Solid electrolyte, method for producing solid electrolyte, secondary battery, and electronic apparatus
A lithium battery as a secondary battery includes a positive electrode composite material containing a solid electrolyte and a positive electrode active material containing lithium, a negative electrode as an electrode provided at one face of the positive electrode composite material, and a current collector provided at another face of the positive electrode composite material, wherein the solid electrolyte is a garnet-type fluorine-containing lithium composite metal oxide that is represented by the following compositional formula (1) or (2) and that conducts lithium. (Li 7−3x Ga x )(La 3−y Nd y )Zr 2 O 12−z F z (1) (Li 7−3x+y Ga x )(La 3−y Ca y )Zr 2 O 12−z F z (2) Provided that 0.1≤x≤1.0, 0<y≤0.2, and 0<z≤1.0.
1. A garnet-type solid electrolyte that is represented by the following compositional formula (1) or (2) and that conducts lithium:
(Li 7−3x Ga x )(La 3−y Nd y )Zr 2 O 12−z F z (1)
(Li 7−3x+y Ga x )(La 3−y Ca y )Zr 2 O 12−z F z (2)
provided that 0.1≤x≤1.0, 0<y≤0.2, and 0<z≤1.0.
2. A method for producing a solid electrolyte being a method for producing a garnet-type solid electrolyte that is represented by the following compositional formula (1) or (2) and that conducts lithium, the method comprising:
forming a first mixture by mixing raw material solutions containing elements shown in the compositional formula (1) or (2);
forming a calcined body by subjecting the first mixture to a first heating treatment;
forming a second mixture by mixing the calcined body with lithium fluoride; and
performing main firing by subjecting the second mixture to a second heating treatment, wherein
a mixing amount of the lithium fluoride is an amount configured to substitute 1 atom or less of oxygen with fluorine:
(Li 7−3x Ga x )(La 3−y Nd y )Zr 2 O 12−z F z (1)
(Li 7−3x+y Ga x )(La 3−y Ca y )Zr 2 O 12−z F z (2)
provided that 0.1≤x≤1.0, 0<y≤0.2, and 0<z≤1.0.
3. A method for producing a solid electrolyte being a method for producing a garnet-type solid electrolyte that is represented by the following compositional formula (1) or (2) and that conducts lithium, the method comprising:
forming a mixture by mixing raw material solutions containing elements shown in the compositional formula (1) or (2) with lithium fluoride;
forming a calcined body by subjecting the mixture to a first heating treatment; and
performing main firing by subjecting the calcined body to a second heating treatment, wherein
a mixing amount of the lithium fluoride is an amount configured to substitute 1 atom or less of oxygen with fluorine:
(Li 7−3x Ga x )(La 3−y Nd y )Zr 2 O 12−z F z (1)
(Li 7−3x+y Ga x )(La 3−y Ca y )Zr 2 O 12−z F z (2)
provided that 0.1≤x≤1.0, 0<y≤0.2, and 0<z≤1.0.
4. The method for producing a solid electrolyte according to claim 3 , wherein
a temperature in the first heating treatment is 500° C. or higher and 650° C. or lower, and
a temperature in the second heating treatment is 800° C. or higher and 1000° C. or lower.
5. A secondary battery, comprising:
a positive electrode composite material containing the solid electrolyte according to claim 1 and a positive electrode active material containing lithium;
an electrode provided at one face of the positive electrode composite material; and
a current collector provided at another face of the positive electrode composite material.
6. The secondary battery according to claim 5 , wherein the positive electrode active material is a lithium composite metal oxide.
7. The secondary battery according to claim 5 , wherein the electrode is metallic lithium.
8. An electronic apparatus, comprising the secondary battery according to claim 5 .