Active material and positive electrode and lithium-ion second battery using same

1. A method for manufacturing an active material containing a triclinic LiVOPO 4 crystal particle, the method comprising:

a step of manufacturing the crystal particle by hydrothermal synthesis;

wherein the crystal particle has a spherical form and an average particle size of 20 to 200 nm.

2. The method of claim 1 , wherein the step of manufacturing the crystal particle by hydrothermal synthesis comprises:

a first heat treatment step of heat-processing at least an aqueous phosphate compound solution and a vanadium-containing compound that are sealed in a closed container; and

a second heat treatment step of adding an Li-containing compound to the resulting product of the first heat treatment step and further heat-processing the mixture.

3. The method of claim 1 , wherein the crystal particle has a BET specific surface area of 2 to 50 m 2 /g.

4. The method of claim 2 , wherein the crystal particle has a BET specific surface area of 2 to 50 m 2 /g.

5. The method of claim 1 , wherein the crystal particle has a longer to shorter diameter ratio (longer diameter/shorter diameter) of 1 to 2.

6. The method of claim 2 , wherein the crystal particle has a longer to shorter diameter ratio (longer diameter/shorter diameter) of 1 to 2.

7. The method of claim 3 , wherein the crystal particle is a longer to shorter diameter ratio (longer diameter/shorter diameter) of 1 to 2.

8. The method of claim 4 , wherein the crystal particle is a longer to shorter diameter ratio (longer diameter/shorter diameter) of 1 to 2.

9. A method for manufacturing a positive electrode containing an active material, comprising:

a step of manufacturing the active material by the method of claim 1 .

10. A method for manufacturing a lithium-ion secondary battery including a positive electrode, comprising:

a step of manufacturing the positive electrode by the method of claim 9 .