Active material and method of manufacturing active material
View Patent ↗An active material capable of forming an electrochemical device excellent in its discharge capacity and rate characteristic is provided. The active material in accordance with a first aspect of the present invention comprises a compound particle containing a compound having a composition represented by the following chemical formula (1), a carbon layer covering the compound particle, and a carbon particle. The active material in accordance with a second aspect of the present invention comprises a carbon particle and a compound particle having an average primary particle size of 0.03 to 1.4 μm, being carried by the carbon particle, and containing a compound represented by the following chemical formula (1): Li a MXO 4 (1) where a satisfies 0.9≦a≦2, M denotes one species selected from the group consisting of Fe, Mn, Co, Ni, and VO, and X denotes one species selected from the group consisting of P, Si, S, V, and Ti.
1. An active material comprising:
a compound particle containing LiVOPO 4 ;
a carbon layer covering the compound particle; and
a carbon particle,
wherein:
the carbon layer has an average thickness of 1 to 30 nm;
the compound particle has an average primary particle size D 1 , the carbon particle has an average primary particle size D 2 , and the ratio D 1 /D 2 satisfies 0.03≦D 1 /D 2 <1.
2. The active material according to claim 1 , wherein the compound particle is a primary particle.
3. The active material according to claim 1 , wherein the carbon particle has an average primary particle size of 10 to 100 nm.
4. The active material according to claim 1 , wherein the compound particle is carried by a surface of the carbon particle.
5. A method of manufacturing an active material comprising:
a hydrothermal synthesizing step of heating a mixture including a lithium compound, a first compound containing V, a second compound containing P, an organic compound, a carbon particle, and water under pressure; and
a firing step of firing the mixture after the heating under pressure in the hydrothermal synthesizing step;
wherein:
the active material comprises:
a compound particle containing LiVOPO 4 ;
a carbon layer covering the compound particle; and
a carbon particle;
the carbon layer has an average thickness of 1 to 30 nm;
the compound particle has an average primary particle size D 1 , the carbon particle has an average primary particle size D 2 , and the ratio D 1 /D 2 satisfies 0.03≦D 1 /D 2 <1.
6. The method of manufacturing an active material according to claim 5 , wherein:
the first compound is V 2 O 5 ; and
the second compound is a phosphoric acid or phosphate.
7. The method of manufacturing an active material according to claim 5 , wherein the organic compound is an organic acid or alcohol.
8. The method of manufacturing an active material according to claim 7 , wherein the organic acid is ascorbic acid.
9. The method of manufacturing an active material according to claim 5 , wherein the carbon particle is carbon black.
10. The method of manufacturing an active material according to claim 5 , wherein the lithium compound is LiOH.H 2 O.
11. An active material comprising:
a carbon particle; and
a compound particle having an average primary particle size, D 1 , of 0.03 to 1.4 μm, being carried by a surface of the carbon particle, and containing LiVOPO 4 ,
wherein the carbon particle has an average primary particle size D 2 , and the ratio D 1 /D 2 satisfies 0.03≦D 1 /D 2 <1.
12. The active material according to claim 11 , wherein the average primary particle size of the carbon particle is 0.01 to 1 μm.
13. A method of manufacturing an active material comprising:
A hydrothermal synthesizing step of heating a mixture including a lithium compound, a first compound containing one species selected from the group consisting of Fe, Mn, Co, Ni, and V, a second compound containing one species selected from the group consisting of P, Si, S, V, and Ti, a carbon particle, and water under pressure; and
a firing step the mixture after the heating under pressure in the hydrothermal synthesizing step;
wherein:
the active material comprises:
a carbon particle; and
a compound particle having an average primary particle size, D 1 , of 0.03 to 1.4 μm, being carried by a surface of the carbon particle, and containing LiVOPO 4 ; and
the carbon particle has an average primary particle size D 2 , and the ratio D 1 /D 2 satisfies 0.03≦D 1 /D 2 <1.
14. The method of manufacturing an active material according to claim 13 , wherein:
the first compound is V 2 O 5 ; and
the second compound is a phosphoric acid or phosphate.
15. The method of manufacturing an active material according to claim 13 , wherein the carbon particle is activated carbon or carbon black.
16. The method of manufacturing an active material according to claim 13 , wherein the lithium compound is LiOH.H 2 O.