expression: a+b<c; M is at least one selected from the group consisting of metallic elements excluding Li and metalloid elements; and X is at least one selected from the group consisting of F, Cl, Br, and I. The coating material includes an oxoacid salt of a non-metal or metalloid cation.
1 . A positive electrode material comprising:
a first solid electrolyte;
a positive electrode active material; and
a coating material at least partially coating a surface of the positive electrode active material, wherein
the first solid electrolyte is represented by a following compositional formula (1):
Li a M b X c Formula (1),
in the compositional formula (1):
a, b, and c are positive real numbers and satisfy a mathematical expression: a+b<c;
M is at least one selected from the group consisting of metallic elements excluding Li and metalloid elements; and
X is at least one selected from the group consisting of F, Cl, Br, and I,
the coating material includes an oxoacid salt of a non-metal or metalloid cation,
the oxoacid salt includes lithium silicophosphate, and
a coverage rate as a proportion of a coated surface area of the positive electrode active material coated with the coating material to a whole surface area of the positive electrode active material is 10% or more and is 90% or less.
2 . The positive electrode material according to claim 1 , wherein the surface of the positive electrode active material is partially covered by the coating material.
3 . The positive electrode material according to claim 1 , wherein a mass proportion of the oxoacid salt to the positive electrode active material is 0.1 mass % or more and is 2.3 mass % or less.
4 . The positive electrode material according to claim 3 , wherein the mass proportion of the oxoacid salt to the positive electrode active material is 0.1 mass % or more and is 2.0 mass % or less.
5 . The positive electrode material according to claim 1 , wherein a mass proportion of the oxoacid salt to the positive electrode active material is 0.25 mass % or more and is 1.14 mass % or less.
6 . The positive electrode material according to claim 1 , wherein the M includes Y.
7 . The positive electrode material according to claim 1 , wherein the X includes at least one selected from the group consisting of F, Cl, and Br.
8 . The positive electrode material according to claim 1 , wherein the X includes at least two selected from the group consisting of F, Cl, and Br.
9 . The positive electrode material according to claim 1 , wherein the X includes Cl and Br.
10 . The positive electrode material according to claim 1 , wherein the positive electrode active material includes a lithium-containing transition metal oxide.
11 . The positive electrode material according to claim 1 , wherein the X includes at least one selected from the group consisting of F and I.
12 . The positive electrode material according to claim 1 , wherein the X includes at least one selected from the group consisting of F and I and at least one selected from the group consisting of Br and Cl.
13 . The positive electrode material according to claim 1 , wherein the coating material has a thickness of 1 nm to 100 nm on the surface of the positive electrode active material, and serves to suppress electron transfer between the positive electrode active material and the first solid electrolyte.
14 . The positive electrode material according to claim 1 , wherein the coating material is formed in situ by reacting a lithium source, a silicon source, and a phosphorus source on the surface of the positive electrode active material during a heat treatment.
15 . A battery comprising:
a positive electrode including the positive electrode material according to claim 1 ;
a negative electrode; and
an electrolyte layer disposed between the positive electrode and the negative electrode.
16 . The battery according to claim 15 , wherein the electrolyte layer includes a sulfide solid electrolyte.