CARBON-BASED COMPOSITE MATERIAL, PREPARATION METHOD THEREFOR, AND APPLICATION THEREOF

Abstract

The invention discloses a carbon-based composite material and its preparation method and application, which belongs to the technical field of carbon material preparation. The carbon-based composite material comprises the substrate, carbon film and structural carbon which are integrated into one body. The electron, ion and atom transmission and chemical structure characteristics of the carbon-based composite materials are modified by the carbon film and structural carbon containing alkali and/or alkali earth elements resulting in the carbon-based composite materials having excellent physical and chemical properties, which can be used for various applications including battery electrodes, capacitor electrodes, various sensors, solar cell electrodes, electrolytic water hydrogen production electrodes, hydrogen storage materials, catalysts and catalyst carriers, composite materials, reinforcing materials.

Claims

1. A carbon-based composite material comprising the substrate, carbon film and structural carbon, wherein the carbon film is bonded to the substrate surface and the structural carbon is bonded to the carbon film forming one body; wherein the carbon film and structural carbon both contain alkali and/or alkali earth elements.

2. The carbon-based composite material according to claim 1, wherein the substrate refers to the solid material at room temperature except organic matter, the substrate shape is not limited, the surface area of the substrate ranges from 0.001 square nanometers to 1 billion square meters.

3. The carbon-based composite material according to claim 1, wherein the carbon film comprises carbon and one or more other elements; wherein the content of catalyst alkali and alkali earth metal elements is 0.0000000000001 wt %-99.9999 wt %; wherein the thickness of the carbon film is 0.001 nm-1 mm; wherein the carbon film is continuous or discontinuous covering the substrate.

4. The carbon-based composite material according to claim 1, wherein the structural carbon comprises carbon and one or more other elements; wherein the content of catalyst alkali and alkali earth metal elements is 0.0000000000001 wt %-99.9999 wt %; wherein the structural carbon comprises the carbon containing material with arbitrary shape.

5. A preparation method of carbon-based composite material according to any one of claims 1-4 comprising the following steps: (A1) the catalyst mixture is coated on the substrate surface followed by drying under required conditions; (A2) the substrate loaded with catalyst mixture is placed in a heating furnace with certain atmosphere, followed by heating the heating furnace to a temperature of −50-1500° C. and temperature holding of 0-1000 hours; (A3) the atmosphere in the heating furnace is adjusted to replace the atmosphere in the step (A2), followed by adjusting the heating furnace to the reaction temperature of −50-1500° C. and adjusting the atmosphere in the heating furnace according to the need, then the carbon containing organic matter is inlet into the heating furnace followed by temperature holding of 0-1000 hours; (A4) the heating furnace is turn off and its atmosphere is adjusted as needed to let furnace cool to −50-100° C. to obtain the carbon-based composite material; or includes the following steps: (B1) the catalyst mixture is coated on the substrate surface followed by drying, and then coating the carbon containing organic matter on the substrate to prepare the reactant; or the catalyst mixture is mixed with the substrate followed by mixing with carbon containing organic matter to prepare the reactant; (B2) the reactant is heated in a heating furnace with required atmosphere to a temperature of −50-1500° C. followed by temperature holding of 0-1000 hours; (B3) the heating furnace is turn off to let the furnace cool to −50-100° C. to obtain carbon based composite material.

6. The preparation method of carbon-based composite material according to claim 5, wherein the substrate to be coated in steps (A1) and (B1) is cleaned by various methods followed by drying under appropriate conditions; herein the drying temperature is −50-1000° C., and the drying time is 0-1000 hours; the catalyst mixture is then coated on the substrate by any realizable methods including spraying, dipping, wiping, scraping, brushing, drenching, wiping, roller coating, printing, printing followed by drying in any suitable atmosphere; the catalysts used in steps (A1) and (B1) comprise the simple substance, organic compound and inorganic compound of alkali metals and alkaline earth metals and their mixtures.

7. The preparation method of carbon-based composite materials according to claim 6, wherein the catalyst mixture comprises uniformly dispersed solution, suspension, paste or powder of one or more catalysts.

8. The preparation method of carbon-based composite material according to claim 7, wherein the catalyst mixture can contain the additives, surfactant and thickeners as required; the additives include any compounds for controlling the morphology of structural carbon and preparing the carbon-based composite materials consisting of one type of carbon-based composite material and compound-substrate carbon-based composite material; the mass fraction of additives, surfactant and thickeners in the catalyst mixture is 0-99%; the carbon containing organic matter in steps (A3) and (B1) comprises alcohols, organic acids, alkenes, alkanes, alkynes, ketones, various carbonaceous gases, sugars, various resins and mixtures of the above substances.

9. The carbon-based composite material produced according to claim 1 is used for applications including the electrode materials of capacitor and battery.

Description

DESCRIPTION OF ATTACHED DRAWINGS

[0062] FIG. 1 illustrates a schematic description and scanning electron microscopy (SEM) photos of the carbon nanotube array deposited on Cu substrate using the existing technology.

[0063] FIG. 2 illustrates the SEM morphologies of the in-situ deposited carbon nanotube arrays on copper foil, copper mesh, copper braided mesh using existing technology as binder-free electrode.

[0064] FIG. 3 illustrates the schematic diagram and SEM morphologies of the Si/CNT electrode deposited on stainless steel disc of 15.5 mm in diameter using existing technology.

[0065] FIG. 4 illustrates the schematic diagram of the carbon-based composite material produced in accordance with this disclosure.

[0066] FIG. 5 illustrates the SEM morphologies of the carbon-based composite material produced in example 1 by using stainless steel as substrate and K.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene) (a) magnification 2000, (b) magnification 10000, (c) magnification 50000

[0067] FIG. 6 illustrates the SEM morphologies of the carbon-based composite material produced in example 1 by using stainless steel as substrate and Na.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 2000, (b) magnification 10000, (c) magnification 50000

[0068] FIG. 7 illustrates the SEM morphologies of the carbon-based composite material produced in example 1 by using stainless steel as substrate and Li.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 1000, (b) magnification 2000, (c) magnification 10000

[0069] FIG. 8 illustrates the SEM morphologies of the carbon-based composite material produced in example 1 by using stainless steel as substrate and KF as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 2000, (b) magnification 10000, (c) magnification 50000

[0070] FIG. 9 illustrates (a) TEM photos of carbon film and structural carbon formed into one body using K.sub.2CO.sub.3 catalyst and (b) TEM photos of carbon film and structural carbon formed into one body using Na.sub.2CO.sub.3 catalyst and (c) TEM photos of carbon film and structural carbon formed into one body using Li.sub.2CO.sub.3 catalyst in accordance with this disclosure.

[0071] FIG. 10 illustrates the SEM photos of the carbon-based composite material produced in example 2 by using 8 um copper foil as substrate and Li.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene)

[0072] FIG. 11 illustrates the SEM photos of the carbon-based composite material produced in example 2 by using 8 um Cu foil as substrate and K.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene)

[0073] FIG. 12 illustrates the SEM photos of the carbon-based composite material produced in example 2 by using 20 um aluminium foil as substrate and K.sub.2CO.sub.3 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene)

[0074] FIG. 13 illustrates the SEM photos of the carbon-based composite material produced in example 2 by using Si substrate and Li.sub.2CO.sub.3 catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene)

[0075] FIG. 14 illustrates the SEM photos of the carbon-based composite material produced in example 2 by using silicon substrate and Li.sub.2CO.sub.3/Na.sub.2CO.sub.3/K.sub.2CO.sub.3 (molar mass ratio 1:1:1) catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 2000 TEM

[0076] FIG. 15 illustrates the SEM photos of the carbon-based composite material produced in example 3 by using stainless steel as substrate and NaBr as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 20000, (b) magnification 50000

[0077] FIG. 16 illustrates the SEM photos of the carbon-based composite material produced in example 3 by using stainless steel as substrate and LiH.sub.2PO.sub.4 as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 20000, (b) magnification 50000

[0078] FIG. 17 illustrates the SEM photos of the carbon-based composite produced in example 4 by using silicon as substrate and Na.sub.2CO.sub.3/LiCl (molar mass ratio 1:2) as catalyst in accordance with this disclosure. (650° C., 1 hour, acetylene), (a) magnification 20000, (b) magnification 60000

[0079] FIG. 18 illustrates the SEM photos of the carbon-based composite material produced in example 5 by using Si as substrate and K.sub.2CO.sub.3/Na.sub.2CO.sub.3 (molar mass ratio 1:1) as catalyst in accordance with this disclosure. (650° C., 1 hour, acetylene), (a) magnification 3000, (b) magnification

[0080] FIG. 19 illustrates the SEM photos of the carbon-based composite material produced in example 6 by using Si as substrate and CH.sub.3COONa as catalyst in accordance with this disclosure. (650° C., 1 hour, acetylene), (a) magnification 10000, (b) magnification 50000

[0081] FIG. 20 illustrates the SEM photos of the carbon-based composite material produced in example 6 by using silicon as substrate and C.sub.6H.sub.5O.sub.7Na.sub.3.2H.sub.2O as catalyst in accordance with this disclosure. (650° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 30000

[0082] FIG. 21 illustrates the SEM photos of the carbon-based composite material produced in example 7 by using silica as substrate and KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 (molar mass ratio) as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 1000, (b) magnification 5000

[0083] FIG. 22 illustrates the SEM photos of the carbon-based composite material produced in example 7 by using the silica as substrate and KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 (molar mass ratio) as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 20000

[0084] FIG. 23 illustrates the SEM photos of the carbon-based composite material produced in example 7 by using silica as the substrate and KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:1:8 (molar mass ratio) as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 600, (b) magnification 1000

[0085] FIG. 24 illustrates SEM photos of the carbon-based composite material produced in example 8 by using Si as substrate and KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 (molar mass ratio) as catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) magnification 5000, (b) carbon film and structural carbon formed in one body

[0086] FIG. 25 illustrates SEM photos of the carbon-based composite material produced by using Si substrate and KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 (molar mass ratio) catalyst in example 8 in accordance with this disclosure (600° C., 1 hour, acetylene), (a) magnification 2000, (b) magnification 10000.

[0087] FIG. 26 illustrates the SEM photos of the carbon-based composite material produced by using silicon substrate and KHCO.sub.3:NaHCO.sub.3:LiNO.sub.3=8:1:1 (molar mass ratio) catalyst in example 9 in accordance with this disclosure (650° C., 2 hour, acetylene), (a) magnification 500, (b) cross section view of structural carbon, (c) carbon film and structural carbon formed in one body, (d) carbon film and structural carbon formed in one body.

[0088] FIG. 27 illustrates the SEM photos of the carbon-based composite material produced by using silicon substrate and KHCO.sub.3:NaHCO.sub.3:CsNO.sub.3=8:1:1 (molar mass ratio) catalyst in example 9 in accordance with this disclosure (650° C., 2 hour, acetylene), (a) magnification 5000, (b) magnification 30000.

[0089] FIG. 28 illustrates the SEM photos of the carbon-based composite material produced by using 8 um Cu foil as substrate and CaCl.sub.2 as catalyst in example 10 in accordance with this disclosure (600° C., 1 hour, acetylene), (a) magnification 1000, (b) magnification 3000.

[0090] FIG. 29 illustrates the SEM photos of the carbon-based composite material produced by using 8 um Cu foil and 50 um stainless-steel foil as the substrate and K.sub.2CO.sub.3 as catalyst in example 11 in accordance with this disclosure. (630° C., 1 hour, methane), (a) stainless steel substrate, magnification 10000, (b) stainless steel substrate, magnification 80000. (c) Cu substrate, magnification 1000, (d) Cu substrate, magnification 6000.

[0091] FIG. 30 illustrates the SEM photos of the carbon-based composite material produced by using the 8 um copper foil and 50 um stainless steel foil as substrates, and LiCl/Fe(NO.sub.3).sub.3 and LiH.sub.2PO.sub.4/Fe(NO.sub.3).sub.3 as catalysts in example 12 in accordance with this disclosure. (600° C., 1 hour, acetylene), (a) Cu substrate and LiCl/Fe(NO.sub.3).sub.3 catalyst, magnification 10000, (b) Cu substrate and LiCl/Fe(NO.sub.3).sub.3 catalyst, magnification 100000, (c) stainless steel substrate and LiH.sub.2PO.sub.4/Fe(NO.sub.3).sub.3 catalyst, magnification 10000, (d) stainless steel substrate and LiH.sub.2PO.sub.4/Fe(NO.sub.3).sub.3 catalyst, magnification 100000.

[0092] FIG. 31 illustrates the SEM photos of the carbon-based composite material produced by using 8 um copper foil as substrate and MgCl.sub.2 as catalyst in example 13 in accordance with this disclosure. (550° C., 1 hour, acetylene), (a) magnification 2000, (b) magnification 5000

[0093] FIG. 32 illustrates the SEM photos of the carbon-based composite material produced in example 14 by using 20 um nickel foil as the substrate and MgCl.sub.2 as the catalyst in accordance with this disclosure. (530° C., 1 hour, toluene), (a) magnification 10000, (b) magnification 30000

[0094] FIG. 33 illustrates the SEM photos of the carbon-based composite material produced in example 15 by using 20 um nickel foil as substrate, and MgCl.sub.2/CaCl.sub.2 (mass ratio 1:1) as catalyst in accordance with this disclosure. (530° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 20000, (c) TEM, magnification 4000, (d) TEM, magnification 4000

[0095] FIG. 34 illustrates the SEM photos of the carbon-based composite material produced in example 16 by using 20 um nickel foil as substrate, and Ba(NO.sub.3).sub.3 as catalyst in accordance with this disclosure. (530° C., 1 hour, toluene), (a) magnification 10000, (b) magnification 30000

[0096] FIG. 35 illustrates the SEM photos of the carbon-based composite material produced in example 17 by using 8 um copper foil as substrate and Ba(NO.sub.3).sub.3/LiCl/FeCl.sub.3 (mass molar ratio 1:10:0.1) as catalyst mixture and AlPO.sub.4 as additive in accordance with this disclosure. (550° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 10000

[0097] FIG. 36 illustrates the SEM photos of the carbon-based composite material produced in example 18 by using graphite paper as substrate and Ba(NO.sub.3).sub.3/LiCl/FeCl.sub.3 (mass molar ratio 1:10:0.1) as catalyst mixture in accordance with this disclosure. (550° C., 1 hour, acetylene), (a) magnification 5000, (b) magnification 10000

[0098] FIG. 37 illustrates the SEM photos of the carbon-based composite material produced in example 19 by using 8 um copper foil as substrate and Ba(NO.sub.3).sub.3/LiCl/FeCl.sub.3 (mass molar ratio 1:10:0.1) as catalyst mixture in accordance with this disclosure. (550° C., 1 hour, acetylene), (a) magnification 10000, (b) magnification 50000

[0099] FIG. 38 illustrates the SEM photos of the carbon-based composite material produced in example 20 by using titanium foil as substrate and LiCl as catalyst in accordance with this disclosure. (550° C., 1 hour, acetylene), (a) magnification 10000, (b) magnification 50000

[0100] FIG. 39 illustrates the SEM and TEM photos of the carbon-based composite material produced in example 21 by using CoO as substrate, LiCl/FeCl.sub.3 as catalyst mixture in accordance with this disclosure. (600° C., 1 hour, polypropylene), (a) magnification 10000, (b) magnification 50000, (c)TEM magnification 8000, (d) TEM magnification 80000

[0101] FIG. 40 illustrates the SEM and TEM photos of the carbon-based composite material produced in example 22 by using Al.sub.2O.sub.3 as substrate, LiCl/FeCl.sub.3 as catalyst mixture in accordance with this disclosure. (600° C., 1 hour, vegetable oil), (a) magnification 2000, (b) magnification 10000, (c)TEM magnification 20000, (d) TEM magnification 250000

[0102] FIG. 41 illustrates the SEM photos of the carbon-based composite material produced in example 23 by using Al.sub.2O.sub.3 as substrate and yyy as catalyst mixture in accordance with this disclosure. (500° C., 1 hour, acetylene)), (a) magnification 5000, (b) magnification 20000 LiCl/CuCl2/Ni(CH.sub.3COO).sub.2

[0103] FIG. 42 illustrates the SEM photos of the carbon-based composite material produced in example 24 by using CaCO.sub.3 as substrate and catalyst in accordance with this disclosure. (600° C., 1 hour, acetylene)), (a) magnification 2000, (b) magnification 50000

[0104] FIG. 43 illustrates the charge and discharge curves of the cell assembled by using (a) lithium foil and (b) composite material as the anodes and LiFePO.sub.4 as the cathode.

DETAILED EXAMPLE DESCRIPTIONS

[0105] The examples described below aims to further explain the content of the invention, but not to limit the claim extent.

[0106] The examples described below aims to explain the method diversity of producing the carbon-based composite material in accordance with this disclosure.

[0107] The examples described below aims to show the morphological diversity of the carbon-based composite material produced in accordance with this disclosure.

[0108] Examples described below aims to show the substrate, carbon film and structural carbon formed in one body of composite produced in accordance with this disclosure.

[0109] Examples described below aims to show the application of the carbon-based composite material produced in accordance with this disclosure as the anode of lithium-ion battery.

Example 1

[0110] The composite material is produced by the method as described below. 1 gram of K.sub.2CO.sub.3 and Li.sub.2CO.sub.3 and KF were separately dissolved into 20 g deionized water with 1% surfactant to prepare the catalyst solution. Then, the stainless-steel foil was coated by catalyst by spraying followed by drying in an oven at 80° C. The catalyst coated stainless steel foil was then put into the tube furnace, followed by vacuuming the furnace and injecting the Ar gas. The furnace was then heated to 600° C. at a rate of 10° C./min, followed by temperature dwell for 30 min. Then, acetylene gas was inlet into the furnace at a flow rate of 100 ml/min, followed by temperature dwell at 600° C. for 1 hour. Then, the furnace was turn off followed by inletting the Ar gas into the furnace to let the furnace cool down at 10° C./min to room temperature to get the composite materials.

[0111] SEM (Jeol-6700) was used to examine the morphology of as fabricated composite material and the results are shown in FIG. 5. The composite material fabricated by using K.sub.2CO.sub.3 catalyst has a structural carbon of well aligned carbon nanotube array with a fiber diameter between 100 to 200 nm. The composite material fabricated by using Na.sub.2CO.sub.3 catalyst has a structural carbon of well aligned carbon nanotube array with a uniform fiber diameter of about 150 nm, as shown in FIG. 6. The composite material fabricated by using Li.sub.2CO.sub.3 catalyst has a structural carbon of intertwined carbon nanotube with a fiber diameter and length of about 150 nm and 30 um, accordingly, as shown in FIG. 7. The composite material fabricated by using KF catalyst has a structural carbon of well aligned, but slightly bended and thin-top carbon nanotube array with a fiber diameter of about 100 nm, as shown in FIG. 8. The carbon film and structural carbon are scratched away from the substrate surface using razor blade, followed by examination using

[0112] TEM. FIG. 9 shows clearly that the structural carbon is consisted of carbon nanotube, which is attached to the carbon film forming into one body.

Example 2

[0113] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0114] 1 g of K.sub.2CO.sub.3) and Li.sub.2CO.sub.3 were dissolved into 20 g of deionized water to prepare the catalyst solution. Then, the catalyst solution was sprayed on 8 micron thick copper foil, 20 micron thick aluminum foil and silicon wafer respectively, followed by drying them in a drying oven at 80° C. 0.3 g of K.sub.2CO.sub.3, 0.3 g of Li.sub.2CO.sub.3 and 0.3 g of Na.sub.2CO.sub.3 were dissolved into 20 g of deionized water to prepare the catalyst solution. Then, the catalyst solution was sprayed on the silicon wafer, followed by drying in a drying oven. Subsequently, the dried copper foil, aluminum foil and silicon wafer were placed in the tubular furnace, followed by vacuuming the tubular furnace and inletting argon gas, orderly. Then, the tubular furnace was heated from room temperature to 600° C. at 10° C./min, and then the acetylene gas was introduced into the tubular furnace at 100 ml/min After reacting at 600° C. for 1 hour, the furnace was turn off and argon was introduced into the tubular furnace to let the tubular furnace cool to room temperature at 10° C./min to obtain copper substrate, aluminum substrate and silicon substrate composite materials. The obtained samples were observed by jeol-6700 scanning electron microscope, then. As shown in FIG. 10, the structural carbon of copper substrate composite material prepared by Li.sub.2CO.sub.3 catalyst is mainly spiral carbon fiber array with good orientation, and the fiber diameter is about 100 nm. FIG. 11 shows that the structural carbon of copper substrate composite material prepared by

[0115] K.sub.2CO.sub.3 catalyst is mainly non-oriented and arbitrarily bent fibers with a fiber diameter of about 20 nm. The structural carbon of aluminum substrate composite material prepared by K.sub.2CO.sub.3 catalyst is carbon fibers with orientation and dispersed distribution, as shown in FIG. 12. The structural carbon of silicon substrate composite prepared by Li.sub.2CO.sub.3 catalyst is intertwined slender carbon nanotubes with a fiber diameter of about 20 nm, as shown in FIG. 13. The structural carbon of the silicon substrate composite materials prepared by Li.sub.2CO.sub.3/Na.sub.2CO.sub.3/K.sub.2CO.sub.3 mixed catalyst is a conical carbon nanotube with very good orientation, and the top diameter of the carbon nanotube is about 150 nm, as shown in FIG. 14.

Example 3

[0116] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0117] 1 g of sodium bromide (NaBr) and lithium dihydrogen phosphate (LiH.sub.2PO.sub.4) were dissolved into 20 g of deionized water with 1% surfactant to prepare the catalyst solution. The catalyst solution was then sprayed onto 50 micron thick stainless-steel foil. The coated stainless-steel foil was dried in an 80° C. drying oven followed by placing the sample in a tubular furnace. Then, the tubular furnace was vacuumed and injected argon. The tubular furnace was heated from room temperature to 650° C. at 10° C./min followed by temperature holding of 30 minutes to ensure good contact and reaction between the catalyst and the substrate surface, so that, the thickness of the formed carbon film will be uniform, and the morphology of the formed structural carbon will be uniform. Then, the furnace temperature was reduced to 600° C., and the acetylene gas was introduced into the tubular furnace at 100 ml/min After reacting at 600° C. for 1 hour, argon was introduced into the tubular furnace, and the tubular furnace was cooled at 10° C./min to room temperature to obtain the carbon-based composite material. The morphology of composite material was observed by jeol-6700 scanning electron microscope, as shown in FIG. 15. It can be seen from the figure that the structural carbon of the composite material prepared by NaBr catalyst is a carbon nanotube array with an opening at the top, a uniform thickness and a fiber diameter of about 50 nm. The structural carbon of the composite material prepared by lithium dihydrogen phosphate (LiH.sub.2PO.sub.4) catalyst consists of a clustered carbon fiber array with uniform thickness and diameter of about 5 nm, as shown in FIG. 16.

Example 4

[0118] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0119] 5 g of Na.sub.2CO.sub.3/LiCl (Na.sub.2CO.sub.3:LiCl=1:2 molar ratio) and an appropriate amount of distilled water were ground in a mortar into paste. Then, the paste catalyst is evenly coated on the silicon wafer and dried in the drying oven. The silicon wafer coated with catalyst was placed into the tubular furnace, followed by vacuuming the tubular furnace and injecting argon at a flow rate of 300 ml/min. Then, the furnace was heated to 650° C., followed by temperature dwell for 30 min Then, acetylene was inlet into the furnace at the rate of 200 ml/min for 1 hour followed by cutting off acetylene and injecting argon to prevent oxidation of the example during cooling the furnace to room temperature at 15° C./min. The prepared silicon wafer substrate composites were observed by scanning electron microscope, as shown in FIG. 17.

Example 5

[0120] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0121] In this example, K.sub.2CO.sub.3/Na.sub.2CO.sub.3 (K.sub.2CO.sub.3:Na.sub.2CO.sub.3=1:1, molar ratio) is used as catalyst. The catalyst and appropriate amount of water were ground into paste for use. Then, the paste catalyst was evenly smeared on the silicon wafer followed by drying in the drying oven. The dried silicon wafer was heated in the tubular furnace to 650° C. in air atmosphere at a heating rate of 5° C./min followed by temperature holding time of 100 minutes. Then, argon was inlet into the furnace at a flow rate of 300 ml/min for 10 minutes. Then, acetylene was inlet into furnace for 1 hour at a flow rate of 300 ml/min until the end of the reaction. Then, acetylene was cut off and argon was inlet into furnace as protective gas to prevent oxidization by air at a flow rate of 200 ml/min. When the furnace temperature was below 30° C., Ar gas was turn off and the sample was taken out of the furnace. The morphology of composite material was observed with jeol-6700 scanning electron microscope. As shown in FIG. 18, the structural carbon consists of a curved carbon nanotube with an irregular conical structure at the bottom and a tube diameter of about 200 nm at the top.

Example 6

[0122] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0123] CH3COONa (sodium acetate) and C.sub.6H.sub.5O.sub.7Na.sub.3.2H.sub.2O (sodium citrate) were ground into powder in a mortar. Then, appropriate amount of deionized water was added into the mortar followed by grinding the chemicals into the paste. Then, the paste was applied evenly on the silicon wafer followed by drying in an 80° C. drying oven. After drying, the silicon wafer was placed into the tubular furnace followed by heating to 650° C. and temperature holding of 30 minutes. Then, the argon was inlet into the furnace at a flow rate of 300 ml/min for 10 minutes. Then, the argon was turn off followed by inletting acetylene gas at the rate of 300 ml/min for 1 hour for reaction. Then, the furnace was turned off and the flow of acetylene was cut off. Then, argon was inlet into the furnace at a gas flow rate of 400 ml/min until the furnace temperature was below 30° C. The morphology of the composite material was observed by jeol-6700 scanning electron microscope. When sodium acetate is used as the catalyst, it can be seen that the structural carbon of the composite is a well oriented carbon nanotube array, which is evenly distributed, and the diameter of carbon nanotubes is about 100 nm, as shown in FIG. 19. When sodium citrate is used as the catalyst, as shown in FIG. 20, the structural carbon nanotubes of the composite are poorly oriented, and there is an emitting head on the top of the carbon nanotube. When the sample is enlarged to 30000 times, it can be seen that the carbon nanotubes is about 250 nm in diameter with rough top and burr shape. These burr like carbon structures may be caused by the residue of catalyst on the surface of carbon nanotubes.

Example 7

[0124] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0125] 1 g of KHCO.sub.3/NaHCO.sub.3/Li.sub.2CO.sub.3 (KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 molar ratio), 1 g of KHCO.sub.3/NaHCO.sub.3/Li.sub.2CO.sub.3 (KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 molar ratio) and 1 g of KHCO.sub.3/NaHCO.sub.3/Li.sub.2CO.sub.3 (KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:1:8 molar ratio) were prepared. Then, an appropriate amount of water was added into the prepared chemicals followed by grinding into paste for use. Then, the paste was coated onto the quartz followed by drying in an 80° C. drying oven. Then, the dried quartz sheet was heated in a tubular furnace to 650° C. at 5° C./min, followed by temperature holding of 120 minutes. Then, argon was inlet into the furnace at a flow rate of 300 ml/min for about 10 minutes. In this step, argon gas will take away the air in the tubular furnace. Then, the furnace temperature was reduced to 600° C. followed by introducing acetylene into the furnace at the flow rate of 300 ml/min After keeping the furnace temperature at 600° C. for 2 hours, the acetylene gas was cut off followed by introducing argon as protective gas to prevent oxidization by air at the flow rate of 200 ml/min. The furnace was then cooled to about 30° C. at a rate of 7° C./min Finally, the argon was cut off and the sample was taken out. The morphology of composite material was observed with jeol-6700 scanning electron microscope. As shown in FIG. 21, the structural carbon of composite material prepared by catalyst with a KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 is consisted of non-uniform carbon fibers with many small burr fibers on the surface of some carbon fibers. As shown in FIG. 22, the structural carbon of composite material prepared by the catalyst with a KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 (molar ratio) catalyst system is like cabbage. As shown in FIG. 23, the structural carbon of composite material prepared by KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:1:8 (molar ratio) catalyst system is like chrysanthemum coronarium. The research results show that the proportion of various elements in the catalyst system will greatly affect the morphology of the structural carbon of carbon-based composite material.

Example 8

[0126] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0127] 1 g of mixed catalyst KHCO.sub.3/NaHCO.sub.3/Li.sub.2CO.sub.3 was prepared according to KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 (molar ratio). 1 g of mixed catalyst KHCO.sub.3/NaHCO.sub.3/Li.sub.2CO.sub.3 was prepared according to KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 (molar ratio). Then, this catalyst mixture and an appropriate amount of water were ground into paste for use. Then, the paste was evenly coated on the silicon wafer followed by drying in an 80° C. drying oven. The dried silicon wafer was heated in a tubular furnace to 650° C. in air, with a heating rate of 5° C./min and a holding time of 120 minutes. Then, argon was inlet into the furnace at a flow rate of 300 ml/min for about 10 minutes. In this step, the air in the tubular furnace is fully discharged by argon. Then, the furnace temperature was reduced to 600° C. followed by introducing acetylene to the furnace for 2 hours at a flow rate of 300 ml/min After the reaction, the acetylene gas was cut off, and then argon was introduced to the furnace as a protective gas to prevent oxidization by air at a flow rate of 200 ml/min. The furnace was cooled to below 30° C. at the rate of 7° C./min Then, argon was turned off and the example was taken out. The morphology of composite material was observed by jeol-6700 scanning electron microscope. As shown in FIG. 24, the structural carbon of composite material prepared with KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=1:8:1 (molar ratio) catalyst system consists of conical carbon with good orientation and a small amount of carbon nanotubes. These structural carbon and carbon film form an integrated structure. As shown in FIG. 25, the structural carbon of composites prepared by KHCO.sub.3:NaHCO.sub.3:Li.sub.2CO.sub.3=8:1:1 (molar ratio) catalyst system has leek shape with good orientation.

Example 9

[0128] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0129] 1 g of mixed catalyst with KHCO.sub.3:NaHCO.sub.3:LiNO.sub.3=8:1:1 (molar ratio) and 1 g of mixed catalyst with KHCO.sub.3:NaHCO.sub.3:CsNO.sub.3=8:1:1 (molar ratio) were prepared. Then, these mixed catalysts were added an appropriate amount of water followed by grinding them into paste for use. The paste catalyst was evenly coated on the silicon wafer followed by drying in an 80° C. drying oven. Then, the dried silicon wafer was placed in a tubular furnace followed by heating to 650° C. at a heating rate of 5° C./min After temperature holding for 100 minutes, argon was introduced into the furnace at a flow rate of 300 ml/min for 10 minutes. Then, acetylene was inlet into the furnace for 2 hours at a flow rate of 300 ml/min. After the reaction, the acetylene gas was turned off and the argon was introduced at a flow rate of 200 ml/min as protective gas to prevent oxidation by air. When the furnace temperature was below 30° C., Ar gas was cut off and the sample was taken out. The morphology of composite material was observed by jeol-6700 scanning electron microscope. As shown in FIG. 26, the structural carbon of composite material deposited with KHCO.sub.3:NaHCO.sub.3:LiNO.sub.3=8:1:1 catalyst system is dendritic carbon tubes, which grow on the carbon film forming an integrated structure, and the thickness of the carbon film is about 800 nm. As shown in FIG. 27, the structural carbon of composite material prepared with KHCO.sub.3:NaHCO.sub.3:CsNO.sub.3=8:1:1 (molar ratio) catalyst system is difficult to describe the shape in language. The great difference of the shape of the two composites is due to the difference of one catalyst.

Example 10

[0130] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0131] 2 g CaCl.sub.2) was dissolved into 38 g of deionized water containing 0.1% surfactant TX-100 to prepare a catalyst mixture. Then, the 8 micron thick copper foil was evenly sprayed with the catalyst mixture followed by drying in a dry oven at 80° C. for 20 minutes. Then, the sample was placed in a heating furnace followed by vacuuming the heating furnace and injecting acetylene gas. Then, the furnace was heated from room temperature to 600° C. (heating time 45 minutes) followed by temperature holding of 1 hour. Finally, the power supply was turned off to let the furnace cool naturally to 50° C., and then the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 28. It can be seen from the figure that the structural carbon of the composite material has an irregular steep protrusion with a width of about 1 micron.

Example 11

[0132] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below. 2 g of K.sub.2CO.sub.3 was dissolved into 38 g of deionized water containing 0.1% surfactant TX-100 to prepare a catalyst solution. The catalyst solution was sprayed on 50 micron thick stainless-steel foil and 8 micron thick copper foil, respectively. The stainless-steel foil and copper foil were dried in a dry oven at 80° C. for 20 minutes and then placed in a furnace. After vacuuming the furnace, methane gas was inlet into the furnace. Then, the furnace was heated from room temperature to 630° C. (heating time 45 minutes) followed by temperature holding of 1 hour. Then, the power supply was turn off to let the furnace cool naturally to 50° C., and then the sample was taken out. The morphology of the composite was observed by scanning electron microscope, and the results are shown in FIG. 29. It can be seen from (a) and (b) in FIG. 29 that the structural carbon deposited on stainless steel is formed by relatively uniform 50 nm flakes and particles. It can be seen from (c) and (d) in FIG. 29 that the structural carbon deposited on copper is formed by mutual bonding of strips about 500 nm wide growing in a specific direction.

Example 12

[0133] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0134] 2 g of LiCl and 0.4 g of Fe(NO.sub.3).sub.3 were dissolved into 38 g of deionized water to prepare LiCl/Fe(NO.sub.3).sub.3 catalyst mixture. The mixture was then sprayed onto 8 micron copper foil. 2 g of LiH.sub.2PO.sub.4 and 0.4 g of Fe(NO.sub.3).sub.3 were dissolved into 37.6 g of deionized water to prepare LiH.sub.2PO.sub.4/Fe(NO.sub.3).sub.3 catalyst mixture, which was sprayed onto 50 micron stainless steel foil. Then, the above samples were dried in an 80° C. drying oven for 20 minutes followed by placing the samples in a furnace. After vacuuming the furnace, acetylene gas was inlet into furnace. Then, the furnace was heated to 600° C. (heating time 45 minutes) followed by temperature holding of 1 hour. Then, the furnace was turn off to let it cool to 300° C. followed by vacuuming the furnace. When the furnace temperature was 30° C., the example was taken out for examination. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 30. It can be seen from (a) and (b) in FIG. 30 that the structural carbon of composite deposited by LiCl/Fe(NO.sub.3).sub.3 catalyst system consists of a curved carbon fiber with a diameter of about 50 nm, which is intertwined and bonded with each other. It can be seen from (c) and (d) in FIG. 30 that the carbon structure of composites deposited by LiH.sub.2PO.sub.4/Fe(NO.sub.3).sub.3 catalyst system is consisted of particles with a diameter of about 20 nm which are bonded together forming the main carbon structure with few carbon fibers of about 10 nm in diameter.

Example 13

[0135] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0136] 2 g of MgCl.sub.2 was dissolved into 38 g of deionized water to prepare a catalyst mixture. The 8 micron thick copper foil was evenly sprayed with the catalyst mixture followed by drying in a dry oven at 80° C. for 20 minutes. Then, the sample was placed in the furnace, followed by vacuuming the furnace and injecting acetylene gas. The furnace was heated from room temperature to 500° C. (heating time 45 minutes) and the temperature was hold for 1 hour. Then the power was turn off to let the furnace cool naturally. When the temperature of the furnace was 300° C., the furnace was vacuumed and then cooled continually to 30° C. The sample was then taken out of the furnace. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 31. It can be seen from the figure that the structural carbon of the prepared composite material is mainly composed of better oriented and regular conical structure mixed with a small amount of fibrous carbon.

Example 14

[0137] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0138] 2 g of MgCl.sub.2 was dissolved into 38 g of deionized water to prepare a catalyst mixture. The 20 micron thick nickel foil washed with acetone was evenly sprayed with the catalyst mixture and dried in a dry oven at 80° C. for 20 minutes. Then the sample was placed in the heating furnace followed by vacuuming the furnace and injecting toluene solution. Then, the furnace was heated to 530° C. (heating time 45 minutes) followed by temperature holding of 1 hour. Then, the furnace was turn off to let the furnace cool naturally. When the temperature of the heating furnace was 300° C., the furnace was vacuumed. When the furnace temperature was 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 32. It can be seen from the figure that the structural carbon of the prepared composite material consists of mainly intertwined carbon fibers with a diameter of about 50 nm and a small amount of special-shaped carbon.

Example 15

[0139] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0140] 1 g of MgCl.sub.2 and 1 g of CaCl.sub.2) were dissolved into 38 g of deionized water to prepare a catalyst mixture. The 20 micron thick nickel foil washed with acetone was evenly sprayed with the catalyst mixture followed by drying in vacuum oven at 80° C. for 20 minutes. Then the sample was placed in the heating furnace, followed by vacuuming and injecting acetylene gas. Then the furnace was heated from room temperature to 530° C. (heating time 45 minutes) followed by temperature holding of 1 hour. Then the furnace was turn off to let the furnace cool naturally.

[0141] When the temperature of the heating furnace was 300° C., the furnace was vacuumed. When the furnace temperature was 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 33. As can be seen from (a) and (b) in FIG. 33, the structural carbon of the prepared composite is mainly linear and helical fibers with a diameter of about 100 nm. The electrode was scraped off the copper foil with a blade, and then observed with transmission electron microscope. It can be seen that the structural carbon is connected together through carbon film, as shown in (c) and (d) in FIG.

Example 16

[0142] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0143] 2 g of Ba(NO.sub.3).sub.3 was dissolved into 38 g of deionized water to prepare a catalyst mixture. The 20 micron thick nickel foil washed with acetone was evenly sprayed with the catalyst mixture and dried in a vacuum oven at 80° C. for 20 minutes. Then, the sample was placed in the heating furnace followed by vacuuming the heating furnace and injecting toluene liquid. Then the furnace was heated from room temperature to 530° C. (heating time 45 minutes) followed by temperature holding for 1 hour. Then the furnace was turn off to let the furnace cool naturally.

[0144] When the temperature of the heating furnace was 300° C., the furnace was vacuumed. When the furnace temperature was 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 34. It can be seen from the figure that the structural carbon of the prepared composites consists of a small amount of granular carbon and fibers with a diameter of 30 to 100 nm.

Example 17

[0145] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0146] 2 g of Ba(NO.sub.3).sub.3, 20 g of LiCl and 0.2 g of FeCl3 and 77.8 g of deionized water were mixed to prepare a mixed catalyst solution. 1 g of aluminum phosphate powder was dispersed in 10 g of mixed catalyst solution to prepare a mixed catalyst suspension of catalyst and solid additives. The copper foil was evenly sprayed with mixed catalyst suspension and dried in at 80° C. vacuum drying oven for 20 minutes. Then, the copper foil was placed in the heating furnace followed by vacuuming and inletting acetylene gas. Then, the heating furnace was heated from room temperature to 550° C. followed by temperature holding of 1 hour. Then, the furnace was turn off to cool the heating furnace to 300° C. Then, the furnace was vacuumed. When the furnace temperature was 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 35. It can be seen from the figure that the structural carbon is consisted of mainly short fibrous protrusions and the aluminum phosphate powder that is adhered and wound together by long carbon fibers. The diameter of carbon fiber is 200 nm to 500 nm. This structure ensures the surface conductivity of aluminum phosphate powder and good electrical contact between aluminum phosphate and copper substrate composite.

Example 18

[0147] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0148] 2 g of Ba(NO.sub.3).sub.3, 20 of g LiCl and 0.2 g of FeCl.sub.3 and 77.8 g of deionized water containing 1 wt % of surfactant TX-100 were mixed to prepare a mixed catalyst solution. The graphite paper was evenly sprayed with a thin layer of mixed catalyst solution followed by drying in an 80° C. vacuum oven for 20 minutes. Then, the samples were put into the furnace followed by vacuuming and inletting acetylene gas. Then, the furnace was heated to 550° C. followed by temperature holding for 1 hour. Then the furnace was turn off to let the furnace cool naturally. When the furnace temperature was 300° C., the heating furnace was vacuumed. When the furnace was 30° C., the samples were taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 36. It can be seen from the figure that the structural carbon consists of carbon fibers with a diameter of about 20 nm, which are intertwined with each other.

Example 19

[0149] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0150] 2 g of Ba(NO.sub.3).sub.3, 20 g of LiCl, 0.2 g of FeCl.sub.3 and 77.8 g of deionized water were mixed to prepare a mixed catalyst solution. The copper foil was evenly sprayed with mixed catalyst solution and dried in an 80° C. vacuum drying oven for 20 minutes. Then, the copper foil was placed in the heating furnace followed by vacuuming the heating furnace before passing acetylene gas. The heating furnace was heated from room temperature to 550° C. with a temperature dwell of 1 hour. Then, the furnace was turn off to let it cool naturally. When the temperature of the heating furnace is 300° C., the furnace was vacuumed. When the furnace temperature was 30° C., the samples were taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 37. It can be seen from the figure that the structural carbon consists of a dead tree pile carbon fiber with a diameter of about 1 micron, which is evenly distributed in the intertwined carbon fibers with a diameter of about 20 nm.

Example 20

[0151] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0152] 2 g of LiCl was dissolved into 98 g of deionized water to prepare a 2 wt % catalyst solution. The 100 micron thick titanium foil was evenly sprayed with catalyst solution followed by drying in a 100° C. drying oven for 10 minutes. The samples were then put into the heating furnace followed by vacuuming and inletting acetylene gas. The furnace was then heated to 550° C. with a temperature dwell of 1 hour. Then, the furnace was turn off followed by vacuuming the furnace at 300° C. When the furnace was cooled to 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 38. It can be seen from the figure that the structural carbon consists of granular carbon and very short carbon fibers.

Example 21

[0153] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0154] 2 g of LiCl and 0.2 g of FeCl.sub.3 were dissolved into 38 g of deionized water to prepare the composite catalyst solution. Then, 5 g of CoO powder and 1 g of composite catalyst solution were evenly mixed and dried in a 100° C. drying oven for 20 minutes followed by grinding with an appropriate number of polypropylene particles to prepare the reaction precursor. Then, the reaction precursor was put into the heating furnace followed by vacuuming and introducing nitrogen. The heating furnace was then heated to 600° C. with a temperature dwell of 1 hour. The furnace was then turn off followed by vacuuming at 300° C. When the temperature of the heating furnace was 30° C., the samples were taken out. The morphology of the sample was observed by scanning electron microscope, and the results are shown in FIG. 39. It can be seen from the figure that there are short fibers of about 20 nm in diameter deposited on the surface of CoO particles. The carbon film and structural carbon on the surface of CoO substrate can be seen by transmission electron microscope. The thickness of the carbon film is about 20 nm, and the structural carbon consists of short carbon nanotube and anisotropic carbon, as shown in (c) and (d) in FIG. 39. The experimental results also show that the electrical conductivity between prepared CoO substrate composite materials is very good.

Example 22

[0155] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0156] 2 g of LiCl and 0.2 g of FeCl.sub.3 were dissolved into 38 g of deionized water to prepare the composite catalyst solution. Then, 5 g of Al.sub.2O.sub.3 powder and 1 g of composite catalyst solution were evenly mixed and dried in a 100° C. drying oven for 20 minutes. The dried material was ground into powder followed by mixing with an appropriate amount of unsaturated fatty acid.

[0157] Then, the sample was put into the furnace followed by vacuuming and inletting nitrogen. Then, the furnace was heated to 600° C. followed by temperature holding of 1 hour. Then, the furnace was turn off followed by vacuuming the furnace at 300° C. When the furnace temperature was 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope. The results are shown in (a) and (b) in FIG. 40. The structural carbon of particulate was deposited on Al.sub.2O.sub.3 particles. The samples were observed by transmission electron microscope as shown in (c) and (d) in FIG. 40. The thickness of carbon film on the surface of Al.sub.2O.sub.3 particles is about 15 nm, and the structural carbon consists of irregular protrusions and tubes. The experimental results also show that the prepared Al.sub.2O.sub.3 substrate composite material have good electrical conductivity.

Example 23

[0158] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0159] 1 g of LiCl, 0.2 g of CuCl.sub.2 and 0.2 g of nickel acetate were dissolved into 38 g of deionized water to prepare the composite catalyst solution. Then, 5 g of Al.sub.2O.sub.3 powder and 1 g of composite catalyst solution were evenly mixed and dried in a 100° C. drying oven for 60 minutes. The dried material was ground into powder for use. Then, the samples were put into the heating furnace followed by heating the furnace to 500° C. Then, the furnace was vacuumed followed by inletting acetylene. The furnace temperature was kept at 500° C. for 1 hour followed by turning off the furnace. When the furnace was cooled to 30° C., the sample was taken out. The morphology of the sample was observed by scanning electron microscope. The results are shown in (a) and (b) in FIG. 40. The surface of Al.sub.2O.sub.3 particles is covered with intertwined carbon fibers with a diameter of about 100 nm, and the carbon fibers grow from the carbon film on the surface of Al.sub.2O.sub.3. Al.sub.2O.sub.3 powder was white before reaction and turn grey black after reaction, indicating that the powder surface is coated with a layer of carbon film.

Example 24

[0160] The carbon-based composite materials produced in this example and example 1 have the same structure, and the preparation method is as below.

[0161] In this experiment, the catalyst was prepared by precursor method. Fumaric acid and calcium hydroxide were mixed and stirred at a molar ratio of 1:1. The obtained solution was dried in a drying oven at 60° C. to obtain a white powder. The powder was ground to obtain a catalyst precursor. Then, the catalyst precursor was calcined in air atmosphere at 700° C. for 1 hour to obtain CaCO.sub.3 catalyst. Then, nitrogen was inlet into the tubular furnace to clean off the air in the tubular furnace to prevent explosion. The furnace was cooled to the deposition temperature of 600° C., followed by cutting off nitrogen and inletting acetylene for vacuumed 1 hour. After the reaction, the furnace was turn off followed by cutting off the acetylene gas and inletting a small amount of hydrogen as protective gas to prevent the deposition products from being oxidized by air. When the heating furnace temperature was 80° C., the sample was taken out.

[0162] The sample was then observed with scanning electron microscope, and the result is as shown in FIG. 42. It can be seen from the figure that carbon fibers with a diameter of about 50 nm grow on the surface of CaCO.sub.3, and the carbon fibers are intertwined with each other.

Example 25

[0163] The electrochemical performance of the prepared composite material as the electrode of lithium-ion battery was tested as follows. The composite material produced by using 8 um copper foil as substrate and LiCl as catalyst was cut into a 14 mm diameter disc. LiFePO.sub.4 powder, conductive graphite and PVDF were prepared into slurry at 85:5:10 mass ratio, and then the slurry was coated on the aluminum foil, followed by vacuum drying at 150° C. for 8 hours to obtain LiFePO.sub.4 positive electrode sheet. The button cells (2025) were assembled in argon (H.sub.2O, O.sub.2<1 ppm) glove box by using LiFePO.sub.4 as cathode, copper substrate composite material and lithium metal as anodes and PP film (Celgard 2400) as separator and 1 m LiPF6 (EC/DMC=1:1) as electrolyte. The constant current charge and discharge performances of button cell were tested with constant current charge and discharge tester (Wuhan Land charge discharge tester). The test conditions are 2-4.2 v and current 50 mA/g. The test results are shown in FIG. 43. The experimental results show that the prepared copper substrate composite material as anode has very good electrochemical properties.