Carbon fibers, catalyst for production of carbon fibers, and method for evaluation of carbon fibers
View Patent ↗Provided are carbon fibers with low metal ion elution amount without subjecting to high-temperature heat treatment, in which the metal ion may be sometimes precipitated on an electrode of electrochemical devices such as batteries and capacitors to cause short-circuit. The carbon fibers comprises Fe, at least one catalyst metal selected from the group consisting of Mo and V, and a carrier; wherein the carbon fibers have an R value (ID/IG) as measured by Raman spectrometry of 0.5 to 2.0 and have an electrochemical metal elution amount of not more than 0.01% by mass.
1. A catalyst for production of carbon fibers, the catalyst comprising catalyst metals and a carrier; wherein
the catalyst metals consist of Fe and Mo or consist of Fe, Mo and V, and
Mo accounts for not less than 0.1% by mol and less than 5% by mol based on Fe.
2. Carbon fibers comprising the catalyst according to claim 1 , wherein the carbon fibers have an R value (ID/IG) as measured by Raman spectroscopy of 0.5 to 2.0, and have an electrochemical metal elution amount of catalyst metal of not more than 0.01% by mass.
3. The carbon fibers according to claim 2 , wherein the carrier comprises metal oxide.
4. The carbon fibers according to claim 2 , wherein the carbon fibers have a lattice constant C0 as measured by X-ray diffraction of 0.680 nm to 0.695 nm.
5. The carbon fibers according to claim 2 , wherein {mass of Fe/(mass of Fe+mass of carrier)}×100 (% by mass) is not less than 5% by mass and not more than 30% by mass.
6. The carbon fibers according to claim 2 , wherein the carbon fibers forms aggregates, and the carbon fibers in the aggregates are not oriented in a fixed direction.
7. The carbon fibers according to claim 6 , wherein the aggregates have a 50% particle diameter (D 50 ) of not less than 3 μm and not more than 20 μm in volume-based cumulative particle size distribution as measured by laser diffraction particle size analysis.
8. A composite material comprising the carbon fibers according to claim 2 .
9. The composite material according to claim 8 , which is an electrode material.
10. An electrochemical device comprising the carbon fibers according to claim 2 .
11. The catalyst according to claim 1 , in which the catalyst metals are supported on the carrier.
12. A catalyst for production of carbon fibers, the catalyst comprising catalyst metals and a carrier; wherein
the catalyst metals consist of Fe and V or consist of Fe, Mo and V, and
V accounts for not less than 0.1% by mol and not more than 20% by mol based on Fe.
13. Carbon fibers comprising the catalyst according to claim 12 , wherein the carbon fibers have an R value (ID/IG) as measured by Raman spectroscopy of 0.5 to 2.0, and have an electrochemical metal elution amount of not more than 0.01% by mass.
14. The carbon fibers according to claim 13 , wherein the mole of V to the mole of Fe is not less than 0.1% by mol and not more than 5% by mol.
15. A catalyst for production of carbon fibers, the catalyst comprising catalyst metals and a carrier; wherein
the catalyst metals consist of Fe, Mo and V,
Mo accounts for not less than 0.1% by mol and less than 5% by mol based on Fe, and
V accounts for not less than 0.1% by mol and not more than 20% by mol based on Fe.
16. Carbon fibers comprising the catalyst according to claim 15 , wherein the carbon fibers have an R value (ID/IG) as measured by Raman spectroscopy of 0.5 to 2.0, and have an electrochemical metal elution amount of not more than 0.01% by mass.
17. The carbon fibers according to claim 16 , wherein the mole of V to the mole of Fe is not less than 0.1% by mol and not more than 5% by mol.
18. A method for producing carbon fibers, wherein the method comprises the steps of
preparing a catalyst which comprises catalyst metals and a carrier; wherein the catalyst metals consist of Fe and Mo or consist of Fe, Mo and V, and Mo accounts for not less than 0.1% by mol and less than 5% by mol based on Fe, and
reacting only a carbon source in a vapor phase using the catalyst to obtain carbon fibers having an electrochemical metal elution amount of not more than 0.01% by mass.
19. The method according to claim 18 , wherein V accounts for not less than 0.1% by mol and not more than 20% by mol based on Fe.
20. A method for producing carbon fibers, wherein the method comprises the steps of
preparing a catalyst which comprises catalyst metals and a carrier; wherein the catalyst metals consist of Fe and V or consist of Fe, Mo and V, and V accounts for not less than 0.1% by mol and not more than 20% by mol based on Fe, and
reacting only a carbon source in vapor phase using the catalyst to obtain carbon fibers having an electrochemical metal elution amount of not more than 0.01% by mass.