EP3443152A1 - Polyacrylonitrile-based graphite fiber - Google Patents
Polyacrylonitrile-based graphite fiberInfo
- Publication number
- EP3443152A1 EP3443152A1 EP17720376.7A EP17720376A EP3443152A1 EP 3443152 A1 EP3443152 A1 EP 3443152A1 EP 17720376 A EP17720376 A EP 17720376A EP 3443152 A1 EP3443152 A1 EP 3443152A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- graphite fiber
- fiber
- polyacrylonitrile
- graphite
- particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000835 fiber Substances 0.000 title claims abstract description 121
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 95
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 88
- 239000010439 graphite Substances 0.000 title claims abstract description 88
- 229920002239 polyacrylonitrile Polymers 0.000 title claims abstract description 50
- 239000000463 material Substances 0.000 claims abstract description 26
- 239000011229 interlayer Substances 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 42
- 239000002245 particle Substances 0.000 claims description 40
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 38
- 239000004917 carbon fiber Substances 0.000 claims description 38
- 239000002243 precursor Substances 0.000 claims description 25
- 238000005087 graphitization Methods 0.000 claims description 20
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 19
- 229920000642 polymer Polymers 0.000 claims description 16
- 239000004753 textile Substances 0.000 claims description 16
- 239000004744 fabric Substances 0.000 claims description 12
- 238000009987 spinning Methods 0.000 claims description 11
- 239000003054 catalyst Substances 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims description 8
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 8
- 150000001247 metal acetylides Chemical class 0.000 claims description 8
- 229910052759 nickel Inorganic materials 0.000 claims description 8
- 229910052710 silicon Inorganic materials 0.000 claims description 8
- 229910052719 titanium Inorganic materials 0.000 claims description 8
- 239000002783 friction material Substances 0.000 claims description 7
- 229910001416 lithium ion Inorganic materials 0.000 claims description 7
- 238000003763 carbonization Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 150000004767 nitrides Chemical class 0.000 claims description 6
- 239000000654 additive Substances 0.000 claims description 5
- 230000000996 additive effect Effects 0.000 claims description 5
- 239000011231 conductive filler Substances 0.000 claims description 5
- 239000010410 layer Substances 0.000 claims description 5
- 229910052796 boron Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 238000010612 desalination reaction Methods 0.000 claims description 4
- 238000009792 diffusion process Methods 0.000 claims description 4
- 239000007772 electrode material Substances 0.000 claims description 4
- 238000005868 electrolysis reaction Methods 0.000 claims description 4
- 239000000446 fuel Substances 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 229910052748 manganese Inorganic materials 0.000 claims description 4
- 230000006641 stabilisation Effects 0.000 claims description 4
- 238000011105 stabilization Methods 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 239000002759 woven fabric Substances 0.000 claims description 4
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000010405 anode material Substances 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 claims description 3
- 229910052681 coesite Inorganic materials 0.000 claims description 2
- 229910052906 cristobalite Inorganic materials 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 229910052682 stishovite Inorganic materials 0.000 claims description 2
- 229910052905 tridymite Inorganic materials 0.000 claims description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims 1
- 239000000377 silicon dioxide Substances 0.000 claims 1
- 235000012239 silicon dioxide Nutrition 0.000 claims 1
- 239000011302 mesophase pitch Substances 0.000 description 10
- 239000002956 ash Substances 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000007380 fibre production Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000000746 purification Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 238000002166 wet spinning Methods 0.000 description 3
- 235000002918 Fraxinus excelsior Nutrition 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 150000002902 organometallic compounds Chemical class 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000003313 weakening effect Effects 0.000 description 2
- LVGUZGTVOIAKKC-UHFFFAOYSA-N 1,1,1,2-tetrafluoroethane Chemical compound FCC(F)(F)F LVGUZGTVOIAKKC-UHFFFAOYSA-N 0.000 description 1
- 239000004338 Dichlorodifluoromethane Substances 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 1
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000578 dry spinning Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
- D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F1/00—General methods for the manufacture of artificial filaments or the like
- D01F1/02—Addition of substances to the spinning solution or to the melt
- D01F1/10—Other agents for modifying properties
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
- D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
- D01F9/225—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles from stabilised polyacrylonitriles
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
- D01F11/12—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with inorganic substances ; Intercalation
- D01F11/121—Halogen, halogenic acids or their salts
Definitions
- the present invention relates to a polyacrylonitrile-based graphite fiber, a textile fabric containing the polyacrylonitrile-based graphite fiber, a method for the manufacture of the graphite fiber and the textile fabric and its use as battery felts used in redox-flow batteries or NaS batteries, for carbon fiber papers used as gas diffusion layers in fuel cells and electrolysis cells, in satellite structure parts, in heat spreaders in the area of thermal management, as electrode material or for current collectors in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
- Graphite fibers compared to carbon fibers are characterized by their high grade of graphitization resulting in the molecular structure and microstructure of graphite.
- the microstructure of graphite is defined by the crystallographic parameters (i) interlayer spacing (d002 distance) which is the distance between adjacent molecular layers of covalently bonded sp 2 -hybridized carbon and (ii) mean crystallite size (Lc) which is a measure of the extension of the perfect graphite structure within a material. In a perfect graphite single crystal the d002 distance is 0.3354 nm and Lc corresponds to the size of the macroscopic crystal.
- d002 distance of a carbon fiber which is based on polyacrylonitrile is about 0.345 nm and Lc is about 3 nm after carbonization at 1400°C, one can talk about a graphite fiber, if the d002 distance is 0.344 or lower accompanied with an increase of Lc to 12 nm or higher.
- Graphite fibers feature high electrical and thermal conductivity rather than, for example, high tensile strength as carbon fibers do. Thus, the focus of graphite fibers lies on applications requiring suitable thermo-electrical properties rather than good mechanical properties. Graphite fibers can, for example, be obtained by
- mesophase pitch-based carbon fibers graphitization of mesophase pitch-based carbon fibers. That means, carbon fibers based on mesophase pitch are heated to a sufficiently high temperature, typically above 2,200°C, so that the apriori amorphous carbon converts into a graphitic structure.
- Mesophase pitch-based carbon fibers are very expensive.
- mesophase pitch-based carbon fibers cost about 100 times more.
- Polyacrylonitrile-based carbon fibers do not graphitize as good as mesophase pitch-based carbon fibers even if they are heated up to 2,200°C or above.
- the d002 distance and the Lc of a polyacrylonitrile-based carbon fiber which is carbonized at a temperature of 2,500°C are about 0.343 nm and 5 nm respectively.
- JP2014167039 (A) a catalytic graphitization method is described, wherein the activation energy of the carbonization reaction can be lowered so that the respective carbon fiber carbonized at lower temperatures has the same crystallinity as a typical polyacrylonitrile-based carbon fiber carbonized at higher temperatures.
- the method includes a copolymeri- zation of polyacrylonitrile with an organometallic compound of a group VIII metal. The so obtained copolymer is then used as a precursor polymer in the known carbon fiber production method. While the performance of a copolymerization method with an organometallic compound is a rather expensive method and the reached crystallinity of the resulting carbon fiber still not exceeds that of typical
- the object of the present invention to provide a graphite fiber with a high grade of graphitization which can be manufactured by a simple and cost efficient method.
- the present invention provides a polyacrylonitrile-based graphite fiber, wherein the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.344 nm, preferably below 0.341 nm and a mean crystallite size (Lc) of at least 12 nm, preferably at least 20 nm.
- d002 distance interlayer spacing
- Lc mean crystallite size
- the graphite fiber of the present invention has a high thermal conductivity of about 1 100 W/m-K.
- the electrical conductivity is also very high compared to standard carbon fibers.
- the graphite fiber of the present invention is less cost-intensive than mesophase-pitch based graphite fibers, since it is based on polyacrylonitrile.
- polyacrylonitrile-based means that the graphite fiber is obtained by starting with polyacrylonitrile as the base material for the respective precursor fiber as it is analogously the case with polyacrylonitrile-based carbon fibers which are well known in the art.
- polyacrylonitrile-based also includes co-polymers of polyacrylonitrile with other monomers.
- the graphite fiber of the present invention is not limited with regard to any coatings or the like being present, for example, on the surface of the fiber. Any such additional material is not encompassed by the expression "the material of the graphite fiber".
- the "material of the graphite fiber” rather refers to the graphitic material based on polyacrylonitrile. According to a preferred embodiment of the present invention the material of the polyacrylonitrile-based graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.341 nm, preferably below 0.339 nm after being heated to a temperature of at least 2,500°C for 30 minutes.
- the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.339 nm, preferably below 0.337 nm after being heated to a temperature of at least 3,000°C for 30 minutes.
- the material of the fiber is, thus, getting close to the ideal graphite structure featuring high thermal and electrical conductivity.
- the frictional properties are advantageous, in particular for applications like as friction materials in clutches, wet-friction, brake discs and brake pads.
- the material of the polyacrylonitrile-based graphite fiber exhibits a mean crystallite size (Lc) of at least 12 nm, preferably at least 20 nm after being heated to a temperature of at least 2,500°C for 30 minutes. Even more preferably, the material of the graphite fiber exhibits a mean crystallite size (Lc) of at least 20 nm, preferably at least 30 nm after being heated to a temperature of at least 3,000°C for 30 minutes.
- This high grade of crystallinity also leads to high thermal and electrical conductivity and advantageous frictional properties.
- the polyacrylonitrile-based graphite fiber according to the present invention is not limited with regard to any other ingredients within the fiber besides the graphitic polyacrylonitrile-based material.
- the graphite fiber contains one or more elements selected from the group consisting of Ca, Ti, Si, B, V, Cr, Ni, Mn, Fe, W and Cu in the form of its carbides, oxides, borides and/or nitrides, wherein the carbides, oxides, borides or nitrides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 ⁇ , preferably 10 nm to 0.35 ⁇ and more preferably 50 nm to 0.1 ⁇ .
- such particles may have some advantageous functions depending on the final application of the fiber.
- the mean particle size corresponds to the d50-value. This particle size can be measured by using the laser diffraction method according to ISO 13320. The main function of these particles lies in the catalysis of the graphitization reaction which leads to the high grade of crystallinity according to the present invention of the material of the graphite fiber.
- the graphite fiber comprises one or more elements selected from the group consisting of Ti, Si and Ni in the form of its carbides and/or oxides, wherein the carbides or oxides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 ⁇ , preferably 10 nm to 0.35 ⁇ and more preferably 50 nm to 0.1 ⁇ .
- the particles are present in an amount of 0.01 to 3 weight-percent (wt.-%), preferably of 0.01 to 1 .5 wt-%, based on the total weight of the graphite fiber. Within these ranges the highest grades of graphitization can be observed. The amount can be measured simply by burning the graphite fiber in an oxygen-containing atmosphere, weighing the residual ashes and analyzing the ashes.
- the total ash content of the graphite fiber of the present invention is not particularly limited.
- the graphite fiber has an ash content in the range 0.01 to 3 wt-%, preferably of 0.01 to 1 .5 wt-%, based on the total weight of the graphite fiber, wherein at least 60% the ash consists of NiC, NiO, TiC, T1O2, SiC, S1O2 or mixtures thereof.
- the graphite fiber has an ash content of below 0.1 wt-%, preferably below 0.05 wt-% and more preferably below 0.01 wt-% based on the total weight of the graphite fiber and that the fiber is porous and contains voids having a mean diameter in the range of 5 nm to 1 ⁇ .
- a fiber can be obtained according to a preferred method described below, wherein the graphite fiber is subjected to a purification method, for example, with chlorine gas converting the particles mentioned above into volatile substances and, thus, removing them from the fiber.
- the preferred graphite fiber of the present invention is of high purity and high crystallinity.
- the residual pores resulting from the particles previously present in the graphite fiber preferably have mean diameter in the range of 5 nm to 1 ⁇ , preferably 10 nm to 0.35 ⁇ and more preferably 50 nm to 0.1 ⁇ . It is assumed that the particles mentioned above are completely removed during the purification process leaving pores having the corresponding size of the particles.
- the pore volume of such a purified fiber is preferably in the range of 0.005 Vol.-% to 1 .5 Vol.-%.
- the polyacrylonitrile-based graphite fiber of the present invention can be further processed into any textile.
- the present invention relates to a textile fabric comprising the polyacrylonitrile-based graphite fiber of the present invention being in the form of a woven fabric, a nonwoven or a paper.
- These textiles can be advantageously used as battery felts used in redox-flow batteries or NaS batteries, for carbon fiber papers used as gas diffusion layers in fuel cells and electrolysis cells, in satellite structure parts, in heat spreaders in the area of thermal
- batteries as electrode material or for current collectors in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
- batteries preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
- the present invention relates to a method for the manufacture of a graphite fiber comprising the following steps:
- the graphite fiber of the present invention is manufactured by the method of the present invention.
- liquid polymer comprising polyacrylonitrile in the context of the present invention encompasses any liquid, including but not limited to solutions or melts, containing any polyacrylonitrile-containing polymer, including but not limited to a polyacrylonitrile polymer, a copolymer with polyacrylonitrile. Any known
- polyacrylonitrile-based precursor compositions for carbon fiber production can be used as the liquid polymer.
- step b) work as graphitization catalysts in the later
- the particles added in step b) comprise carbide or oxide particles of Ti, Si or Ni and the particles have a mean particle size in the range of 5 nm to 1 ⁇ , preferably in the range of 10 nm to 0.35 ⁇ and more preferably in the range of 50 nm to 0.1 ⁇ .
- Most preferred are T1O2 and SiC particles having the respective particle size. The preferred particles, in particular, show a high catalytic effect.
- the particles are added in an amount of 0.05 to 1 .5 wt.-%, more preferably 0.1 to 1 wt.-% based on the total weight of the liquid polymer provided in step a). If the liquid polymer is a solution, then the amount of added particles refers to the proportion of polymer present in the solution.
- the kind of spinning method in step c) is not particularly limited. Possible spinning methods are air gap spinning, dry spinning, melt spinning and wet spinning.
- the spinning step c) is a wet spinning method, in particular solvent spinning, or air gap spinning.
- the wet spinning and air gap spinning method are known in the art of polyacrylonitrile-based carbon fiber production.
- the graphite fiber of the present invention can be further treated by various methods.
- the graphite fiber is thermally treated at above 1000°C in the presence of chlorine gas or chlorofluorocarbon gas. This treatment leads to a leach out of the particles added in step b) and, thus, to a purification of the graphite fiber.
- Preferred chlorofluorocarbon gases are dichlorodifluoromethane and 1 ,1 ,1 ,2-tetrafluorethane.
- the present invention relates to a method for the manufacture of a textile fabric incorporating the method for the manufacture of a graphite fiber according to the present invention wherein additionally a textile fabric forming process step is performed either with the precursor fiber before step d), with the stabilized precursor fiber before step e), with the carbon fiber before step f) or with the graphite fiber after step f) and that the textile fabric forming process step is one of a woven fabric forming process step, a nonwoven forming process step or a paper forming process step.
- the above described preferred purification step can be performed before or after the textile forming process step.
- the present invention relates to the use of the graphite fiber according to the present invention as conductive filler for polymers or as additive for friction materials.
- the fibers are preferably cut into a suitable length before use.
- the present invention relates to the use of the textile fabric according to the present invention as an electrode material or a current collector in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, as a gas diffusion layer in electrolysis or in fuel cells, as a catalyst carrier, as a friction material, preferably in the form of a composite material, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches or as a heat spreader in the area of thermal management, in particular for the distribution of heat.
- batteries preferably redox-flow batteries, LiS batteries and Li-ion batteries
- a gas diffusion layer in electrolysis or in fuel cells
- a catalyst carrier as a friction material, preferably in the form of a composite material, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches or as a heat spreader in the area of thermal management, in particular for the distribution of heat.
- Figure 1 A diagram showing the differences in d002 distance between mesophase pitch based carbon fibers and PAN-based carbon fibers in dependence on the temperature.
- Figure 2 A diagram showing the differences in crystallite size (Lc) between mesophase pitch and PAN in dependence on the temperature. (Source: M.R.
- Figure 3 A diagram showing measurement results. Examples
- polyacrylonitrile fibers With each of the batches polyacrylonitrile fibers have been spun to precursor fibers by a solvent-spinning method.
- the respective precursor fibers were further processed by a stabilization process which is heating the precursor fiber under tension in the presence of oxygen, followed by a carbonization step in which the fiber is heated up to 1400°C in the absence of oxygen.
- the method steps of solvent- spinning, stabilization and carbonization are well known methods in the field of carbon fiber production.
- mesophase pitch fibers For comparative purposes, mesophase pitch fibers have been heated as well up to 2800°C for 30 minutes. The crystallographic results are as well given in figure 3.
Abstract
The present invention relates to a polyacrylonitrile-based graphite fiber, characterized in that the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.344 nm, preferably below 0.341 nm and a mean crystallite size (Lc) of at least 12 nm, preferably at least 20 nm.
Description
POLYACRYLONITRILE-BASED GRAPHITE FIBER
The present invention relates to a polyacrylonitrile-based graphite fiber, a textile fabric containing the polyacrylonitrile-based graphite fiber, a method for the manufacture of the graphite fiber and the textile fabric and its use as battery felts used in redox-flow batteries or NaS batteries, for carbon fiber papers used as gas diffusion layers in fuel cells and electrolysis cells, in satellite structure parts, in heat spreaders in the area of thermal management, as electrode material or for current collectors in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
Graphite fibers compared to carbon fibers are characterized by their high grade of graphitization resulting in the molecular structure and microstructure of graphite. The microstructure of graphite is defined by the crystallographic parameters (i) interlayer spacing (d002 distance) which is the distance between adjacent molecular layers of covalently bonded sp2-hybridized carbon and (ii) mean crystallite size (Lc) which is a measure of the extension of the perfect graphite structure within a material. In a perfect graphite single crystal the d002 distance is 0.3354 nm and Lc corresponds to the size of the macroscopic crystal. While the d002 distance of a carbon fiber which is based on polyacrylonitrile is about 0.345 nm and Lc is about 3 nm after carbonization at 1400°C, one can talk about a graphite fiber, if the d002 distance is 0.344 or lower accompanied with an increase of Lc to 12 nm or higher.
Graphite fibers feature high electrical and thermal conductivity rather than, for example, high tensile strength as carbon fibers do. Thus, the focus of graphite fibers lies on applications requiring suitable thermo-electrical properties rather than good mechanical properties. Graphite fibers can, for example, be obtained by
graphitization of mesophase pitch-based carbon fibers. That means, carbon fibers
based on mesophase pitch are heated to a sufficiently high temperature, typically above 2,200°C, so that the apriori amorphous carbon converts into a graphitic structure. Mesophase pitch-based carbon fibers, however, are very expensive.
Compared to typical polyacrylonitrile-based carbon fibers mesophase pitch-based carbon fibers cost about 100 times more. Polyacrylonitrile-based carbon fibers, however, do not graphitize as good as mesophase pitch-based carbon fibers even if they are heated up to 2,200°C or above.
The d002 distance and the Lc of a polyacrylonitrile-based carbon fiber which is carbonized at a temperature of 2,500°C are about 0.343 nm and 5 nm respectively (Sources: M. Inagaki, F. Kang, Materials Science and Engineering of Carbon:
Fundamentals, Elsevier, 2nd Edition, 2014 and M.R. Buchmeister et al.,
Carbonfasern: Prakursor-Systeme, Verarbeitung, Struktur und Eigenschaften, Angewandte Chemie 2014, vol. 126, pages 5364-5403). In JP2014167039 (A) a catalytic graphitization method is described, wherein the activation energy of the carbonization reaction can be lowered so that the respective carbon fiber carbonized at lower temperatures has the same crystallinity as a typical polyacrylonitrile-based carbon fiber carbonized at higher temperatures. However, carbon fibers having a higher grade of crystallinity are not described. The method includes a copolymeri- zation of polyacrylonitrile with an organometallic compound of a group VIII metal. The so obtained copolymer is then used as a precursor polymer in the known carbon fiber production method. While the performance of a copolymerization method with an organometallic compound is a rather expensive method and the reached crystallinity of the resulting carbon fiber still not exceeds that of typical
polyacrylonitrile-based carbon fibers, better solution should become available.
It is, therefore, the object of the present invention to provide a graphite fiber with a high grade of graphitization which can be manufactured by a simple and cost efficient method.
The solution of the present invention solving this object is based on the finding that solid fine milled particles can be employed in the polyacrylonitrile precursor composition as graphitization catalysts. From such a composition precursor fibers
can be spun which in turn can be further processed to stable graphite fibers having a higher grade of graphitization than typical polyacrylonitrile-based carbon fibers without graphitization catalysts processed under the same conditions. As a first aspect, the present invention provides a polyacrylonitrile-based graphite fiber, wherein the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.344 nm, preferably below 0.341 nm and a mean crystallite size (Lc) of at least 12 nm, preferably at least 20 nm. One of the advantages of the graphite fiber of the present invention is that it has a high thermal conductivity of about 1 100 W/m-K. The electrical conductivity is also very high compared to standard carbon fibers. Furthermore, the graphite fiber of the present invention is less cost-intensive than mesophase-pitch based graphite fibers, since it is based on polyacrylonitrile.
The term "polyacrylonitrile-based" means that the graphite fiber is obtained by starting with polyacrylonitrile as the base material for the respective precursor fiber as it is analogously the case with polyacrylonitrile-based carbon fibers which are well known in the art. The term "polyacrylonitrile-based" also includes co-polymers of polyacrylonitrile with other monomers.
The interlayer spacing (d002 distance) and mean crystallite size (Lc) are
crystallographic standard parameters which can be easily measured by known methods, like X-ray diffraction, for example, according to the method described by J. Maire and J. Mehring in "Graphitization of soft carbons" in Chemistry and Physics of Carbon, Vol. 6, Marcel Dekker, P.L. Walker Jr. (Publisher), New York, 1970, pages 125-190.
The graphite fiber of the present invention is not limited with regard to any coatings or the like being present, for example, on the surface of the fiber. Any such additional material is not encompassed by the expression "the material of the graphite fiber". The "material of the graphite fiber" rather refers to the graphitic material based on polyacrylonitrile.
According to a preferred embodiment of the present invention the material of the polyacrylonitrile-based graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.341 nm, preferably below 0.339 nm after being heated to a temperature of at least 2,500°C for 30 minutes. Even more preferably, the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.339 nm, preferably below 0.337 nm after being heated to a temperature of at least 3,000°C for 30 minutes. The material of the fiber is, thus, getting close to the ideal graphite structure featuring high thermal and electrical conductivity. Furthermore, also the frictional properties are advantageous, in particular for applications like as friction materials in clutches, wet-friction, brake discs and brake pads.
According to a preferred embodiment of the present invention the material of the polyacrylonitrile-based graphite fiber exhibits a mean crystallite size (Lc) of at least 12 nm, preferably at least 20 nm after being heated to a temperature of at least 2,500°C for 30 minutes. Even more preferably, the material of the graphite fiber exhibits a mean crystallite size (Lc) of at least 20 nm, preferably at least 30 nm after being heated to a temperature of at least 3,000°C for 30 minutes. This high grade of crystallinity also leads to high thermal and electrical conductivity and advantageous frictional properties.
The polyacrylonitrile-based graphite fiber according to the present invention is not limited with regard to any other ingredients within the fiber besides the graphitic polyacrylonitrile-based material. In a preferred embodiment, however, the graphite fiber contains one or more elements selected from the group consisting of Ca, Ti, Si, B, V, Cr, Ni, Mn, Fe, W and Cu in the form of its carbides, oxides, borides and/or nitrides, wherein the carbides, oxides, borides or nitrides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 μιτι, preferably 10 nm to 0.35 μιτι and more preferably 50 nm to 0.1 μιτι. In the graphite fiber, such particles may have some advantageous functions depending on the final application of the fiber. In the context of the present invention, the mean particle size corresponds to the d50-value. This particle size can be measured by using the laser diffraction method according to ISO 13320. The main function of these particles lies in the catalysis of the graphitization reaction which leads to the high grade of
crystallinity according to the present invention of the material of the graphite fiber. More preferably, the graphite fiber comprises one or more elements selected from the group consisting of Ti, Si and Ni in the form of its carbides and/or oxides, wherein the carbides or oxides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 μιτι, preferably 10 nm to 0.35 μιτι and more preferably 50 nm to 0.1 μιτι.
According to a still further preferred embodiment of the present invention the particles are present in an amount of 0.01 to 3 weight-percent (wt.-%), preferably of 0.01 to 1 .5 wt-%, based on the total weight of the graphite fiber. Within these ranges the highest grades of graphitization can be observed. The amount can be measured simply by burning the graphite fiber in an oxygen-containing atmosphere, weighing the residual ashes and analyzing the ashes. The total ash content of the graphite fiber of the present invention is not particularly limited. Preferably, however, the graphite fiber has an ash content in the range 0.01 to 3 wt-%, preferably of 0.01 to 1 .5 wt-%, based on the total weight of the graphite fiber, wherein at least 60% the ash consists of NiC, NiO, TiC, T1O2, SiC, S1O2 or mixtures thereof.
In another embodiment of the present invention the graphite fiber has an ash content of below 0.1 wt-%, preferably below 0.05 wt-% and more preferably below 0.01 wt-% based on the total weight of the graphite fiber and that the fiber is porous and contains voids having a mean diameter in the range of 5 nm to 1 μιτι. Such a fiber can be obtained according to a preferred method described below, wherein the graphite fiber is subjected to a purification method, for example, with chlorine gas converting the particles mentioned above into volatile substances and, thus, removing them from the fiber. As a result, the preferred graphite fiber of the present invention is of high purity and high crystallinity. The residual pores resulting from the particles previously present in the graphite fiber preferably have mean diameter in the range of 5 nm to 1 μιτι, preferably 10 nm to 0.35 μιτι and more preferably 50 nm to 0.1 μιτι. It is assumed that the particles mentioned above are completely removed during the purification process leaving pores having the corresponding size of the particles. The pore volume of such a purified fiber is preferably in the range of 0.005 Vol.-% to 1 .5 Vol.-%.
The polyacrylonitrile-based graphite fiber of the present invention can be further processed into any textile. In another aspect, the present invention relates to a textile fabric comprising the polyacrylonitrile-based graphite fiber of the present invention being in the form of a woven fabric, a nonwoven or a paper. These textiles can be advantageously used as battery felts used in redox-flow batteries or NaS batteries, for carbon fiber papers used as gas diffusion layers in fuel cells and electrolysis cells, in satellite structure parts, in heat spreaders in the area of thermal
management, as electrode material or for current collectors in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
In another aspect, the present invention relates to a method for the manufacture of a graphite fiber comprising the following steps:
a) providing a liquid polymer comprising polyacrylonitrile,
b) adding carbide, oxide, boride or nitride particles of one or more elements selected from the group consisting of Ca, Ti, Si, B, V, Cr, Ni, Mn, Fe, W and Cu to the liquid polymer, mixing the same and obtaining a precursor composition for the graphite fiber,
c) spinning the precursor composition in order to obtain a precursor fiber,
d) subjecting the precursor fiber to stabilization in order to obtain a stabilized precursor fiber,
e) subjecting the stabilized precursor fiber to carbonization in order to obtain a carbon fiber and
f) subjecting the carbon fiber to graphitization in order to obtain the graphite fiber.
Preferably, the graphite fiber of the present invention is manufactured by the method of the present invention.
The term "liquid polymer comprising polyacrylonitrile" in the context of the present invention encompasses any liquid, including but not limited to solutions or melts, containing any polyacrylonitrile-containing polymer, including but not limited to a polyacrylonitrile polymer, a copolymer with polyacrylonitrile. Any known
polyacrylonitrile-based precursor compositions for carbon fiber production can be used as the liquid polymer.
The particles added in step b) work as graphitization catalysts in the later
graphitization step f), resulting in a graphite fiber of a high grade of graphitization. Preferably, the particles added in step b) comprise carbide or oxide particles of Ti, Si or Ni and the particles have a mean particle size in the range of 5 nm to 1 μιτι, preferably in the range of 10 nm to 0.35 μιτι and more preferably in the range of 50 nm to 0.1 μιτι. Most preferred are T1O2 and SiC particles having the respective particle size. The preferred particles, in particular, show a high catalytic effect.
Foreign particles in a precursor composition for carbon fibers or graphite fibers always lead to a weakening of the mechanical properties, like tensile strength, of the final fibers. The preferred particle sizes, however, lead to a low weakening of the mechanical properties. As a preferred embodiment of the method of the present invention the particles are added in an amount of 0.05 to 1 .5 wt.-%, more preferably 0.1 to 1 wt.-% based on the total weight of the liquid polymer provided in step a). If the liquid polymer is a solution, then the amount of added particles refers to the proportion of polymer present in the solution. It has been surprisingly found that the grade of graphitization is even higher, if less catalyst is used, for example, using 0.6 wt.-% of T1O2 leads to a higher grade of graphitization than using 1 .5 wt.-% or more. This will be described further below in the examples.
The kind of spinning method in step c) is not particularly limited. Possible spinning methods are air gap spinning, dry spinning, melt spinning and wet spinning.
Preferably, however, the spinning step c) is a wet spinning method, in particular solvent spinning, or air gap spinning. The wet spinning and air gap spinning method are known in the art of polyacrylonitrile-based carbon fiber production.
The graphite fiber of the present invention can be further treated by various methods. Preferably, however, after step f) the graphite fiber is thermally treated at above 1000°C in the presence of chlorine gas or chlorofluorocarbon gas. This treatment leads to a leach out of the particles added in step b) and, thus, to a purification of the graphite fiber. Preferred chlorofluorocarbon gases are dichlorodifluoromethane and 1 ,1 ,1 ,2-tetrafluorethane.
In another aspect, the present invention relates to a method for the manufacture of a textile fabric incorporating the method for the manufacture of a graphite fiber according to the present invention wherein additionally a textile fabric forming process step is performed either with the precursor fiber before step d), with the stabilized precursor fiber before step e), with the carbon fiber before step f) or with the graphite fiber after step f) and that the textile fabric forming process step is one of a woven fabric forming process step, a nonwoven forming process step or a paper forming process step.
If the textile forming process step is performed with the graphite fiber after step f), then the above described preferred purification step can be performed before or after the textile forming process step.
In another aspect, the present invention relates to the use of the graphite fiber according to the present invention as conductive filler for polymers or as additive for friction materials. For this use, the fibers are preferably cut into a suitable length before use.
In another aspect, the present invention relates to the use of the textile fabric according to the present invention as an electrode material or a current collector in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, as a gas diffusion layer in electrolysis or in fuel cells, as a catalyst carrier, as a friction material, preferably in the form of a composite material, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably
for clutches or as a heat spreader in the area of thermal management, in particular for the distribution of heat.
Brief description of the drawings:
Figure 1 : A diagram showing the differences in d002 distance between mesophase pitch based carbon fibers and PAN-based carbon fibers in dependence on the temperature. (Source: M. Inagaki, F. Kang, Materials Science and Engineering of Carbon: Fundamentals, Elsevier, 2nd Edition, 2014)
Figure 2: A diagram showing the differences in crystallite size (Lc) between mesophase pitch and PAN in dependence on the temperature. (Source: M.R.
Buchmeister et al., Carbonfasern: Prakursor-Systeme, Verarbeitung, Struktur und Eigenschaften, Angewandte Chemie 2014, vol. 126, pages 5364-5403)
Figure 3: A diagram showing measurement results. Examples
Four batches of a standard polyacrylonitrile solution for carbon fiber production have been prepared. ΤΊΟ2 powder has been milled until the mean particle size reached the value of d50 = 70 nm. Then the T1O2 powder was mixed in the batches according to the following recipes (the following relative amounts are based on the weight of polyacrylonitrile polymer present in the solution of each of the batches):
Batch no. 1 : 0.35 weight-% of TiO2
Batch no. 2: 0.6 weight-% of TiO2
Batch no. 3: 1 .5 weight-% of TiO2
Batch no. 4: no ΤΊΟ2 was added.
With each of the batches polyacrylonitrile fibers have been spun to precursor fibers by a solvent-spinning method. The respective precursor fibers were further processed by a stabilization process which is heating the precursor fiber under tension in the presence of oxygen, followed by a carbonization step in which the fiber is heated up to 1400°C in the absence of oxygen. The method steps of solvent-
spinning, stabilization and carbonization are well known methods in the field of carbon fiber production.
All four carbon fibers have been finally heated up to 2800°C and the temperature was held at 2800°C for 30 minutes. After cooling, crystallographic measurements were carried out on the resulting carbon or graphite fibers, respectively, which are given in figure 3.
For comparative purposes, mesophase pitch fibers have been heated as well up to 2800°C for 30 minutes. The crystallographic results are as well given in figure 3.
It can be clearly derived form figure 3 that catalytic graphitization takes place in all batches 1 -3. Surprisingly, while the graphite fiber obtained from batch no. 3 (1 .5 weight-% ΤΊΟ2) exhibits nearly the same values of d002 distance and crystallite size Lc as mesophase pitch fiber after heating at 2800°C does, the grade of graphitization is even higher when fewer catalyst particles are employed. The graphite fiber of batch no.1 has a d002 distance of about 0.337 nm and crystallite size Lc of about 70 nm. When looking at figure 1 it is well obvious that such good graphitization values cannot be reached only by heating typical PAN-based carbon fibers without catalyst.
Claims
A polyacrylonitrile-based graphite fiber, characterized in that the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.344 nm.
The polyacrylonitrile-based graphite fiber according to claim 1 , characterized in that the material of the graphite fiber exhibits an interlayer spacing (d002 distance) of below 0.339 nm after being heated to a temperature of at least 3000°C for 30 minutes.
The polyacrylonitrile-based graphite fiber according to claim 1 , characterized in that the material of the graphite fiber exhibits a mean crystallite size (Lc) of at least 20 nm after being heated to a temperature of at least 3000°C for 30 minutes.
The polyacrylonitrile-based graphite fiber according to claim 1 , characterized in that the graphite fiber comprises one or more elements selected from the group consisting of Ca, Ti, Si, B, V, Cr, Ni, Mn, Fe, W and Cu in the form of its carbides, oxides, borides and/or nitrides, wherein the carbides, oxides, borides or nitrides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 μιτι.
The polyacrylonitrile-based graphite fiber according to claim 1 , characterized in that the graphite fiber comprises one or more elements selected from the group consisting of Ti, Si and Ni in the form of its carbides and/or oxides, wherein the carbides or oxides are embedded in the fiber in the form of particles having a mean particle size in the range of 5 nm to 1 μιτι.
The polyacrylonitrile-based graphite fiber according to claim 5, characterized in that the particles are present in an amount of 0.01 to 3 wt.-% based on the total weight of the graphite fiber.
The polyacrylonitrile-based graphite fiber according to claim 5, characterized in that the graphite fiber has an ash content in the range of 0.01 to 3 wt.-% based on the total weight of the graphite fiber, wherein at least 60 % of the ash consists of NiC, NiO, TiC, TiO2, SiC, SiO2 or mixtures thereof.
The polyacrylonitrile-based graphite fiber according to claim 1 , characterized in the graphite fiber has an ash content of below 0.1 wt.-% based on the total weight of the graphite fiber and that the fiber is porous and contains voids having a mean diameter in the range of 5 nm to 1 μιτι.
A textile fabric comprising the polyacrylonitrile-based graphite fiber according to claim 1 being in the form of a woven fabric, a nonwoven or a paper.
A method for the manufacture of a graphite fiber comprising the following steps:
a) providing a liquid polymer comprising polyacrylonitrile,
b) adding carbide, oxide, boride or nitride particles of one or more elements selected from the group consisting of Ti, Si, B, V, Cr, Ni, Mn, Fe, W and Cu to the liquid polymer, mixing the same and obtaining a precursor composition for the graphite fiber,
c) spinning the precursor composition in order to obtain a precursor fiber, d) subjecting the precursor fiber to stabilization in order to obtain a stabilized precursor fiber,
e) subjecting the stabilized precursor fiber to carbonization in order to obtain a carbon fiber and
f) subjecting the carbon fiber to graphitization in order to obtain the graphite fiber.
1 1 . The method of claim 10, characterized in that the particles added in step b) comprise carbide or oxide particles of Ti, Si or Ni and that the particles have a mean particle size in the range of 5 nm to 1 μιτι.
12. The method of claim 10, characterized in that after step f) the graphite fiber is thermally treated at above 1000 °C in the presence of chlorine gas or chlorofluorocarbon gas.
13. A method for the manufacture of a textile fabric comprising the method of claim 10, characterized in that a textile fabric forming process step is performed either with the precursor fiber before step d), with the stabilized precursor fiber before step e), with the carbon fiber before step f) or with the graphite fiber after step f) and that the textile fabric forming process step is one of a woven fabric forming process step, a nonwoven forming process step or a paper forming process step.
14. Use of the graphite fiber according to claim 1 as a conductive filler for
polymers or as additive for friction materials.
Use of the textile fabric according to claim 9, as battery felts used in redox-flow batteries or NaS batteries, for carbon fiber papers used as gas diffusion layers in fuel cells and electrolysis cells, in satellite structure parts, in heat spreaders in the area of thermal management, as electrode material or for current collectors in desalination units, batteries, preferably redox-flow batteries, LiS batteries and Li-ion batteries, preferably as anode material in lithium-ion battery applications, as conductive filler for polymers, as a catalyst carrier, as additive for friction materials, preferably in brake pads or brake discs typically for aircraft and racing cars, wet friction, preferably for clutches, and for deicing applications, as filter material, for electromagnetic shielding, for flash protection and as material for electrical contacts.
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| PCT/EP2017/058695 WO2017178492A1 (en) | 2016-04-11 | 2017-04-11 | Polyacrylonitrile-based graphite fiber |
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| EP3558867A1 (en) | 2016-12-23 | 2019-10-30 | SGL Carbon SE | Graphite material |
| CN110656403B (en) * | 2019-11-07 | 2022-04-05 | 武汉纺织大学 | Easily-conductive metal-doped polyacrylonitrile carbon fiber and preparation method thereof |
| CN110819064B (en) * | 2019-12-03 | 2022-05-20 | 株洲时代新材料科技股份有限公司 | High-thermal-conductivity wear-resistant self-lubricating liner and preparation method thereof |
| CN113417033B (en) * | 2021-06-09 | 2022-10-14 | 山西钢科碳材料有限公司 | Polyacrylonitrile-based fiber, polyacrylonitrile-based carbon fiber and preparation method |
| CN113373554B (en) * | 2021-06-09 | 2022-10-14 | 山西钢科碳材料有限公司 | Low-ash polyacrylonitrile-based fiber, polyacrylonitrile-based carbon fiber and preparation method thereof |
| CN115323825B (en) * | 2022-08-25 | 2023-08-25 | 易高碳材料控股(深圳)有限公司 | Preparation method of high-electric-conductivity and high-heat-conductivity graphite fiber paper |
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| JP4390608B2 (en) * | 2004-03-29 | 2009-12-24 | 帝人株式会社 | Carbon fiber and method for producing the same |
| WO2006101799A2 (en) * | 2005-03-16 | 2006-09-28 | Honeywell International Inc. | Carbon fiber containing ceramic particles |
| JP2014167039A (en) | 2013-02-28 | 2014-09-11 | Toray Ind Inc | Polyacrylonitrile-based polymer, carbon fiber precursor fiber, method for producing the same, and method for producing carbon fiber |
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