Power storage device having olivine type positive electrode active material with oriented crystal structure
View Patent ↗An object is to increase the amount of ions capable of leaving and entering an active material so as to increase capacity of a secondary battery. The present invention relates to a manufacturing method of a power storage device including a positive electrode active material formed using a composite oxide containing at least alkali metal and transition metal. The method includes the steps of: forming a base layer over a support substrate; forming a layer of lithium iron phosphate or a layer of sodium iron phosphate over the base layer; and using a layer of single crystalline lithium iron phosphate having an olivine structure or a layer of single crystalline sodium iron phosphate having an olivine structure with crystal axes oriented in a <010> direction as the positive electrode material by converting the layer of lithium iron phosphate or the layer of sodium iron phosphate by a heat treatment.
1. A power storage device comprising:
a positive electrode including a positive electrode active material layer and a positive electrode current collector, the positive electrode active material layer in contact with a base layer over a support substrate and comprising single crystalline sodium iron phosphate layer having an olivine structure with a crystal axis oriented in a <010> direction;
a negative electrode including a negative electrode active material and a negative electrode current collector; and
a separator provided between the positive electrode and the negative electrode,
wherein a lattice constant of the base layer is equivalent to that of the single crystalline sodium iron phosphate layer.
2. The power storage device according to claim 1 , wherein the base layer is formed using a material selected from the group consisting of β-Ta, Cu 2 [Cd 0.79 Fe 0.17 Mn 0.04 ]GeS 4 , Cu 2 FeGeS 4 , CuFeS 2 , CuGaS 2 , Cu 3 [As 0.644 Sb 0.356 ]S 4 , Cu 9 Fe 9 S 16 , CaV 3 O 7 , WO 3 .H 2 O, Fe 2 SiO 4 , Mg 2 SiO 4 , Li 3 PO 4 , Cu 3 Fe 4 [VO 4 ] 6 , [Fe 0.292 Mg 0.708 ] 2 SiO 4 , NaSiO 3 , and LiAlSiO 4 .H 2 O.
3. The power storage device according to claim 1 , wherein the support substrate is selected from the group consisting of a silicon substrate, a sapphire substrate, a glass substrate and a ceramic substrate.
4. The power storage device according to claim 1 , wherein the support substrate is a silicon substrate, and the base layer is formed over a (100) plane of the silicon substrate.
5. The power storage device according to claim 1 further comprising an electrolyte, wherein the positive electrode and the negative electrode and the separator are provided in the electrolyte.
6. A power storage device comprising:
a positive electrode including a positive electrode active material layer and a positive electrode current collector, the positive electrode active material layer in contact with a base layer over a support substrate and comprising single crystalline lithium iron phosphate layer having an olivine structure with a crystal axis oriented in a <010> direction;
a negative electrode including a negative electrode active material and a negative electrode current collector; and
a separator provided between the positive electrode and the negative electrode,
wherein a lattice constant of the base layer is equivalent to that of the single crystalline lithium iron phosphate layer.
7. The power storage device according to claim 6 , wherein the base layer is formed using a material selected from the group consisting of β-Ta, Cu 2 [Cd 0.79 Fe 0.17 Mn 0.04 ]GeS 4 , Cu 2 FeGeS 4 , CuFeS 2 , CuGaS 2 , Cu 3 [As 0.644 Sb 0.356 ]S 4 , Cu 9 Fe 9 S 16 , CaV 3 O 7 , WO 3 .H 2 O, Fe 2 SiO 4 , Mg 2 SiO 4 , Li 3 PO 4 , Cu 3 Fe 4 [VO 4 ] 6 , [Fe 0.292 Mg 0.708 ] 2 SiO 4 , NaSiO 3 , and LiAlSiO 4 .H 2 O.
8. The power storage device according to claim 6 , wherein the support substrate is selected from the group consisting of a silicon substrate, a sapphire substrate, a glass substrate and a ceramic substrate.
9. The power storage device according to claim 6 , wherein the support substrate is a silicon substrate, and the base layer is formed over a (100) plane of the silicon substrate.
10. The power storage device according to claim 6 further comprising an electrolyte, wherein the positive electrode and the negative electrode and the separator are provided in the electrolyte.