Method of preparing an oxide-based solid electrolyte by a hydrothermal reaction
View Patent ↗A method of preparing an oxide-based solid electrolyte includes preparing a precursor solution which includes a lanthanide complex and a metal complex; preparing an intermediate by a hydrothermal reaction that is performed on the precursor solution; adding a lithium compound and a dopant precursor to the intermediate to prepare a mixture; and crystallizing the mixture. The mixture is crystallized by preparing a first oxide-based solid electrolyte by performing a first crystallization process on the mixture; and preparing a second oxide-based solid electrolyte by performing a second crystallization process on the first oxide-based solid electrolyte, wherein the second oxide-based solid electrolyte has a stoichiometric composition that is the same as that of the first oxide-based solid electrolyte, but that has a different crystal structure.
1. A method of preparing an oxide-based solid electrolyte, the method comprising:
preparing a precursor solution which includes a lanthanide complex and a metal complex;
preparing an intermediate by a hydrothermal reaction that is performed on the precursor solution;
adding a lithium compound and a dopant precursor to the intermediate to prepare a mixture; and
crystallizing the mixture by:
preparing a first oxide-based solid electrolyte by performing a first crystallization process on the mixture; and
preparing a second oxide-based solid electrolyte by performing a second crystallization process on the first oxide-based solid electrolyte,
wherein the second oxide-based solid electrolyte has a stoichiometric composition that is the same as that of the first oxide-based solid electrolyte, but that has a different crystal structure.
2. The method of claim 1 , wherein the hydrothermal reaction of the precursor solution is performed in a temperature range of 120° C. to 240° C. for 2 hours to 48 hours.
3. The method of claim 1 , wherein preparing the precursor solution comprises:
preparing a first precursor solution by adding the lanthanide complex and the metal complex to an acidic aqueous solution; and
forming precursor precipitates by adding a mineralizer to the first precursor solution.
4. The method of claim 1 , wherein the second oxide-based solid electrolyte has a higher ionic conductivity than the first oxide-based solid electrolyte.
5. The method of claim 1 , wherein the first oxide-based solid electrolyte has a tetragonal phase, and
the second oxide-based solid electrolyte has a cubic phase.
6. The method of claim 1 , wherein the second oxide-based solid electrolyte has a chemical formula of Li x-y La 3 M 2 O 12-y ,
where x is 5 or 7, y is 0.3 to 0.7, and M is any one selected from the group consisting of tantalum, niobium, zirconium, and a combination thereof.
7. The method of claim 1 , wherein the first crystallization process is performed in a temperature range of 700° C. to 900° C. for 6 hours to 12 hours.
8. The method of claim 1 , wherein the second crystallization process is performed in a temperature range of 1000° C. to 1100° C. for 6 hours to 12 hours.
9. The method of claim 1 , wherein the dopant precursor comprises at least one element selected from the group consisting of aluminum, germanium, silicon, gallium, indium, tin, and antimony.