Carbon particles for negative electrode of lithium ion secondary battery, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
View Patent ↗Disclosed are carbon particles for a negative electrode of a lithium ion secondary battery, the carbon particles having a pore volume of pores having a size of 2×10 to 2×10 4 Å, of 0.1 ml/g or less with respect to the mass of the carbon particles; having an interlayer distance d(002) of a graphite crystal as determined by an X-ray diffraction analysis, of 3.38 Å or less; having a crystallite size Lc in the C-axis direction of 500 Å or more; and having a degree of circularity of the particle cross-section in the range of 0.6 to 0.9. Therefore, the carbon particles for the negative electrode of the lithium ion secondary battery enables to have high capacity and have superior rapid charge characteristics, a negative electrode for a lithium ion secondary battery using the carbon particles, and a lithium ion secondary battery can be provided.
1. Carbon particles for a negative electrode of a lithium ion secondary battery, the carbon particles having a pore volume of pores having a size of 2×10 to 2×10 4 Å, of 0.07 ml/g or less with respect to the mass of the carbon particles; having an interlayer distance d(002) of a graphite crystal as determined by an X-ray diffraction analysis, of 3.38 Å or less; having a crystallite size Lc in the C-axis direction of 500 Å or more; and having a degree of circularity of the particle cross-section in the range of 0.6 to 0.9.
2. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 , wherein the carbon particles have an exothermic peak at a temperature in the range of 550° C. or higher to 650° C. or lower in a differential thermal analysis in an air stream, and have a peak area in the range of 100 μV·s/mg or larger to 2100 μV·s/mg or smaller at a rate of temperature increase of 5° C./min.
3. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 , wherein the average particle size as measured with a laser diffraction type particle size distribution analyzer is in the range of 1 to 100 μm.
4. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 , wherein the N 2 specific surface area as determined by a nitrogen adsorption analysis at 77 K is 10 m 2 /g or less.
5. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 , wherein the bulk density is 0.7 g/ml or greater.
6. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 , wherein the true specific gravity is 2.2 or greater.
7. A negative electrode for the lithium secondary battery, comprising the carbon particles for the negative electrode of the lithium ion secondary battery according to claim 1 .
8. A lithium ion secondary battery, comprising the negative electrode according to claim 7 and a positive electrode containing a lithium compound.
9. Carbon particles for a negative electrode of a lithium ion secondary battery, the carbon particles having a pore volume of pores having a size of 2×10 to 2×10 4 Å, of 0.07 ml/g or less with respect to the mass of the carbon particles; having an interlayer distance d(002) of a graphite crystal as determined by an X-ray diffraction analysis, of 3.38 Å or less; having a crystallite size Lc in the C-axis direction of 500 Å or more; and being configured to have, in a state of being produced into a negative electrode for a lithium ion secondary battery, a degree of circularity of the particle cross-section in the range of 0.6 to 0.9.
10. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 , wherein the carbon particles have an exothermic peak at a temperature in the range of 550° C. or higher to 650° C. or lower in a differential thermal analysis in an air stream, and have a peak area in the range of 100 μV·s/mg or larger to 2100 μV·s/mg or smaller at a rate of temperature increase of 5° C./min.
11. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 , wherein the average particle size as measured with a laser diffraction type particle size distribution analyzer is in the range of 1 to 100 μm.
12. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 , wherein the N2 specific surface area as determined by a nitrogen adsorption analysis at 77 K is 10 m 2 /g or less.
13. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 , wherein the bulk density is 0.7 g/ml or greater.
14. The carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 , wherein the true specific gravity is 2.2 or greater.
15. A negative electrode for the lithium secondary battery, comprising the carbon particles for the negative electrode of the lithium ion secondary battery according to claim 9 .
16. A lithium ion secondary battery, comprising the negative electrode according to claim 15 and a positive electrode containing a lithium compound.