Carbon material for nonaqueous-electrolyte secondary-battery negative electrode and process for producing the same, negative electrode including the same for nonaqueous secondary battery, and nonaqueous-electrolyte secondary battery
View Patent ↗A carbon material for nonaqueous-electrolyte secondary-battery negative electrode is provided, which satisfies the followings (1) and (2): (1) the carbon material has an aspect ratio of 10 or less; (2) the amount of CO eliminated from the carbon material during heating to 1,000° C., as determined with a temperature programmed decomposition mass spectrometer (TPD-MS), is 2-15 μmol/g.
1. A carbon material, wherein:
the carbon material has an aspect ratio of 10 or less; and
an amount of CO eliminated from the carbon material during heating to 1,000° C., as determined with a temperature programmed decomposition mass spectrometer (TPD-MS), is 2-15 μmol/g.
2. The carbon material according to claim 1 , wherein the carbon material has a 002-plane interplanar spacing (d002), as determined by wide-angle X-ray diffractometry, of 0.337 nm or less.
3. The carbon material according to claim 1 , wherein the carbon material has a specific surface area of 0.5-8 m 2 /g.
4. The carbon material according to claim 1 , wherein the carbon material has an average degree of circularity, as determined with a flow type particle analyzer, of 0.9 or higher.
5. A negative electrode, comprising:
a current collector; and
an active-material layer formed on the current collector;
wherein the active-material layer comprises the carbon material according to claim 1 .
6. A lithium ion secondary battery, comprising:
a positive electrode that is capable of occluding and releasing lithium ions;
the negative electrode according to claim 5 ; and
an electrolyte.
7. A process for producing a carbon material for nonaqueous-electrolyte secondary-battery negative electrodes, which comprises subjecting a raw carbon material to a mechanical treatment, wherein the raw carbon material has a 002-plane interplanar spacing (d002), as determined by wide-angle X-ray diffractometry, of 0.337 nm or less, a tap density of 0.8 g/cm 3 or higher and a value of Raman R of 0.2-0.5, in which the value of Raman R is the ratio of the intensity of a peak appearing around 1,360 cm −1 to the intensity of a peak appearing around 1,580 cm −1 , in an argon ion laser Raman spectrum that has a value of Raman R;
wherein:
the obtained carbon material for nonaqueous-electrolyte secondary-battery negative electrodes has an aspect ratio of 10 or less; and
an amount of CO eliminated from the obtained carbon material during heating to 1,000° C., as determined with a temperature programmed decomposition mass spectrometer
(TPD-MS), is 2-15 μmol/g.
8. The process for producing a carbon material for nonaqueous-electrolyte secondary-battery negative electrodes according to claim 7 , wherein the mechanical treatment is a treatment in which an apparatus that includes a rotor which comprises a casing and a plurality of blades disposed inside the casing is used to treat the raw carbon material at a peripheral speed of the rotor of 50-300 m/sec.
9. The process for producing a carbon material for nonaqueous-electrolyte secondary-battery negative electrodes according to claim 7 , wherein the raw carbon material is a multilayered raw carbon material which comprises a graphitic particle and amorphous carbon that covers the surface of the graphitic particle.
10. The carbon material according to claim 1 , wherein the aspect ratio is 7 or less.
11. The carbon material according to claim 1 , wherein the aspect ratio is 3 or less.
12. The carbon material according to claim 1 , wherein the amount of CO eliminated from the carbon material during heating to 1,000° C. is 2.3-15 μmol/g.
13. The carbon material according to claim 1 , wherein the amount of CO eliminated from the carbon material during heating to 1,000° C. is 2-10 μmol/g.
14. The carbon material according to claim 1 , wherein the amount of CO eliminated from the carbon material during heating to 1,000° C. is 5.1-10 μmol/g.
15. The carbon material according to claim 1 , wherein the carbon material has a specific surface area of 3-8 m 2 /g.
16. The carbon material according to claim 1 , wherein the carbon material has a specific surface area of 0.5-6 m 2 /g.
17. The carbon material according to claim 1 , wherein the carbon material has a specific surface area of 3-6 m 2 /g.
18. The carbon material according to claim 1 , wherein the carbon material has an average degree of circularity, as determined with a flow type particle analyzer, of 0.93 or higher.
19. The carbon material according to claim 1 , wherein:
the aspect ratio is 5 or less;
the amount of CO eliminated from the carbon material during heating to 1,000° C. is 3.4-15 μmol/g;
the carbon material has a 002-plane interplanar spacing (d002), as determined by wide-angle X-ray diffractometry, of 0.337 nm or less;
the carbon material has a specific surface area of 1.5-7 m 2 /g; and
the carbon material has an average degree of circularity, as determined with a flow type particle analyzer, of 0.93 or higher.
20. The carbon material according to claim 1 , wherein:
the aspect ratio is 3 or less;
the amount of CO eliminated from the carbon material during heating to 1,000° C. is 5.1-10 μmol/g;
the carbon material has a 002-plane interplanar spacing (d002), as determined by wide-angle X-ray diffractometry, of 0.337 nm or less;
the carbon material has a specific surface area of 3-6 m 2 /g; and
the carbon material has an average degree of circularity, as determined with a flow type particle analyzer, of 0.93 or higher.