Electrolyte material and methods of forming
A solid electrolyte material can include a halide-based material having a crystalline structure including a disorder. In an embodiment, the solid electrolyte material can include a crystalline structure include stacking faults. In another embodiment, the solid electrolyte material can include a crystalline phase including a crystalline structure represented by a space group of the hexagonal crystal system or a space group of a rhombohedral lattice system. In another embodiment, the solid electrolyte material can include a crystalline phase including a crystalline structure represented by a monoclinic space group and a unit cell containing a reduced number of halogen atoms.
1. A solid electrolyte material, comprising:
M 3−z (Me k+ ) f X 3−z+k*f , wherein −3≤z<3; 2≤k≤6; 0≤f≤1; M comprises an alkali metal element; Me comprises a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X comprises a halogen;
a crystalline structure including stacking faults of at least 20% and an average diffraction crystallite size of at least 25 nm.
2. The solid electrolyte material of claim 1 , wherein the crystalline structure is represented by C2/m space group.
3. The solid electrolyte material of claim 1 , wherein the crystalline structure comprises at least 50% stacking faults.
4. The solid electrolyte material of claim 1 , wherein X-ray diffraction pattern measured with Cu K-alpha radiation includes an absence of a peak between 16° and 25° 2-theta.
5. The solid electrolyte material of claim 1 , wherein M comprises at least one of Li or Na.
6. The solid electrolyte material of claim 1 , wherein Me comprises a rare earth element, Zr, Sn, or any combination thereof.
7. The solid electrolyte material of claim 1 , wherein Me comprises Y.
8. The solid electrolyte material of claim 1 , wherein X comprises Cl, Br, or a combination thereof.
9. The solid electrolyte material of claim 1 , wherein the solid electrolyte material consists of Li, Y, Cl, and Br.
10. The solid electrolyte material of claim 1 , comprising a crystalline phase comprising a crystalline structure represented by P-3m1 or Pnma space group.
11. The solid electrolyte material of claim 1 , wherein the crystalline structure comprises at least 70% stacking fault.
12. A solid electrolyte material, comprising
M 3−z (Me k+ ) f X 3−z+k*f , wherein −3≤z<3; 2≤k≤6; 0≤f≤1; M comprises an alkali metal element; Me comprises a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X comprises a halogen;
a crystalline structure represented by a rhombohedral space group or a hexagonal space group and including an average diffraction crystallite size of at least 25 nm.
13. The solid electrolyte material of claim 12 , comprising a crystalline phase comprising a crystalline structure represented by R-3m space group.
14. The solid electrolyte material of claim 12 , comprising a crystalline phase comprising a crystalline structure represented by P6 3 /mcm or P6 3 /mmc space group.
15. The solid electrolyte material of claim 12 , wherein M comprises Li, Na, or a combination thereof, wherein Me comprises Y, Ce, Gd, Er, Zr, La, Yb, In, Mg, Zn, Sn or any combination thereof, and wherein X comprises at least one of Br and Cl.
16. The solid electrolyte material of claim 12 , wherein the crystalline structure comprises stacking faults of at least 90% and an average diffraction crystallite size of at least 30 nm and at most 500 nm.
17. The solid electrolyte material of claim 12 , wherein the crystalline structure comprises:
a layered atomic arrangement; and
at least one of the following:
atomically disordered vacancy and Me atoms;
disordered X1 and X2 atoms, wherein X1 and X2 represent two different halogen atoms;
disordered vacancy sites and M atoms;
disordered M and Me atoms;
disordered M, Me, and vacancy atoms; or
any combination thereof.
18. A solid electrolyte material, comprising:
M 3−z (Me k+ ) f X 3−z+k*f , wherein −3≤z<3; 2≤k≤6; 0≤f≤1; M comprises an alkali metal element; Me comprises a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X comprises a halogen;
a crystalline structure represented by a monoclinic space group having a unit cell containing between 3 and 5 halide atoms and including an average diffraction crystallite size of at least 25 nm.
19. The solid electrolyte material of claim 18 , comprising a crystalline phase comprising a crystalline structure represented by C2/m space group.
20. The solid electrolyte material of claim 18 , comprising a layered atomic arrangement; and wherein the average diffraction crystallite size is at least 35 nm.