Solid solution, electrode active material, electrode and secondary battery
An object is to provide an electrode active material having a novel structure, said electrode active material enabling Li 2 S to be used as an electrode. The problem is solved by a solid solution with an antifluorite crystal structure comprising Li, Cu, and S as main constituents.
1 . A solid solution with an antifluorite crystal structure comprising Li, Cu, and S as main constituents,
wherein the solid solution is represented by the following formula (1):
Li
4
-
x
-
y
-
z
Cu
x
-
y
M
y
S
2
-
z
A
z
(
1
)
(where M is selected from Mg, Ca, Ni, Zn, Fe, Co, Sn, Pb, or Mn, A is a monovalent anion, x is 0.1 or more and 2.0 or less, y is more than 0 and less than 1.0, z is more than 0 and 1.0 or less, and x>y).
2 . The solid solution according to claim 1 , wherein x is in a range of 0.5 to 1.0 in the formula (1).
3 . The solid solution according to claim 1 , wherein y is more than 0 and less than 0.5 in the formula (1).
4 . The solid solution according to claim 1 , wherein z is more than 0 and 0.5 or less in the formula (1).
5 . The solid solution according to claim 1 , wherein the A is selected from F, Cl, Br, or I.
6 . The solid solution according to claim 1 , wherein a lattice constant of an a-axis of the solid solution is in a range of 5.60 Å to 5.80 Å.
7 . An electrode active material comprising the solid solution according to claim 1 .
8 . The electrode active material according to claim 7 , further comprising a solid electrolyte.
9 . An electrode comprising the solid solution according to claim 1 .
10 . A secondary battery comprising the electrode according to claim 9 .
11 . The secondary battery according to claim 10 , wherein the secondary battery is an all-solid-state secondary battery.
12 . A mixed body of the solid solution according to claim 1 , and at least one solid electrolyte selected from Li 3 PS 4 , Li 7 P 3 S 11 , Li 2 S—P 2 S 5 —LiI, Li 2 S—P 2 S 5 —LiI—LiBr, Li 2 S—P 2 S 5 —Li 2 O, Li 2 S—P 2 S 5 —Li 2 O—LiI, and Li 2 S—P 2 S 5 —GeS 2 .
13 . The mixed body according to claim 12 , wherein the weight ratio of solid solution to solid electrolyte ranges from 1:1 to 7:3 (solid solution: solid electrolyte).
14 . The mixed body according to claim 12 , wherein the mixed body is in the form of composite.
15 . An electrode active material comprising the mixed body according to claim 12 .
16 . An electrode comprising the electrode active material according to claim 7 .
17 . An electrode composite wherein the electrode according to claim 16 is combined with a current collector.
18 . A secondary battery comprising the electrode composite according to claim 17 .