Electrode material, method for producing the same, electrode and battery
An electrode material containing an electrode active material, and a carbonaceous coating film which covers the electrode active material and contains sulfur; and an electrode material including a secondary particle including a plurality of primary particles as the electrode active material, wherein the primary particles are covered with a carbonaceous coating film so that the carbonaceous coating film is interposed between the primary particles and the carbonaceous coating film contains sulfur.
1. An electrode material comprising:
an electrode active material; and
a carbonaceous coating film that covers the electrode active material and contains sulfur and further contains lithium; wherein the content of lithium in the carbonaceous coating film is 0.1 to 10 mass % in terms of lithium atoms.
2. The electrode material according to claim 1 , wherein
the lithium in the carbonaceous coating film is from a lithium compound selected from the group consisting of Li, LiCl, LiBr, Li 2 CO 3 , LiNO 3 , Li 2 SO 4 , Li 3 PO 4 , LiOH, LiCH 3 COO, (COOLi) 2 , LiC 2 H 5 O, and Li 4 (CH 3 ) 4 ;
the generation of C—S bonding C—Li bonding is recognized in the carbonaceous coating film by X-ray photoelectron spectroscopy; the electrode active material includes at least one selected from the group consisting of lithium cobaltate, lithium nickelate, lithium manganite, lithium, lithium titanate, and a compound represented by Li x A y B z PO 4 , wherein
A is one or more selected from the group consisting of Co, Mn, Ni, Fe, Cu, and Cr,
B is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare-earth elements,
0≦x<2,
0<y<1.5
0≦z<1.5; and
the resistivity of the electrode material is 3300 Ωcm or lower.
3. An electrode material comprising a secondary particle that includes a plurality of primary particles as an electrode active material, wherein the primary particles are covered with a carbonaceous coating film and, the carbonaceous coating film is interposed between the primary particles and contains sulfur and further contains lithium; wherein the content of lithium in the carbonaceous coating film is 0.1 to 10 mass % in terms of lithium atoms.
4. The electrode material according to claim 3 , wherein
the lithium in the carbonaceous coating film is from a lithium compound selected from the group consisting of Li, LiCl, LiBr, Li 2 CO 3 , LiNO 3 , Li 2 SO 4 , Li 3 PO 4 , LiOH, LiCH 3 COO, (COOLi) 2 , LiC 2 H 5 O, and Li 4 (CH 3 ) 4 ;
the generation of C—S bonding C—Li bonding is recognized in the carbonaceous coating film by X-ray photoelectron spectroscopy; the electrode active material includes at least one selected from the group consisting of lithium cobaltate, lithium nickelate, lithium manganite, lithium, lithium titanate, and a compound represented by Li x A y B z PO 4 , wherein
A is one or more selected from the group consisting of Co, Mn, Ni, Fe, Cu, and Cr,
B is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare-earth elements,
0≦x<2,
0<y<1.5
0≦z<1.5; and
the resistivity of the electrode material is 3300 Ωcm or lower.
5. A method for producing an electrode material, the method comprising:
preparing slurry including (a) an electrode active material or a precursor of the electrode active material, (b) an organic compound, (c) sulfur or a sulfur compound, and (d) lithium or a lithium compound;
spraying and drying the slurry to generate a granular material; and
performing a heat treatment on the granular material under a non-oxidizing atmosphere of 500° C. or higher and 1000° C. or lower to obtain an electrode material formed of an electrode active material and a carbonaceous coating film covering the electrode active material and containing sulfur; wherein the content of lithium in the carbonaceous coating film is 0.1 to 10 mass % in terms of lithium atoms.
6. An electrode which is formed using an electrode material, wherein the electrode material includes an electrode active material and a carbonaceous coating film covering the electrode active material and containing sulfur and further contains lithium; wherein the content of lithium in the carbonaceous coating film is 0.1 to 10 mass % in terms of lithium atoms.
7. An electrode is formed using an electrode material, wherein the electrode material includes a secondary particle that includes a plurality of primary particles as an electrode active material, the primary particles are covered with a carbonaceous coating film so that the carbonaceous coating film is interposed between the primary particles, and the carbonaceous coating film contains sulfur and further contains lithium; wherein the content of lithium in the carbonaceous coating film is 0.1 to 10 mass % in terms of lithium atoms.
8. A battery having a positive electrode which is the electrode according to claim 6 .
9. A battery having a positive electrode which is the electrode according to claim 7 .
10. The electrode material according to claim 1 , wherein the thickness of the carbonaceous coating film is 0.1 to 20 nm.
11. The electrode material according to claim 1 , wherein the content of sulfur in the carbonaceous coating film is 0.1 to 50 mass % in terms of sulfur atoms.
12. The electrode material according to claim 3 , wherein the thickness of the carbonaceous coating film is 0.1 to 20 nm.
13. The electrode material according to claim 3 , wherein the content of sulfur in the carbonaceous coating film is 0.1 to 50 mass % in terms of sulfur atoms.
14. The method for producing the electrode material according to claim 5 , wherein the (b) organic compound is at least one selected from the group consisting of: polyvinyl alcohol, polyvinyl pyrrolidone, cellulose, starch, gelatin, carboxyl methyl cellulose, methyl cellulose, hydroxy methyl cellulose, hydroxy ethyl cellulose, polyacryl acid, polystyrene sulfonate, polyacryl amide, polyvinyl acetate, glucose, fructose, galactose, manose, maltose, sucrose, lactose, glycogen, pectin, alginic acid, glucomannan, chitin, hyaluronic acid, chondroitin, agarose, polyether, and polyalcohol.
15. The electrode according to claim 6 , wherein the thickness of the carbonaceous coating film is 0.1 to 20 nm.
16. The electrode according to claim 7 , wherein an average particle size of the primary particles is 0.01 to 20 μm.
17. The method for producing the electrode material according to claim 5 , wherein the content of sulfur in the carbonaceous coating film is 0.1 to 50 mass % in terms of sulfur atoms.
18. The method for producing the electrode material according to claim 5 , wherein the thickness of the carbonaceous coating film is 0.1 to 20 nm.
19. The method for producing the electrode material according to claim 5 , wherein the granular material is subjected to the heat treatment under the non-oxidizing atmosphere of 500° C. to 750° C.