JP2010105885A - Method of modifying activated carbon, electrode material for electric double-layer capacitor, electrode for electric double-layer capacitor and electric double-layer capacitor - Google Patents
Method of modifying activated carbon, electrode material for electric double-layer capacitor, electrode for electric double-layer capacitor and electric double-layer capacitor Download PDFInfo
- Publication number
- JP2010105885A JP2010105885A JP2008281686A JP2008281686A JP2010105885A JP 2010105885 A JP2010105885 A JP 2010105885A JP 2008281686 A JP2008281686 A JP 2008281686A JP 2008281686 A JP2008281686 A JP 2008281686A JP 2010105885 A JP2010105885 A JP 2010105885A
- Authority
- JP
- Japan
- Prior art keywords
- activated carbon
- electric double
- layer capacitor
- heat treatment
- electrode
- 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.)
- Granted
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 336
- 239000003990 capacitor Substances 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000007772 electrode material Substances 0.000 title claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 118
- 239000007789 gas Substances 0.000 claims abstract description 18
- 239000012298 atmosphere Substances 0.000 claims abstract description 17
- 239000011261 inert gas Substances 0.000 claims abstract description 17
- 238000002407 reforming Methods 0.000 claims description 19
- 239000003575 carbonaceous material Substances 0.000 claims description 16
- 150000001339 alkali metal compounds Chemical class 0.000 claims description 9
- 230000003213 activating effect Effects 0.000 claims description 5
- 230000002378 acidificating effect Effects 0.000 abstract description 53
- 125000000524 functional group Chemical group 0.000 abstract description 51
- 239000011148 porous material Substances 0.000 abstract description 36
- 230000007774 longterm Effects 0.000 abstract description 9
- 230000006866 deterioration Effects 0.000 abstract description 2
- 230000007423 decrease Effects 0.000 description 29
- 238000004519 manufacturing process Methods 0.000 description 28
- 230000004913 activation Effects 0.000 description 23
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 17
- 239000002994 raw material Substances 0.000 description 17
- 239000012190 activator Substances 0.000 description 10
- 238000009434 installation Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 239000003463 adsorbent Substances 0.000 description 9
- 229910001873 dinitrogen Inorganic materials 0.000 description 9
- -1 sawdust Substances 0.000 description 9
- 238000001179 sorption measurement Methods 0.000 description 8
- 239000003513 alkali Substances 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 238000007600 charging Methods 0.000 description 6
- 239000008151 electrolyte solution Substances 0.000 description 6
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000004904 shortening Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 4
- 239000003814 drug Substances 0.000 description 4
- 229940079593 drug Drugs 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000002715 modification method Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 description 4
- QDRKDTQENPPHOJ-UHFFFAOYSA-N sodium ethoxide Chemical compound [Na+].CC[O-] QDRKDTQENPPHOJ-UHFFFAOYSA-N 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000006230 acetylene black Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000004448 titration Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000004438 BET method Methods 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 239000003929 acidic solution Substances 0.000 description 2
- 239000002156 adsorbate Substances 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 2
- 239000005011 phenolic resin Substances 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- IXHBSOXJLNEOPY-UHFFFAOYSA-N 2'-anilino-6'-(n-ethyl-4-methylanilino)-3'-methylspiro[2-benzofuran-3,9'-xanthene]-1-one Chemical compound C=1C=C(C2(C3=CC=CC=C3C(=O)O2)C2=CC(NC=3C=CC=CC=3)=C(C)C=C2O2)C2=CC=1N(CC)C1=CC=C(C)C=C1 IXHBSOXJLNEOPY-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 235000013162 Cocos nucifera Nutrition 0.000 description 1
- 244000060011 Cocos nucifera Species 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910052936 alkali metal sulfate Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011335 coal coke Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 238000011437 continuous method Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- XEKOWRVHYACXOJ-UHFFFAOYSA-N ethyl acetate Substances CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 229910021469 graphitizable carbon Inorganic materials 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011302 mesophase pitch Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000011331 needle coke Substances 0.000 description 1
- 229910021470 non-graphitizable carbon Inorganic materials 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000003415 peat Substances 0.000 description 1
- 239000002006 petroleum coke Substances 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 150000004714 phosphonium salts Chemical group 0.000 description 1
- 239000006253 pitch coke Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/13—Energy storage using capacitors
Abstract
Description
本発明は、活性炭の改質方法に関するものである。また、本発明は、前記活性炭の改質方法により得られた活性炭を含有する電気二重層キャパシタ用電極材料、電気二重層キャパシタ用電極、および電気二重層キャパシタに関するものである。 The present invention relates to a method for reforming activated carbon. The present invention also relates to an electrode material for an electric double layer capacitor, an electrode for an electric double layer capacitor, and an electric double layer capacitor containing activated carbon obtained by the method for reforming activated carbon.
活性炭、特にアルカリ金属化合物で賦活処理された活性炭には、水酸基やカルボキシル基等の酸性官能基が存在することが知られている。これらの酸性官能基は、活性炭の反応性や濡れ性等の特性に影響を与える。例えば、活性炭が電気二重層キャパシタ用電極材料として使用される場合、活性炭に酸性官能基が存在することにより、静電容量等の電極材料としての特性が長期使用の間に低下しやすくなる。 It is known that activated carbon, particularly activated carbon activated with an alkali metal compound, has acidic functional groups such as hydroxyl groups and carboxyl groups. These acidic functional groups affect properties such as reactivity and wettability of activated carbon. For example, when activated carbon is used as an electrode material for an electric double layer capacitor, the characteristics as an electrode material such as capacitance are likely to deteriorate during long-term use due to the presence of acidic functional groups in the activated carbon.
長期使用による静電容量の低下を緩和する活性炭の改質方法として、賦活処理された活性炭を加熱処理する方法が提案されている。例えば、特許文献１には、アルカリ賦活処理された活性炭を、不活性ガスまたは還元性ガス雰囲気下で９００℃〜１１００℃の温度で加熱処理する方法が開示され、特許文献２には、アルカリ賦活処理された活性炭を、不活性ガス雰囲気下で、昇温速度０．１℃／ｍｉｎ〜１００℃／ｍｉｎ、最高温度５００℃〜１０００℃の温度で加熱処理する方法が開示され、特許文献３には、賦活処理された活性炭を、不活性ガス雰囲気下で７００℃〜１０００℃の温度で加熱処理する方法が開示されている。
特許文献１〜３に開示された方法では、加熱処理により、活性炭に存在する酸性官能基の量が低減され、静電容量の経時劣化を緩和しているものと考えられるが、加熱処理により、同時に活性炭の比表面積や細孔容積の低下が起こる。活性炭の比表面積や細孔容積の低下は、活性炭を電気二重層キャパシタ用電極材料用途に用いた場合の初期静電容量低下をもたらすとともに、活性炭を吸着材として用いる場合の吸着容量の低下も引き起こす。 In the methods disclosed in Patent Documents 1 to 3, it is considered that the amount of acidic functional groups present in the activated carbon is reduced by the heat treatment, and it is considered that the deterioration with time of the capacitance is alleviated. At the same time, the specific surface area and pore volume of the activated carbon are reduced. The decrease in specific surface area and pore volume of activated carbon causes a decrease in initial capacitance when activated carbon is used for electrode materials for electric double layer capacitors, and also causes a decrease in adsorption capacity when activated carbon is used as an adsorbent. .
本発明は上記事情に鑑みてなされたものであり、その目的は、活性炭の比表面積や細孔容積の低下を極力抑えつつ、活性炭に存在する酸性官能基の量を低減できる活性炭の改質方法を提供することにある。また、初期静電容量が高く、長期使用による静電容量の低下が低く抑えられた電気二重層キャパシタ用電極材料、電気二重層キャパシタ用電極、電気二重層キャパシタを提供することにある。 The present invention has been made in view of the above circumstances, and the object thereof is a method for reforming activated carbon capable of reducing the amount of acidic functional groups present in the activated carbon while minimizing the decrease in the specific surface area and pore volume of the activated carbon. Is to provide. Another object of the present invention is to provide an electrode material for an electric double layer capacitor, an electrode for an electric double layer capacitor, and an electric double layer capacitor that have a high initial capacitance and a low decrease in capacitance due to long-term use.
上記課題を解決することができた本発明の活性炭の改質方法とは、活性炭を、不活性ガスまたは還元性ガス雰囲気下、加熱処理する方法であって、前記加熱処理の温度が５００℃〜２０００℃の範囲にあり、前記加熱処理の時間が１０分未満であるところに特徴を有する。本発明の活性炭の改質方法は、前記構成により、比表面積や細孔容積の低下を極力抑えつつ、活性炭に存在する酸性官能基の量を低減することができる。 The method for reforming activated carbon of the present invention that has solved the above problems is a method in which activated carbon is heat-treated in an inert gas or reducing gas atmosphere, and the temperature of the heat treatment is from 500 ° C to 500 ° C. It is in the range of 2000 ° C., and the heat treatment time is less than 10 minutes. The method for reforming activated carbon of the present invention can reduce the amount of acidic functional groups present in the activated carbon while suppressing the decrease in specific surface area and pore volume as much as possible.
前記改質方法において用いる活性炭は、炭素質物質をアルカリ金属化合物で賦活処理して得られたものが好ましい。炭素質物質をアルカリ金属化合物で賦活処理した活性炭を用いれば、改質処理を施しても比表面積や細孔容積が大きい活性炭を得やすくなる。 The activated carbon used in the modification method is preferably obtained by activating a carbonaceous material with an alkali metal compound. If activated carbon obtained by activation treatment of a carbonaceous material with an alkali metal compound is used, activated carbon having a large specific surface area and pore volume can be easily obtained even when the modification treatment is performed.
本発明の改質方法で得られた活性炭は、改質により比表面積や細孔容積の低下が極力抑えられ、活性炭に存在する酸性官能基の量を低減できるため、電気二重層キャパシタの初期静電容量を高くすることができ、長期使用による静電容量の低下も低く抑えることができる。そのため、優れた静電容量特性を有する電気二重層キャパシタ用電極材料、電気二重層キャパシタ用電極、電気二重層キャパシタを得ることができる。 The activated carbon obtained by the modification method of the present invention can suppress the decrease in specific surface area and pore volume as much as possible by modification and can reduce the amount of acidic functional groups present in the activated carbon. Capacitance can be increased, and a decrease in capacitance due to long-term use can be suppressed to a low level. Therefore, an electrode material for an electric double layer capacitor, an electrode for an electric double layer capacitor, and an electric double layer capacitor having excellent capacitance characteristics can be obtained.
本発明の活性炭の改質方法によれば、活性炭の比表面積や細孔容積の低下を極力抑えつつ、活性炭に存在する酸性官能基の量を低減することができる。また、本発明の改質方法により得られる活性炭は、改質により比表面積や細孔容積の低下が極力抑えられ、活性炭に存在する酸性官能基の量を低減できるため、電気二重層キャパシタの初期静電容量を高くすることができ、長期使用による静電容量の低下も低く抑えることができる。そのため、本発明の改質方法により得られる活性炭を含有する電気二重層キャパシタ用電極材料、電気二重層キャパシタ用電極、電気二重層キャパシタは、優れた静電容量特性を有する。 According to the method for reforming activated carbon of the present invention, it is possible to reduce the amount of acidic functional groups present in the activated carbon while suppressing the decrease in the specific surface area and pore volume of the activated carbon as much as possible. In addition, the activated carbon obtained by the modification method of the present invention can suppress the decrease in specific surface area and pore volume as much as possible by modification, and can reduce the amount of acidic functional groups present in the activated carbon. Capacitance can be increased, and a decrease in capacitance due to long-term use can be suppressed. Therefore, the electrode material for electric double layer capacitors, the electrode for electric double layer capacitors, and the electric double layer capacitor containing activated carbon obtained by the modification method of the present invention have excellent capacitance characteristics.
本発明の活性炭の改質方法は、活性炭を、不活性ガスまたは還元性ガス雰囲気下、加熱処理する。 In the method for reforming activated carbon of the present invention, the activated carbon is heat-treated in an inert gas or reducing gas atmosphere.
本発明の活性炭の改質方法において用いられる活性炭は、炭素質物質を賦活処理して得られたものが好ましい。この場合、本発明の改質炭の活性方法は、炭素質物質を賦活処理して活性炭を得る工程、および、前記活性炭を、不活性ガスまたは還元性ガス雰囲気下、加熱処理する工程を有する改質炭の活性方法となる。 The activated carbon used in the method for reforming activated carbon of the present invention is preferably obtained by activating a carbonaceous material. In this case, the modified coal activation method of the present invention includes a step of activating a carbonaceous material to obtain activated carbon, and a step of heat-treating the activated carbon in an inert gas or reducing gas atmosphere. It becomes an active method of peat.
炭素質物質としては、活性炭原料として公知の炭素質物質であれば、特に限定されない。例えば、木材、おが屑、木炭、ヤシガラ、セルロース系繊維、合成樹脂（例えばフェノール樹脂）、石炭等の難黒鉛化性炭素；メソフェーズピッチ、ピッチコークス、石油コークス、石炭コークス、ニードルコークス、ポリ塩化ビニル、ポリイミド、ＰＡＮ等の易黒鉛化性炭素；およびこれらの混合物が挙げられる。炭素質物質は、必要に応じて、賦活処理前に高温炭化処理されていてもよい。 The carbonaceous material is not particularly limited as long as it is a known carbonaceous material as an activated carbon raw material. For example, non-graphitizable carbon such as wood, sawdust, charcoal, coconut shell, cellulosic fiber, synthetic resin (eg phenol resin), coal; mesophase pitch, pitch coke, petroleum coke, coal coke, needle coke, polyvinyl chloride, And graphitizable carbon such as polyimide and PAN; and mixtures thereof. The carbonaceous material may be subjected to high-temperature carbonization treatment before activation treatment as necessary.
賦活処理とは、炭素質物質の表面に細孔を形成して、比表面積および細孔容積を大きくする処理である。この賦活処理としては、（１）賦活剤と炭素質物質との混合物を不活性ガス雰囲気下で加熱して活性炭を製造する薬剤賦活、または（２）水蒸気、二酸化炭素、空気、燃焼ガス等のガスとの共存下、炭素質物質を加熱して活性炭を製造するガス賦活、が知られている。賦活処理としては、活性炭の比表面積を大きくすることが容易な薬剤賦活を採用することが好ましい。 The activation treatment is treatment for forming pores on the surface of the carbonaceous material and increasing the specific surface area and pore volume. As this activation treatment, (1) chemical activation in which activated carbon is produced by heating a mixture of an activator and a carbonaceous substance in an inert gas atmosphere, or (2) water vapor, carbon dioxide, air, combustion gas, etc. Gas activation in which activated carbon is produced by heating a carbonaceous substance in the presence of gas is known. As the activation treatment, it is preferable to employ chemical activation that facilitates increasing the specific surface area of the activated carbon.
薬剤賦活で使用する賦活剤には、アルカリ金属化合物を使用することが好ましい。アルカリ金属化合物を賦活剤として用いることにより、活性炭の比表面積を容易に大きくすることができる。また、アルカリ金属化合物で賦活処理を行って得られる活性炭には、酸性官能基がより多く含まれるようになりやすいため、活性炭に存在する酸性官能基の量を低減するという本発明の効果をより顕著に発現させる点において、本発明で用いられる活性炭は、アルカリ金属化合物で賦活処理（アルカリ賦活処理）をして得られたものが好ましい。 It is preferable to use an alkali metal compound for the activator used in drug activation. By using an alkali metal compound as an activator, the specific surface area of the activated carbon can be easily increased. Moreover, since the activated carbon obtained by performing the activation treatment with the alkali metal compound is likely to contain more acidic functional groups, the effect of the present invention of reducing the amount of acidic functional groups present in the activated carbon is further improved. The activated carbon used in the present invention is preferably obtained by performing an activation treatment (alkali activation treatment) with an alkali metal compound in terms of remarkable expression.
賦活剤として用いられるアルカリ金属化合物としては、アルカリ金属の硫酸塩、炭酸塩、水酸化物等が挙げられ、アルカリ金属水酸化物を用いることが好ましい。アルカリ金属水酸化物としては、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウムが挙げられる。賦活剤の使用量は、アルカリ金属水酸化物を賦活剤として使用する場合、炭素質物質の質量の０．５倍〜１０倍であることが好ましい。この使用量が多量である程、活性炭の比表面積および平均細孔径が大きくなり、少量である程、活性炭の比表面積および平均細孔径が小さくなる。 Examples of the alkali metal compound used as the activator include alkali metal sulfates, carbonates, hydroxides, and the like, and it is preferable to use alkali metal hydroxides. Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, and lithium hydroxide. The amount of the activator used is preferably 0.5 to 10 times the mass of the carbonaceous material when an alkali metal hydroxide is used as the activator. The larger the amount used, the larger the specific surface area and average pore diameter of the activated carbon, and the smaller the amount used, the smaller the specific surface area and average pore diameter of the activated carbon.
薬剤賦活では、炭素質物質および賦活剤とともに水を混合してもよい。水を混合することで、賦活剤を溶融しやすくなる。このときの水の混合量は、アルカリ金属水酸化物を賦活剤に使用する場合、賦活剤の質量の０．０５倍〜１０倍であることが好ましい。 In drug activation, water may be mixed together with the carbonaceous material and the activator. By mixing water, the activator is easily melted. The amount of water mixed at this time is preferably 0.05 to 10 times the mass of the activator when an alkali metal hydroxide is used as the activator.
薬剤賦活における加熱では、加熱温度が４００℃〜９００℃程度であることが好ましい。活性炭の比表面積および平均細孔径は、加熱温度が低いと小さくなる傾向があり、加熱温度が高いと大きくなる傾向がある。 In heating in drug activation, the heating temperature is preferably about 400 ° C to 900 ° C. The specific surface area and average pore diameter of activated carbon tend to decrease when the heating temperature is low, and tend to increase when the heating temperature is high.
薬剤賦活後は、水および／または酸性液により活性炭を洗浄してもよい。水や酸性液による活性炭の洗浄は、公知の方法を採用することができる。また、水および／または酸性液により活性炭を洗浄した後、５００℃未満の温度（好ましくは、５０℃〜３００℃）で活性炭を乾燥してもよい。 After drug activation, the activated carbon may be washed with water and / or an acidic solution. A known method can be employed for washing the activated carbon with water or an acidic liquid. Moreover, after washing | cleaning activated carbon with water and / or an acidic liquid, you may dry activated carbon at the temperature below 500 degreeC (preferably 50 to 300 degreeC).
以上のように、本発明の活性炭の改質方法において用いられる活性炭は、炭素質物質を賦活処理して得られた活性炭が好ましく、炭素質物質をアルカリ賦活処理して得られた活性炭がより好ましい。また、炭素質物質をアルカリ賦活処理して、水および／または酸性液により洗浄して得られた活性炭を用いてもよい。 As described above, the activated carbon used in the method for modifying activated carbon of the present invention is preferably activated carbon obtained by activating a carbonaceous substance, more preferably activated carbon obtained by subjecting a carbonaceous substance to alkali activation. . Further, activated carbon obtained by subjecting a carbonaceous material to alkali activation treatment and washing with water and / or an acidic solution may be used.
本発明で用いられる活性炭の比表面積としては、５００ｍ2／ｇ以上が好ましく、１，０００ｍ2／ｇ以上がより好ましく、２，０００ｍ2／ｇ以上がさらに好ましく、また４，０００ｍ2／ｇ以下が好ましく、３，８００ｍ2／ｇ以下がより好ましく、３，５００ｍ2／ｇ以下がさらに好ましい。 The specific surface area of the activated carbon used in the present invention, 500 meters is preferably at least 2 / g, more preferably at least 1,000 m 2 / g, more preferably not less than 2,000 m 2 / g, also 4,000 m 2 / g or less Is preferably 3,800 m 2 / g or less, more preferably 3,500 m 2 / g or less.
本発明で用いられる活性炭の細孔容積としては、０．１ｍＬ／ｇ以上が好ましく、０．４ｍＬ／ｇ以上がより好ましく、１．０ｍＬ／ｇ以上がさらに好ましく、また３．０ｍＬ／ｇ以下が好ましく、２．５ｍＬ／ｇ以下がより好ましく、２．０ｍＬ／ｇ以下がさらに好ましい。 The pore volume of the activated carbon used in the present invention is preferably 0.1 mL / g or more, more preferably 0.4 mL / g or more, further preferably 1.0 mL / g or more, and 3.0 mL / g or less. Preferably, 2.5 mL / g or less is more preferable, and 2.0 mL / g or less is more preferable.
本発明で用いられる活性炭の酸性官能基の量としては、０．０１ｍｅｑ／ｇ以上が好ましく、０．０３ｍｅｑ／ｇ以上がより好ましく、０．０５ｍｅｑ／ｇ以上がさらに好ましく、また３．００ｍｅｑ／ｇ以下が好ましく、２．５０ｍｅｑ／ｇ以下がより好ましく、２．００ｍｅｑ／ｇ以下がさらに好ましい。 The amount of the acidic functional group of the activated carbon used in the present invention is preferably 0.01 meq / g or more, more preferably 0.03 meq / g or more, further preferably 0.05 meq / g or more, and 3.00 meq / g. Or less, more preferably 2.50 meq / g or less, and even more preferably 2.00 meq / g or less.
本発明の活性炭の改質方法では、加熱処理は不活性ガスまたは還元性ガス雰囲気下で行い、加熱処理の温度は５００℃〜２０００℃の範囲にあり、加熱処理の時間は１０分未満である。 In the method for reforming activated carbon of the present invention, the heat treatment is performed in an inert gas or reducing gas atmosphere, the temperature of the heat treatment is in the range of 500 ° C. to 2000 ° C., and the time of the heat treatment is less than 10 minutes. .
加熱処理で用いる不活性ガスとしては、窒素ガス、アルゴンガス、ヘリウムガス等が挙げられ、還元性ガスとしては、水素ガス、水素ガスと前記不活性ガスとの混合物等が挙げられる。不活性ガスまたは還元性ガス雰囲気下で加熱処理を行うことにより、活性炭に存在する水酸基やカルボキシル基等の酸性官能基の分解や脱離が起こりやすくなる。 Examples of the inert gas used in the heat treatment include nitrogen gas, argon gas, and helium gas. Examples of the reducing gas include hydrogen gas, a mixture of hydrogen gas and the inert gas, and the like. By performing the heat treatment in an inert gas or reducing gas atmosphere, acidic functional groups such as hydroxyl groups and carboxyl groups existing in the activated carbon are likely to be decomposed and eliminated.
不活性ガスまたは還元性ガス雰囲気下で加熱処理する方法としては、不活性ガスまたは還元性ガスを加熱炉内に流しながら加熱処理する方法が好ましい。この場合、不活性ガスまたは還元性ガスの流量は、１分間に炉内容積の０．０１倍〜２０倍の容積の不活性ガスまたは還元性ガスが炉内に供給されるようにすることが好ましい。 As a method of performing heat treatment in an inert gas or reducing gas atmosphere, a method of performing heat treatment while flowing an inert gas or reducing gas in a heating furnace is preferable. In this case, the flow rate of the inert gas or reducing gas may be such that the inert gas or reducing gas having a volume of 0.01 to 20 times the furnace volume is supplied into the furnace per minute. preferable.
本発明の活性炭の改質方法において、加熱処理の温度は、加熱処理により得られる改質活性炭の所望する性状に応じて適宜決められる。一般に活性炭は、様々な種類の酸性官能基を有している。活性炭に存在する酸性官能基は加熱処理により分解したり脱離したりするが、分解や脱離が起こる温度は酸性官能基の種類に応じて変わる。従って、加熱処理の温度は、改質活性炭が有していてもよい酸性官能基の種類の設定条件に応じて、適宜決められる。また、後述するように、酸性官能基は加熱処理により速やかに除去されるため、改質活性炭が有していてもよい酸性官能基の量は、加熱処理の時間を増減することで調整することは難しい。従って、加熱処理の温度を適宜設定して除去する酸性官能基の種類を調整することにより、改質活性炭が有する酸性官能基の量を調整することができる。 In the method for reforming activated carbon of the present invention, the temperature of the heat treatment is appropriately determined according to the desired properties of the modified activated carbon obtained by the heat treatment. In general, activated carbon has various kinds of acidic functional groups. The acidic functional group present in the activated carbon is decomposed or desorbed by heat treatment, but the temperature at which the decomposition or desorption occurs varies depending on the type of the acidic functional group. Therefore, the temperature of the heat treatment is appropriately determined according to the setting condition of the type of acidic functional group that the modified activated carbon may have. As will be described later, since the acidic functional group is quickly removed by the heat treatment, the amount of the acidic functional group that the modified activated carbon may have is adjusted by increasing or decreasing the heat treatment time. Is difficult. Therefore, the amount of the acidic functional group that the modified activated carbon has can be adjusted by adjusting the kind of the acidic functional group to be removed by appropriately setting the temperature of the heat treatment.
本発明の方法により得られる改質活性炭は、電気二重層キャパシタ用電極材料や吸着材等に用いることができるが、改質活性炭が有してもよい酸性官能基の種類や量はその用途に応じて変わる。例えば、改質活性炭を電気二重層キャパシタ用電極材料に適用する場合は、酸性官能基の量はできるだけ少ない方が好ましい。この場合、できるだけ多くの種類の酸性官能基を除去するために、加熱処理の温度は比較的高温に設定される。また、例えば、改質活性炭を吸着材に適用する場合は、吸着材が有する官能基の種類やその量に応じて吸着材の性能が変わるため、所望する吸着材の性能に応じて、加熱処理の温度を設定すればよい。例えば、ある程度酸性官能基を有する吸着材を得る場合には、加熱処理の温度は比較的低温に設定し、改質活性炭を得ればよい。 The modified activated carbon obtained by the method of the present invention can be used for electrode materials for electric double layer capacitors, adsorbents, etc., but the type and amount of acidic functional group that the modified activated carbon may have depends on its use. It changes depending on the situation. For example, when the modified activated carbon is applied to an electrode material for an electric double layer capacitor, the amount of acidic functional groups is preferably as small as possible. In this case, in order to remove as many kinds of acidic functional groups as possible, the temperature of the heat treatment is set to a relatively high temperature. In addition, for example, when the modified activated carbon is applied to the adsorbent, the performance of the adsorbent changes depending on the type and amount of the functional group that the adsorbent has, so the heat treatment depends on the desired performance of the adsorbent. You can set the temperature of For example, when obtaining an adsorbent having an acidic functional group to some extent, the heat treatment temperature may be set to a relatively low temperature to obtain a modified activated carbon.
加熱処理の温度は、５００℃以上が好ましく、６００℃以上がより好ましく、８００℃以上がさらに好ましく、また２０００℃以下が好ましく、１６００℃以下がより好ましく、１２００℃以下がさらに好ましい。加熱処理の温度が５００℃以上であれば、酸性官能基の分解や脱離が起こりやすくなる。一方、加熱処理の温度を２０００℃まで上げれば大部分の酸性官能基を除去することが容易となるため、加熱処理の温度の上限は２０００℃とすればよい。 The temperature of the heat treatment is preferably 500 ° C. or higher, more preferably 600 ° C. or higher, further preferably 800 ° C. or higher, more preferably 2000 ° C. or lower, more preferably 1600 ° C. or lower, and further preferably 1200 ° C. or lower. When the temperature of the heat treatment is 500 ° C. or higher, the acidic functional group is likely to be decomposed or eliminated. On the other hand, if the temperature of the heat treatment is increased to 2000 ° C., it becomes easy to remove most of the acidic functional groups, and therefore the upper limit of the temperature of the heat treatment may be 2000 ° C.
加熱処理の温度とは、炉内の雰囲気温度を意味する。例えば、連続式炉の場合、炉の入口や出口に近いほど雰囲気温度が低く、炉内の加熱源設置領域では雰囲気温度が高くなる傾向がある。また、炉内の加熱源設置領域でも、炉の入口や出口側よりも炉の内部側の方が雰囲気温度が高くなる傾向がある。この場合、炉内の加熱源設置領域の最高雰囲気温度を、加熱処理の温度とする。 The temperature of heat treatment means the atmospheric temperature in the furnace. For example, in the case of a continuous furnace, the closer to the furnace inlet and outlet, the lower the ambient temperature and the higher the ambient temperature in the heating source installation area in the furnace. Further, even in the heating source installation region in the furnace, the atmosphere temperature tends to be higher on the inner side of the furnace than on the inlet or outlet side of the furnace. In this case, the highest atmospheric temperature in the heating source installation area in the furnace is set as the temperature of the heat treatment.
本発明の活性炭の改質方法では、加熱処理の時間を１０分未満とする。上述したように、酸性官能基の分解や脱離が起こる温度（酸性官能基除去温度）は酸性官能基の種類に応じて変わるが、ある酸性官能基の分解や脱離は、酸性官能基除去温度近辺で速やかに起こり、その反応時間（分解または脱離反応の時間）は１０分未満で十分である。従って、本発明では、加熱処理の温度を適宜設定し、１０分未満という短い時間加熱することにより、改質活性炭に残存する酸性官能基の種類を調整している。また、改質活性炭に残存する酸性官能基の種類を調整することにより、改質活性炭が有する全酸性官能基量を調整することもできる。 In the activated carbon reforming method of the present invention, the heat treatment time is set to less than 10 minutes. As described above, the temperature at which acidic functional groups decompose or desorb (acid functional group removal temperature) varies depending on the type of acidic functional group. It occurs quickly around the temperature, and the reaction time (decomposition or elimination reaction time) of less than 10 minutes is sufficient. Accordingly, in the present invention, the kind of acidic functional groups remaining in the modified activated carbon is adjusted by appropriately setting the temperature of the heat treatment and heating for a short time of less than 10 minutes. Moreover, the total amount of acidic functional groups of the modified activated carbon can be adjusted by adjusting the type of acidic functional groups remaining in the modified activated carbon.
一方、活性炭を加熱処理すると、活性炭の比表面積や細孔容積が低下するが、活性炭の比表面積や細孔容積は、加熱処理の時間が長くなるほどより低下する。加熱処理による活性炭の比表面積や細孔容積の低下は、加熱処理の温度よりも加熱処理の時間に大きく依存する。活性炭の比表面積や細孔容積の低下は、活性炭を電気二重層キャパシタ用電極材料用途に用いた場合の初期静電容量低下をもたらすとともに、活性炭を吸着材として用いる場合の吸着容量の低下も引き起こすため、好ましくない。従って、加熱処理の時間を１０分未満とする本発明の活性炭の改質方法は、改質活性炭の比表面積や細孔容積の低下を極力抑える点でも好ましい。 On the other hand, when the activated carbon is subjected to heat treatment, the specific surface area and pore volume of the activated carbon are decreased, but the specific surface area and pore volume of the activated carbon are further decreased as the heat treatment time is increased. The decrease in the specific surface area and pore volume of the activated carbon due to the heat treatment largely depends on the time of the heat treatment rather than the temperature of the heat treatment. The decrease in specific surface area and pore volume of activated carbon causes a decrease in initial capacitance when activated carbon is used for electrode materials for electric double layer capacitors, and also causes a decrease in adsorption capacity when activated carbon is used as an adsorbent. Therefore, it is not preferable. Therefore, the method for reforming activated carbon according to the present invention in which the heat treatment time is less than 10 minutes is also preferable from the viewpoint of minimizing the decrease in the specific surface area and pore volume of the modified activated carbon.
すなわち、本発明は、酸性官能基の分解や脱離が、活性炭の比表面積や細孔容積の低下と比較して速やかに起こることを見出したことに基づくものであり、本発明の活性炭の改質方法によれば、活性炭の比表面積や細孔容積の低下を極力抑えつつ、活性炭に存在する酸性官能基の量を効果的に低減することができる。 That is, the present invention is based on the finding that decomposition and elimination of acidic functional groups occur more rapidly than a decrease in the specific surface area and pore volume of activated carbon. According to the quality method, the amount of acidic functional groups present in the activated carbon can be effectively reduced while suppressing the decrease in the specific surface area and pore volume of the activated carbon as much as possible.
加熱処理の時間とは、連続式炉の場合は、炉内の加熱源設置領域を通過する時間を意味する。加熱源が複数設置されている場合には、最も入口側に設置された加熱源から最も出口側に設置された加熱源までを通過する時間を意味する。炉内であっても加熱源設置領域以外であったり、炉から排出された後に活性炭が熱を保有していたとしても、加熱処理の時間には計上しない。なお、加熱源としては、電熱ヒーターやバーナー等が示される。 In the case of a continuous furnace, the heat treatment time means the time for passing through the heating source installation area in the furnace. In the case where a plurality of heating sources are installed, this means the time required to pass from the heating source installed closest to the inlet side to the heating source installed closest to the outlet side. Even within the furnace, even if it is outside the heating source installation area or the activated carbon retains heat after being discharged from the furnace, it is not counted in the heat treatment time. In addition, as a heating source, an electric heater, a burner, etc. are shown.
バッチ式炉の場合、加熱処理の時間とは、炉内で加熱源（例えば、電熱ヒーターやバーナー）により恒温的に加熱される時間を意味する。バッチ式炉の場合、炉内を所定温度（恒温的に加熱する温度）まで昇温する時間は、加熱処理の時間に計上しない。また、所定温度で加熱した後は、炉内に熱が残存していたり、活性炭が熱を保有していたとしても、加熱処理の時間には計上しない。 In the case of a batch furnace, the heat treatment time means a time during which the furnace is heated constantly by a heating source (for example, an electric heater or burner) in the furnace. In the case of a batch furnace, the time for raising the temperature in the furnace to a predetermined temperature (temperature for constant temperature heating) is not counted as the time for the heat treatment. Further, after heating at a predetermined temperature, even if heat remains in the furnace or the activated carbon retains heat, it is not counted in the heat treatment time.
加熱処理の時間は、１０分未満が好ましく、５分以下がより好ましく、１分以下がさらに好ましい。一方、加熱処理の時間の下限は、特に限定されない。活性炭がわずかな時間でも規定の温度で加熱処理されれば、酸性官能基の分解や脱離が起こるからである。しかし、必要最低限の加熱処理の時間を確保し、確実に活性炭を加熱処理する観点から、加熱処理の時間は、０．１秒以上が好ましく、１秒以上がより好ましい。 The heat treatment time is preferably less than 10 minutes, more preferably 5 minutes or less, and even more preferably 1 minute or less. On the other hand, the lower limit of the heat treatment time is not particularly limited. This is because if the activated carbon is heat-treated at a specified temperature even for a short time, the acidic functional group is decomposed or eliminated. However, from the viewpoint of ensuring the necessary minimum heat treatment time and reliably heat-treating the activated carbon, the heat treatment time is preferably 0.1 seconds or more, and more preferably 1 second or more.
加熱処理の方式としては、連続式、バッチ式等の方式は問わない。加熱処理に用いる炉としては、例えば、ロータリーキルン、落下式急速焼成炉、トンネル炉、ローラーハース式焼成炉等の連続式炉；マッフル炉等のバッチ式炉を用いることができる。 As a heat treatment method, a continuous method, a batch method, or the like may be used. As a furnace used for the heat treatment, for example, a continuous furnace such as a rotary kiln, a drop rapid firing furnace, a tunnel furnace, or a roller hearth firing furnace; a batch furnace such as a muffle furnace can be used.
連続式炉において加熱処理の時間を短くする方法としては、例えば、次の方法が示される。ロータリーキルンを用いる場合は、レトルト全長を短くしたり、レトルトの回転数を上げたり、レトルトの傾斜角度を大きくすることで、加熱処理の時間を短くすることができる。落下式急速焼成炉を用いる場合は、１０秒程度までの加熱処理を容易に行うことができ、炉長（炉高）を短くすることでさらに加熱処理の時間を短縮することができる。トンネル炉、ローラーハース式焼成炉を用いる場合は、炉長を短くしたり、活性炭搬送速度を速くすることで、加熱処理の時間を短くすることができる。 As a method for shortening the heat treatment time in the continuous furnace, for example, the following method is shown. When the rotary kiln is used, the heat treatment time can be shortened by shortening the total length of the retort, increasing the rotation speed of the retort, or increasing the inclination angle of the retort. In the case of using a drop-type rapid firing furnace, the heat treatment up to about 10 seconds can be easily performed, and the heat treatment time can be further shortened by shortening the furnace length (furnace height). In the case of using a tunnel furnace or a roller hearth type firing furnace, the heat treatment time can be shortened by shortening the furnace length or increasing the activated carbon conveyance speed.
加熱処理の時間の計測方法について、ロータリーキルンを例に、図１により説明する。ロータリーキルン１は、活性炭を内部で加熱処理する内筒（レトルト）２と、内筒２を覆う外筒３とを有している。内筒２の外側と外筒３の内側との間にはヒーター４が設置されている。内筒２は、原料活性炭投入側の入口開口５と、加熱処理された改質活性炭が排出される出口開口６とを有している。入口開口５には、原料活性炭を供給するためのフィーダー７が備わっている。フィーダー７は、内筒２の入口開口５に挿入された供給端８を有し、フィーダー７の供給端８の他方端近辺には、原料活性炭供給ホッパ９が接続している。ここで、ヒーター４の内筒２の軸方向の長さをｘとし、フィーダー７の供給端８から内筒２の出口開口６までの長さをｙとする。
A method for measuring the heat treatment time will be described with reference to FIG. 1, taking a rotary kiln as an example. The rotary kiln 1 has an inner cylinder (retort) 2 that heat-treats activated carbon inside, and an outer cylinder 3 that covers the
原料活性炭は、ホッパ９からフィーダー７を介して供給端８から内筒２に供給され、このときの時間をＴ1とする。内筒２に供給された原料活性炭は、ロータリーキルンの回転により出口開口６側へ送り出され、出口開口６から改質活性炭として排出される、改質活性炭が排出され始めた時間をＴ2とする。このとき、加熱処理の時間は下記式により算出される。
加熱処理の時間＝（Ｔ2−Ｔ1）×ｘ／ｙ
Base activated carbon is supplied to the
Heat treatment time = (T 2 −T 1 ) × x / y
加熱処理することにより得られる改質活性炭の比表面積や細孔容積は、加熱処理前の活性炭と比較してできるだけ低下しないことが好ましい。例えば、改質活性炭の比表面積としては、５００ｍ2／ｇ以上が好ましく、１，０００ｍ2／ｇ以上がより好ましく、２，０００ｍ2／ｇ以上がさらに好ましく、また４，０００ｍ2／ｇ以下が好ましく、３，８００ｍ2／ｇ以下がより好ましく、３，５００ｍ2／ｇ以下がさらに好ましい。 It is preferable that the specific surface area and pore volume of the modified activated carbon obtained by the heat treatment are not reduced as much as possible as compared with the activated carbon before the heat treatment. For example, as the specific surface area of the modified activated carbon, 500 meters is preferably not less than 2 / g, more preferably at least 1,000 m 2 / g, more preferably not less than 2,000 m 2 / g, also 4,000 m 2 / g or less Preferably, 3,800 m 2 / g or less is more preferable, and 3,500 m 2 / g or less is more preferable.
改質活性炭の細孔容積としては、０．１ｍＬ／ｇ以上が好ましく、０．４ｍＬ／ｇ以上がより好ましく、１．０ｍＬ／ｇ以上がさらに好ましく、また３．０ｍＬ／ｇ以下が好ましく、２．５ｍＬ／ｇ以下がより好ましく、２．０ｍＬ／ｇ以下がさらに好ましい。改質活性炭の比表面積が５００ｍ2／ｇ以上、または細孔容積が０．１ｍＬ／ｇ以上であれば、改質活性炭を電気二重層キャパシタに適用した場合、質量基準静電容量の大きいキャパシタを得やすくなる。 The pore volume of the modified activated carbon is preferably 0.1 mL / g or more, more preferably 0.4 mL / g or more, further preferably 1.0 mL / g or more, and preferably 3.0 mL / g or less. 0.5 mL / g or less is more preferable, and 2.0 mL / g or less is more preferable. If the specific surface area of the modified activated carbon is 500 m 2 / g or more, or the pore volume is 0.1 mL / g or more, when the modified activated carbon is applied to an electric double layer capacitor, a capacitor with a large mass-based capacitance is required. It becomes easy to obtain.
加熱処理することにより得られる改質活性炭の酸性官能基の量は、所望の用途に応じて適宜設定される。加熱処理により得られる改質活性炭を電気二重層キャパシタ用電極材料に適用する場合は、酸性官能基の量はできるだけ少ない方が好ましく、例えば、１．０ｍｅｑ／ｇ以下が好ましく、０．５ｍｅｑ／ｇ以下がより好ましく、０．２ｍｅｑ／ｇ以下がさらに好ましい。酸性官能基の量が１．０ｍｅｑ／ｇ以下であれば、改質活性炭を電気二重層キャパシタに適用した場合、長期使用による静電容量の低下を低く抑えやすくなる。なお、改質活性炭の酸性官能基の量の下限は特に規定されない。 The amount of the acidic functional group of the modified activated carbon obtained by the heat treatment is appropriately set according to the desired application. When the modified activated carbon obtained by heat treatment is applied to an electrode material for an electric double layer capacitor, the amount of acidic functional groups is preferably as small as possible, for example, 1.0 meq / g or less is preferable, and 0.5 meq / g The following is more preferable, and 0.2 meq / g or less is more preferable. If the amount of the acidic functional group is 1.0 meq / g or less, when the modified activated carbon is applied to an electric double layer capacitor, it is easy to suppress a decrease in capacitance due to long-term use. In addition, the minimum in particular of the quantity of the acidic functional group of modified activated carbon is not prescribed | regulated.
本発明の活性炭の改質方法により得られる改質活性炭は、電気二重層キャパシタ用電極材料に好適に使用できる。従って、前記改質活性炭を使用して、電気二重層キャパシタ用電極や電気二重層キャパシタを製造することが可能である。これら電極やキャパシタを製造するには、公知の製法を使用するとよい。 The modified activated carbon obtained by the method for modifying activated carbon of the present invention can be suitably used as an electrode material for electric double layer capacitors. Therefore, it is possible to produce an electric double layer capacitor electrode or an electric double layer capacitor using the modified activated carbon. In order to manufacture these electrodes and capacitors, a known manufacturing method may be used.
本発明の活性炭の改質方法により得られる改質活性炭を用いて作製される電気二重層キャパシタは、加熱処理による活性炭の比表面積や細孔容積の低下が極力抑えられているため、初期静電容量を高くすることができる。また、活性炭に存在する酸性官能基の量が効果的に低減されているため、長期使用による静電容量の低下も低く抑えられる。 The electric double layer capacitor produced by using the modified activated carbon obtained by the method for reforming activated carbon of the present invention can suppress the decrease in the specific surface area and pore volume of the activated carbon due to heat treatment as much as possible. The capacity can be increased. Moreover, since the amount of acidic functional groups present in the activated carbon is effectively reduced, the decrease in capacitance due to long-term use can be suppressed to a low level.
電気二重層キャパシタ用電極としては、例えば、電極材料である活性炭、導電性付与剤、およびバインダーを混練し、溶媒を添加してペーストを調製し、このペーストをアルミ箔等の集電板に塗布した後、溶媒を乾燥除去したものや、前記ペーストを金型に入れプレス成形したものが挙げられる。 As an electrode for an electric double layer capacitor, for example, activated carbon that is an electrode material, a conductivity imparting agent, and a binder are kneaded, a solvent is added to prepare a paste, and this paste is applied to a current collector plate such as an aluminum foil Thereafter, the solvent is removed by drying, and the paste is put in a mold and press-molded.
この電極に使用されるバインダーとしては、ポリテトラフルオロエチレン、ポリフッ化ビニリデン等のフッ素系高分子化合物や、カルボキシメチルセルロース、スチレン−ブタジエンゴム、石油ピッチ、フェノール樹脂等を使用することができる。また、導電性付与剤としては、アセチレンブラック、ケッチェンブラック等を使用することができる。 As the binder used for this electrode, fluorine polymer compounds such as polytetrafluoroethylene and polyvinylidene fluoride, carboxymethylcellulose, styrene-butadiene rubber, petroleum pitch, phenol resin, and the like can be used. As the conductivity-imparting agent, acetylene black, ketjen black, or the like can be used.
電気二重層キャパシタは、一般に、電極、電解液、およびセパレータを主要構成とし、一対の電極間にセパレータを配置した構造となっている。電解液を例示すれば、プロピレンカーボネート、エチレンカーボネート、メチルエチルカーボネート等の有機溶剤にアミジン塩を溶解した電解液、過塩素酸の４級アンモニウム塩を溶解した電解液、４級アンモニウムやリチウム等のアルカリ金属の四フッ化ホウ素塩や六フッ化リン塩を溶解した電解液、４級ホスホニウム塩を溶解した電解液等が挙げられる。また、セパレータを例示すれば、セルロース、ガラス繊維、または、ポリエチレンやポリプロピレン等のポリオレフィンを主成分とした不織布、クロス、微孔フィルムが挙げられる。 An electric double layer capacitor generally has a structure in which an electrode, an electrolytic solution, and a separator are main components, and a separator is disposed between a pair of electrodes. Examples of the electrolytic solution include an electrolytic solution in which an amidine salt is dissolved in an organic solvent such as propylene carbonate, ethylene carbonate, and methyl ethyl carbonate, an electrolytic solution in which a quaternary ammonium salt of perchloric acid is dissolved, quaternary ammonium, lithium, and the like. Examples include an electrolytic solution in which an alkali metal boron tetrafluoride salt or phosphorous hexafluoride is dissolved, and an electrolytic solution in which a quaternary phosphonium salt is dissolved. Moreover, if a separator is illustrated, the nonwoven fabric, cloth, and microporous film which have cellulose, glass fiber, or polyolefins, such as polyethylene and a polypropylene, as a main component are mentioned.
以下に、実施例を示すことにより本発明を更に詳細に説明するが、本発明の範囲はこれらに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited thereto.
＜活性炭の改質＞
［製造例１］
テキサコ社製ディレードコークスをアルカリ賦活処理し、水および酸性液により洗浄した後、１１５℃で乾燥させた活性炭（原料活性炭）を、窒素ガス雰囲気下、加熱処理した。加熱処理には、レトルトの外側に電熱ヒーターが設置された連続式ロータリーキルン（株式会社東洋製作所製）を用いた。ロータリーキルンは、レトルト全長が１０００ｍｍであり、ヒーターが設置された領域（加熱源設置領域）の長さが１００ｍｍであった。加熱処理は、レトルト内に窒素ガスを活性炭と並流で流しながら、レトルト外部より加熱することにより、加熱処理の温度１０００℃にて行った。加熱処理では、レトルトを活性炭投入側が上になるように５°傾け、レトルトの回転数を８ｒｐｍに調整した。原料活性炭が加熱源設置領域を通過する時間（加熱処理の時間）は２秒であった。なお、レトルトから排出された活性炭は自然放冷により冷却した。
<Modification of activated carbon>
[Production Example 1]
Activated activated carbon (raw material activated carbon) dried at 115 ° C. was heat-treated in a nitrogen gas atmosphere after alkali activation of Texaco-made delayed coke and washing with water and an acidic liquid. For the heat treatment, a continuous rotary kiln (manufactured by Toyo Manufacturing Co., Ltd.) in which an electric heater was installed outside the retort was used. The rotary kiln had a retort total length of 1000 mm, and the length of the area where the heater was installed (heating source installation area) was 100 mm. The heat treatment was performed at a heat treatment temperature of 1000 ° C. by heating from the outside of the retort while flowing nitrogen gas in the retort in parallel with the activated carbon. In the heat treatment, the retort was tilted by 5 ° so that the activated carbon charging side was up, and the rotation speed of the retort was adjusted to 8 rpm. The time (heat treatment time) for the raw material activated carbon to pass through the heating source installation region was 2 seconds. The activated carbon discharged from the retort was cooled by natural cooling.
［製造例２］
製造例１で用いた原料活性炭を、窒素ガス雰囲気下、加熱処理した。加熱処理には、レトルトの外側に電熱ヒーターが設置された外熱式ジャバラキルン（岩佐機械工業株式会社製）を用いた。ジャバラキルンは、レトルト全長２９６５ｍｍであり、ヒーターが設置された領域（加熱源設置領域）の長さが１３００ｍｍであった。加熱処理は、レトルト内に窒素ガスを活性炭と並流で流しながら、レトルト外部より加熱することにより、加熱処理の温度１０００℃にて行った。なお、加熱源設置領域では、２００ｍｍ間隔で７地点の雰囲気温度を測定し、その中で最も高い温度を示したレトルト入口側および出口側から４点目の地点（つまり、７地点の測定地点のうちの真ん中の地点）の温度が１０００℃であった。原料活性炭が加熱源設置領域を通過する時間（加熱処理の時間）は５分であった。なお、レトルトから排出された活性炭は自然放冷により冷却した。
[Production Example 2]
The raw material activated carbon used in Production Example 1 was heat-treated in a nitrogen gas atmosphere. For the heat treatment, an externally heated bellows kiln (manufactured by Iwasa Machinery Co., Ltd.) in which an electric heater was installed outside the retort was used. The bellows kiln had a retort total length of 2965 mm, and the length of the area where the heater was installed (heating source installation area) was 1300 mm. The heat treatment was performed at a heat treatment temperature of 1000 ° C. by heating from the outside of the retort while flowing nitrogen gas in the retort in parallel with the activated carbon. In the heating source installation area, the ambient temperature at 7 points is measured at intervals of 200 mm, and the fourth point from the retort inlet side and outlet side showing the highest temperature (that is, the seven measurement points). The temperature at the middle point) was 1000 ° C. The time (heat treatment time) for the raw material activated carbon to pass through the heating source installation region was 5 minutes. The activated carbon discharged from the retort was cooled by natural cooling.
［製造例３］
製造例２において、キルン回転速度を下げることにより加熱処理の時間を９分とした以外は、製造例２と同様に原料活性炭を加熱処理した。
[Production Example 3]
In Production Example 2, the raw material activated carbon was heat-treated in the same manner as in Production Example 2 except that the heat treatment time was set to 9 minutes by lowering the kiln rotation speed.
［製造例４］
製造例１で用いた原料活性炭を、窒素ガス雰囲気下、加熱処理した。加熱処理には、箱形マッフル炉を用いた。炉内に原料活性炭を入れた後、窒素ガスを流しながら、２時間かけて炉内の温度を１０００℃まで昇温し、炉内の温度を１０００℃で２時間保持し、その後加熱を止め、炉内温度が１００℃以下になったところで活性炭を取り出した。製造例４では、加熱処理の時間は２時間であった。
[Production Example 4]
The raw material activated carbon used in Production Example 1 was heat-treated in a nitrogen gas atmosphere. A box-shaped muffle furnace was used for the heat treatment. After putting the raw material activated carbon in the furnace, the temperature in the furnace was raised to 1000 ° C. over 2 hours while flowing nitrogen gas, the temperature in the furnace was kept at 1000 ° C. for 2 hours, and then the heating was stopped, The activated carbon was taken out when the temperature in the furnace became 100 ° C. or lower. In Production Example 4, the heat treatment time was 2 hours.
［製造例５」
製造例１とは異なるロットのテキサコ社製ディレードコークスをアルカリ賦活処理し、水および酸性液により洗浄した後、１１５℃で乾燥させた活性炭（原料活性炭）を、窒素ガス雰囲気下、加熱処理した。加熱処理条件は、加熱処理の温度を８００℃とした以外は、製造例１と同様に行った。
[Production Example 5]
The activated carbon (raw material activated carbon) dried at 115 ° C. was heat-treated in a nitrogen gas atmosphere after alkali activation treatment of a delayed coke made by Texaco, which was different from Production Example 1, was washed with water and an acidic liquid. The heat treatment conditions were the same as in Production Example 1 except that the temperature of the heat treatment was 800 ° C.
［製造例６］
製造例５で用いた原料活性炭を、加熱処理の温度８００℃とした以外は製造例２と同様の処理条件で、加熱処理を行った。
[Production Example 6]
The raw material activated carbon used in Production Example 5 was subjected to heat treatment under the same treatment conditions as Production Example 2 except that the temperature of the heat treatment was 800 ° C.
［製造例７］
製造例６において、加熱処理の時間を９分とした以外は、製造例６と同様に原料活性炭を加熱処理した。
[Production Example 7]
In Production Example 6, the raw material activated carbon was heat-treated in the same manner as in Production Example 6 except that the heat treatment time was 9 minutes.
［製造例８］
製造例５で用いた原料活性炭を、加熱処理の温度８００℃とした以外は製造例４と同様の処理条件で、加熱処理を行った。
[Production Example 8]
The heat treatment was performed under the same treatment conditions as in Production Example 4 except that the raw material activated carbon used in Production Example 5 was heated to 800 ° C.
＜電気二重層キャパシタの作製＞
［電極の作製］
製造例１〜８で得られた各々の活性炭に、ポリテトラフルオロエチレン粉末（市販のＰＴＦＥ）とアセチレンブラックとを、電極材料：ＰＴＦＥ：アセチレンブラック＝８：１：１（質量比）になるように混合し、ペースト状態になるまで混練した。次いで、ミニブレンダーで粉砕し、目開き５００μｍのステンレス鋼製篩により篩い分けし、篩の通過分を集めた。次いで、前記篩の通過分を、直径１インチの金型に入れ、５００ｋｇ／ｃｍ2の圧力でプレス成形して、直径１インチ、厚み０．５ｍｍのコイン型の電極を作製した。
<Production of electric double layer capacitor>
[Production of electrodes]
Polytetrafluoroethylene powder (commercially available PTFE) and acetylene black are added to each activated carbon obtained in Production Examples 1 to 8 so that the electrode material: PTFE: acetylene black = 8: 1: 1 (mass ratio). And kneaded until a paste is obtained. Subsequently, it grind | pulverized with the mini blender and sieved with the stainless steel sieve of 500 micrometers of openings, and the passage part of the sieve was collected. Next, the passing portion of the sieve was put into a 1 inch diameter mold and press molded at a pressure of 500 kg / cm 2 to produce a coin type electrode having a diameter of 1 inch and a thickness of 0.5 mm.
［電気二重層キャパシタの組み立て］
真空条件下、２００℃、１時間の条件で電極を乾燥した後、窒素ガスを流通させたグローブボックス内で電解液（テトラエチルアンモニウムテトラフルオロボレートが１ｍｏｌ／ｌのプロピレンカーボネート溶液）を電極に真空含浸させた。この電極を、電解液を含浸させたポリプロピレン製セパレータ（Ｃｅｌｇａｒｄ社製「セルガード♯３５０１」）で挟み、さらにアルミニウム板で挟んで電気二重層キャパシタを組み立てた。
[Assembly of electric double layer capacitor]
After drying the electrode under vacuum conditions at 200 ° C. for 1 hour, the electrode is vacuum impregnated with an electrolyte (a propylene carbonate solution containing 1 mol / l of tetraethylammonium tetrafluoroborate) in a glove box in which nitrogen gas is circulated. I let you. The electrode was sandwiched between polypropylene separators impregnated with electrolyte (“Celguard # 3501” manufactured by Celgard), and further sandwiched between aluminum plates to assemble an electric double layer capacitor.
＜活性炭の分析方法＞
［比表面積］
マイクロメリティックス社製ＡＳＡＰ−２４００窒素吸着装置を使用し、活性炭の窒素吸着等温線を測定するＢＥＴ法により比表面積を求めた。
<Analytical method of activated carbon>
[Specific surface area]
The specific surface area was calculated | required by BET method which measures the nitrogen adsorption isotherm of activated carbon using the ASAP-2400 nitrogen adsorption apparatus by Micromeritics.
［細孔容積］
マイクロメリティックス社製ＡＳＡＰ−２４００窒素吸着装置を使用し、相対圧Ｐ／Ｐ0（Ｐ：吸着平衡にある吸着質の気体の圧力、Ｐ0：吸着温度における吸着質の飽和蒸気圧）が０．９３までの窒素吸着量を測定するＢＥＴ法により求めた。
[Pore volume]
Using an ASAP-2400 nitrogen adsorption device manufactured by Micromeritics, the relative pressure P / P 0 (P: the pressure of the adsorbate gas in the adsorption equilibrium, P 0 : the saturated vapor pressure of the adsorbate at the adsorption temperature) is The nitrogen adsorption amount up to 0.93 was determined by the BET method.
［平均細孔径］
細孔の形状をシリンダー状と仮定し、下記式に基づき平均細孔径を算出した。
平均細孔径（Å）＝細孔容積（ｍ3／ｇ）／比表面積（ｍ2／ｇ）×４×１０10
[Average pore diameter]
Assuming the shape of the pores to be cylindrical, the average pore diameter was calculated based on the following formula.
Average pore diameter (Å) = pore volume (m 3 / g) / specific surface area (m 2 / g) × 4 × 10 10
［酸性官能基の量］
酸性官能基の量は、Ｂｏｅｈｍ法に従い、活性炭をナトリウムエトキシドと反応させた後、未反応のナトリウムエトキシドを塩酸で滴定して定量することにより求めた。具体的には、共栓付き三角フラスコ（容量１００ｍｌ）に、活性炭２ｇ、および０．１ｍｏｌ／ｌのナトリウムエトキシド５０ｍｌを加え、３０分間の振とう後、３０分間放置した。この振とうと放置を３回繰り返した。次いで、更に２４時間放置し、ろ過分離して得られたろ液２５ｍｌを、１／１０規定の塩酸で中和滴定した。また、ブランクテストも行った。そして、次式により酸性官能基の量を算出した。なお、Ｂｏｅｈｍ法については、H.P.Boehm, Adzan. Catal, 16, 179 (1966)に、その詳細が記載されている。
酸性官能基の量（ｍｅｑ／ｇ）＝（ａ−ｂ）×０．１／（Ｓ×２５／５０）
０．１：滴定に使用した塩酸濃度（ｍｏｌ／ｌ）
ａ：ブランクテストにおける滴定量（ｍｌ）
ｂ：活性炭を使用したときの滴定量（ｍｌ）
Ｓ：活性炭質量（ｇ）
２５：ろ液分取量（ｍｌ）
５０：ナトリウムエトキシド量（ｍｌ）
[Amount of acidic functional group]
The amount of the acidic functional group was determined by reacting activated carbon with sodium ethoxide and titrating unreacted sodium ethoxide with hydrochloric acid according to the Boehm method. Specifically, 2 g of activated carbon and 50 ml of 0.1 mol / l sodium ethoxide were added to a conical stoppered Erlenmeyer flask (capacity: 100 ml), and left for 30 minutes after shaking for 30 minutes. This shaking and leaving was repeated three times. Then, the mixture was further left for 24 hours, and 25 ml of the filtrate obtained by filtration and separation was neutralized and titrated with 1/10 N hydrochloric acid. A blank test was also conducted. And the quantity of the acidic functional group was computed by following Formula. The Boehm method is described in detail in HP Boehm, Adzan. Catal, 16, 179 (1966).
Amount of acidic functional group (meq / g) = (ab) × 0.1 / (S × 25/50)
0.1: Concentration of hydrochloric acid used for titration (mol / l)
a: Titration amount in blank test (ml)
b: Titration volume when using activated carbon (ml)
S: Mass of activated carbon (g)
25: Filtrate fraction (ml)
50: Sodium ethoxide amount (ml)
＜キャパシタの性能評価試験方法＞
［静電容量］
充放電装置（楠本化成株式会社製ETAC Ver4.4）の充放電端子をキャパシタのアルミニウム板に接続し、２５℃で、集電板間電圧が２．５Ｖになるまで４０ｍＡの定電流充電を行い、続けて、２．５Ｖの定電圧で３０分間充電した。充電後、定電流（放電電流＝０．０１０Ａ）でキャパシタの放電を行った。このとき、キャパシタ電圧（Ｖ１，Ｖ２）と放電時間（ｔ１，ｔ２）を測定し、下式からキャパシタの静電容量を算出した、そして、キャパシタの静電容量を電極における電極材料層の総質量で除することで質量基準静電容量を算出し、キャパシタの静電容量を電極における電極材料層の総体積で除することで体積基準静電容量を算出した。
Ｆ（Ｖ１−Ｖ２）＝−Ｉ（ｔ１−ｔ２）
Ｆ：キャパシタの静電容量（Ｆ）
Ｖ１：２．０（Ｖ）
Ｖ２：１．５（Ｖ）
ｔ１：キャパシタ電圧がＶ１になったときの放電時間（秒）
ｔ２：キャパシタ電圧がＶ２になったときの放電時間（秒）
Ｉ：０．０１０（Ａ）
<Capacitor performance evaluation test method>
[Capacitance]
Connect the charging / discharging terminal of the charging / discharging device (ETAC Ver4.4 manufactured by Enomoto Kasei Co., Ltd.) to the aluminum plate of the capacitor and perform constant current charging of 40 mA at 25 ° C until the voltage between the current collector plates reaches 2.5V. Subsequently, the battery was charged with a constant voltage of 2.5 V for 30 minutes. After charging, the capacitor was discharged with a constant current (discharge current = 0.010 A). At this time, the capacitor voltage (V1, V2) and the discharge time (t1, t2) were measured, the capacitance of the capacitor was calculated from the following equation, and the capacitance of the capacitor was calculated as the total mass of the electrode material layer in the electrode. The volume-based capacitance was calculated by dividing the capacitance of the capacitor by the total volume of the electrode material layer in the electrode.
F (V1-V2) =-I (t1-t2)
F: Capacitance of capacitor (F)
V1: 2.0 (V)
V2: 1.5 (V)
t1: Discharge time when the capacitor voltage reaches V1 (seconds)
t2: Discharge time when the capacitor voltage reaches V2 (seconds)
I: 0.010 (A)
［内部抵抗］
前記静電容量の評価と同じ条件でキャパシタ充電を行った後、定電流（放電電流＝０．０１０Ａ）でキャパシタの放電を行った。このとき、キャパシタ電圧（Ｖ１，Ｖ２）と放電時間（ｔ１，ｔ２）を測定し、下記の２式からキャパシタの抵抗を算出した。
Ｖ１＝（Ｖ１−Ｖ２）／（ｔ１−ｔ２）
Ｒ＝（Ｖ０−ＶＸ）／Ｉ
Ｒ：抵抗（Ω）
Ｖ０：２．５（Ｖ）
ＶＸ：みなし電圧（Ｖ）
Ｖ１：２．０（Ｖ）
Ｖ２：１．５（Ｖ）
ｔ１：キャパシタ電圧がＶ１になったときの放電時間（秒）
ｔ２：キャパシタ電圧がＶ２になったときの放電時間（秒）
Ｉ：０．０１０（Ａ）
[Internal resistance]
After charging the capacitor under the same conditions as the evaluation of the capacitance, the capacitor was discharged with a constant current (discharge current = 0.010 A). At this time, the capacitor voltage (V1, V2) and the discharge time (t1, t2) were measured, and the resistance of the capacitor was calculated from the following two equations.
V1 = (V1-V2) / (t1-t2)
R = (V0−VX) / I
R: Resistance (Ω)
V0: 2.5 (V)
VX: Deemed voltage (V)
V1: 2.0 (V)
V2: 1.5 (V)
t1: Discharge time when the capacitor voltage reaches V1 (seconds)
t2: Discharge time when the capacitor voltage reaches V2 (seconds)
I: 0.010 (A)
［１０００時間後の静電容量および内部抵抗］
キャパシタを、７０℃の恒温槽内で２．７Ｖの電圧を印加した状態で１０００時間保持した。その後、恒温槽から取り出し、上記した方法により、静電容量と内部抵抗を算出した。
[Capacitance and internal resistance after 1000 hours]
The capacitor was held in a constant temperature bath at 70 ° C. with a voltage of 2.7 V applied for 1000 hours. Then, it took out from the thermostat, and the electrostatic capacity and the internal resistance were calculated by the method described above.
＜分析および試験結果＞
原料活性炭および製造例１〜８で得られた改質活性炭の分析結果と、原料活性炭および前記改質活性炭を用いて作製した電気二重層キャパシタの性能評価試験結果を、表１，２に示す。
<Analysis and test results>
Tables 1 and 2 show the analysis results of the raw material activated carbon and the modified activated carbon obtained in Production Examples 1 to 8, and the performance evaluation test results of the electric double layer capacitor produced using the raw material activated carbon and the modified activated carbon.
原料活性炭と改質活性炭の分析結果を見ると、比表面積と細孔容積は加熱処理の時間に対し緩やかに減少するのに対し、酸性官能基の量は２秒間の加熱処理だけで大きく減少し、それ以上の時間加熱処理しても酸性官能基の量はほとんど変化しなかった。このことから、酸性官能基の分解や脱離は、活性炭の比表面積や細孔容積の低下と比較して、速やかに起こることが分かる。 Looking at the analysis results of raw activated carbon and modified activated carbon, the specific surface area and pore volume decrease gradually with respect to the heat treatment time, whereas the amount of acidic functional groups greatly decreases only with the heat treatment for 2 seconds. The amount of the acidic functional group hardly changed even when the heat treatment was performed for a longer time. From this, it can be seen that the decomposition and elimination of the acidic functional group occur more rapidly than the decrease in the specific surface area and pore volume of the activated carbon.
原料活性炭および改質活性炭を用いて作製した電気二重層キャパシタの性能評価試験結果を見ると、静電容量（初期）は加熱処理の時間に対し緩やかに減少する傾向を示した。静電容量の値は、比表面積および細孔容積にほぼ比例した。つまり、加熱処理の時間を短くすることで、比表面積や細孔容積の低下を極力抑え、電気二重層キャパシタの静電容量を高くすることができた。一方、内部抵抗（初期）は、加熱処理により減少したが、加熱処理の時間との相関はほとんど見られなかった。 Looking at the performance evaluation test results of the electric double layer capacitor produced using the raw activated carbon and the modified activated carbon, the electrostatic capacity (initial) showed a tendency to gradually decrease with respect to the heat treatment time. The capacitance value was approximately proportional to the specific surface area and pore volume. That is, by shortening the heat treatment time, it was possible to suppress the decrease in the specific surface area and the pore volume as much as possible, and to increase the capacitance of the electric double layer capacitor. On the other hand, the internal resistance (initial) was decreased by the heat treatment, but there was almost no correlation with the heat treatment time.
１０００時間後の静電容量を初期静電容量で除した静電容量維持率については、加熱処理を行った製造例１〜８は、いずれも原料活性炭より高い静電容量維持率を示した。静電容量維持率は、加熱処理の時間との相関はほとんど見られなかった。すなわち、加熱処理により活性炭の酸性官能基量が低減した結果、長期使用による静電容量の低下も低く抑えることができたと考えられる。 About the electrostatic capacity maintenance rate which remove | divided the electrostatic capacity 1000 hours after by the initial stage electrostatic capacitance, all the manufacture examples 1-8 which performed heat processing showed the electrostatic capacity maintenance rate higher than raw material activated carbon. There was almost no correlation between the capacitance maintenance ratio and the heat treatment time. That is, as a result of the reduction in the amount of acidic functional groups of the activated carbon by heat treatment, it is considered that the decrease in capacitance due to long-term use could be suppressed to a low level.
本発明の活性炭の改質方法により得られる活性炭は、電気二重層キャパシタ用電極材料、電気二重層キャパシタ用電極、電気二重層キャパシタ、吸着材等の用途へ適用できる。 The activated carbon obtained by the method for reforming activated carbon of the present invention can be applied to uses such as electrode materials for electric double layer capacitors, electrodes for electric double layer capacitors, electric double layer capacitors, adsorbents and the like.
１： ロータリーキルン
２： 内筒
３： 外筒
４： ヒーター
７： フィーダー
９： ホッパ
1: Rotary kiln 2: Inner cylinder 3: Outer cylinder 4: Heater 7: Feeder 9: Hopper
Claims (5)
前記加熱処理の温度が５００℃〜２０００℃の範囲にあり、
前記加熱処理の時間が１０分未満であることを特徴とする活性炭の改質方法。 A method for reforming activated carbon in which activated carbon is heat-treated in an inert gas or reducing gas atmosphere,
The temperature of the heat treatment is in the range of 500 ° C to 2000 ° C,
A method for reforming activated carbon, wherein the heat treatment time is less than 10 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008281686A JP5676074B2 (en) | 2008-10-31 | 2008-10-31 | Method for reforming activated carbon |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008281686A JP5676074B2 (en) | 2008-10-31 | 2008-10-31 | Method for reforming activated carbon |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2010105885A true JP2010105885A (en) | 2010-05-13 |
| JP5676074B2 JP5676074B2 (en) | 2015-02-25 |
Family
ID=42295709
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2008281686A Active JP5676074B2 (en) | 2008-10-31 | 2008-10-31 | Method for reforming activated carbon |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5676074B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012028668A (en) * | 2010-07-27 | 2012-02-09 | Air Water Inc | Coated electrode and capacitor using it |
| KR101137719B1 (en) * | 2010-12-07 | 2012-04-24 | 한국세라믹기술원 | Manufacturing method of active carbon electrode for supercapacitor |
| JP2015154039A (en) * | 2014-02-19 | 2015-08-24 | 住友電気工業株式会社 | Capacitor and charge and discharge method thereof |
| KR20160027810A (en) * | 2014-09-02 | 2016-03-10 | 한국전기연구원 | Carbon material vertical surface treatment apparatus |
| CN105399095A (en) * | 2015-12-28 | 2016-03-16 | 大连理工大学 | Apparatus and method for preparing high specific surface area active carbon through alkali activation process |
| WO2016122070A1 (en) * | 2015-01-29 | 2016-08-04 | 한국전기연구원 | Method for modifying carbon material electrode surface by current carrying, surface-modified carbon material electrode, and electrochemical capacitor comprising surface-modified carbon material electrode |
| JP2017076767A (en) * | 2015-10-15 | 2017-04-20 | ジーエス エナジー コーポレーション | Active carbon for electric double-layer capacitor electrode and manufacturing method of the same |
| JP2017088443A (en) * | 2015-11-09 | 2017-05-25 | 住友電気工業株式会社 | Porous carbon material, manufacturing method, and electrode and capacitor using the same |
| WO2022174335A1 (en) * | 2021-02-17 | 2022-08-25 | Supercap Technologies Corp. | Sweeping gas process for production of activated carbon-based electrode materials |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000169127A (en) * | 1998-11-30 | 2000-06-20 | Kyocera Corp | Solid activated carbon structure, electric double layer capacitor using the same and their production |
| JP2003209029A (en) * | 2002-01-11 | 2003-07-25 | Meidensha Corp | Double-layered electric capacitor having improved withstand voltage |
| JP2005129722A (en) * | 2003-10-23 | 2005-05-19 | Nippon Oil Corp | Electric double layer capacitor, activated carbon for its electrode, and method of producing the carbon |
| JP2005129707A (en) * | 2003-10-23 | 2005-05-19 | Nippon Oil Corp | Electric double layer capacitor, activated carbon for its electrode, and method of producing the carbon |
| JP2007505490A (en) * | 2003-09-11 | 2007-03-08 | 本田技研工業株式会社 | Method for producing activated carbon for electrode of electric double layer capacitor |
| JP2008120610A (en) * | 2006-11-09 | 2008-05-29 | Sumitomo Chemical Co Ltd | Activated carbon and method for producing the same |
| JP2008181949A (en) * | 2007-01-23 | 2008-08-07 | Hitachi Chem Co Ltd | Electrode material for electric double-layer capacitor and the electric double-layer capacitor |
-
2008
- 2008-10-31 JP JP2008281686A patent/JP5676074B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000169127A (en) * | 1998-11-30 | 2000-06-20 | Kyocera Corp | Solid activated carbon structure, electric double layer capacitor using the same and their production |
| JP2003209029A (en) * | 2002-01-11 | 2003-07-25 | Meidensha Corp | Double-layered electric capacitor having improved withstand voltage |
| JP2007505490A (en) * | 2003-09-11 | 2007-03-08 | 本田技研工業株式会社 | Method for producing activated carbon for electrode of electric double layer capacitor |
| JP2005129722A (en) * | 2003-10-23 | 2005-05-19 | Nippon Oil Corp | Electric double layer capacitor, activated carbon for its electrode, and method of producing the carbon |
| JP2005129707A (en) * | 2003-10-23 | 2005-05-19 | Nippon Oil Corp | Electric double layer capacitor, activated carbon for its electrode, and method of producing the carbon |
| JP2008120610A (en) * | 2006-11-09 | 2008-05-29 | Sumitomo Chemical Co Ltd | Activated carbon and method for producing the same |
| JP2008181949A (en) * | 2007-01-23 | 2008-08-07 | Hitachi Chem Co Ltd | Electrode material for electric double-layer capacitor and the electric double-layer capacitor |
Non-Patent Citations (1)
| Title |
|---|
| JPN6013032176; 炭素材料学会編: 活性炭-基礎と応用 第３版, 19780901, Ｐ．８０〜８１, 株式会社講談社 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012028668A (en) * | 2010-07-27 | 2012-02-09 | Air Water Inc | Coated electrode and capacitor using it |
| KR101137719B1 (en) * | 2010-12-07 | 2012-04-24 | 한국세라믹기술원 | Manufacturing method of active carbon electrode for supercapacitor |
| JP2015154039A (en) * | 2014-02-19 | 2015-08-24 | 住友電気工業株式会社 | Capacitor and charge and discharge method thereof |
| WO2015125594A1 (en) * | 2014-02-19 | 2015-08-27 | 住友電気工業株式会社 | Capacitor and method for charging and discharging same |
| KR20160027810A (en) * | 2014-09-02 | 2016-03-10 | 한국전기연구원 | Carbon material vertical surface treatment apparatus |
| KR101668308B1 (en) * | 2014-09-02 | 2016-10-21 | 한국전기연구원 | Carbon material vertical surface treatment apparatus |
| WO2016122070A1 (en) * | 2015-01-29 | 2016-08-04 | 한국전기연구원 | Method for modifying carbon material electrode surface by current carrying, surface-modified carbon material electrode, and electrochemical capacitor comprising surface-modified carbon material electrode |
| JP2017076767A (en) * | 2015-10-15 | 2017-04-20 | ジーエス エナジー コーポレーション | Active carbon for electric double-layer capacitor electrode and manufacturing method of the same |
| JP2017088443A (en) * | 2015-11-09 | 2017-05-25 | 住友電気工業株式会社 | Porous carbon material, manufacturing method, and electrode and capacitor using the same |
| CN105399095A (en) * | 2015-12-28 | 2016-03-16 | 大连理工大学 | Apparatus and method for preparing high specific surface area active carbon through alkali activation process |
| CN105399095B (en) * | 2015-12-28 | 2018-05-08 | 大连理工大学 | A kind of device and method that active carbon with high specific surface area is prepared for alkali activation method |
| WO2022174335A1 (en) * | 2021-02-17 | 2022-08-25 | Supercap Technologies Corp. | Sweeping gas process for production of activated carbon-based electrode materials |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5676074B2 (en) | 2015-02-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5676074B2 (en) | Method for reforming activated carbon | |
| JP5271851B2 (en) | Method for producing activated carbon and electric double layer capacitor using activated carbon obtained by the method | |
| CN102460620B (en) | Carbon material for electric double layer capacitor electrode and method for producing same | |
| JP5027849B2 (en) | Method for producing activated carbon, and electric double layer capacitor using activated carbon obtained by the method | |
| Rustamaji et al. | Urea nitrogenated mesoporous activated carbon derived from oil palm empty fruit bunch for high-performance supercapacitor | |
| CN1769165A (en) | Carbons useful in energy storage devices | |
| US10008337B2 (en) | Activated carbon for an electric double-layer capacitor electrode and manufacturing method for same | |
| JP2017208444A (en) | Method of producing modified activated carbon | |
| KR20120091383A (en) | Activated carbon for electric double-layer capacitor electrode and method for producing the same | |
| JP2012101948A (en) | Method for producing activated carbon | |
| TWI760334B (en) | Carbonaceous material, method for producing the same, and electrode material for electric double layer capacitor, electrode for electric double layer capacitor, and electric double layer capacitor containing the carbonaceous material | |
| US20180212229A1 (en) | High specific surface area hard carbon-based electrode active material through carbonization process control and electrode active material by thereof | |
| US20200308006A1 (en) | Carbonaceous material and method for producing same | |
| TWI751290B (en) | Carbonaceous material and its manufacturing method, and electrode material for electric double layer capacitor, electrode for electric double layer capacitor and electric double layer capacitor containing the carbon material | |
| KR20190120757A (en) | Carbonaceous Material and Manufacturing Method Thereof | |
| JP2003282369A (en) | Carbon material for electric double-layer capacitor and its manufacturing method | |
| JP2007221108A (en) | Active carbon and method for fabrication thereof | |
| JP2007112704A (en) | Activated carbon, its manufacturing method and polarizable electrode and electric double-layer capacitor using the activated carbon | |
| KR101653488B1 (en) | Preparation of steam-activated carbon by polymeric precursor | |
| JP5563239B2 (en) | Method for producing porous carbon material | |
| JP2002083747A (en) | Activated carbon for electrode of electric double-layer capacitor | |
| JP5481073B2 (en) | Manufacturing method of highly purified activated carbon | |
| JP2010215474A (en) | Producing method of active carbon and electrical double layer capacitor using active carbon obtained by the method | |
| JP4615868B2 (en) | Method for producing porous carbon for electric double layer capacitor, porous carbon for electric double layer capacitor obtained by the production method, and electric double layer capacitor using porous carbon for electric double layer capacitor | |
| JP3884060B1 (en) | Electric field activation method for electric double layer capacitor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20111020 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20130104 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20130702 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20130902 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20140408 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20140609 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20141216 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20141225 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5676074 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |