JP2020009847A - Active carbon for electric double layer capacitor, electric double layer capacitor, manufacturing methods thereof, and electrode for electric double layer capacitor - Google Patents

Active carbon for electric double layer capacitor, electric double layer capacitor, manufacturing methods thereof, and electrode for electric double layer capacitor Download PDF

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JP2020009847A
JP2020009847A JP2018127995A JP2018127995A JP2020009847A JP 2020009847 A JP2020009847 A JP 2020009847A JP 2018127995 A JP2018127995 A JP 2018127995A JP 2018127995 A JP2018127995 A JP 2018127995A JP 2020009847 A JP2020009847 A JP 2020009847A
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double layer
electric double
activated carbon
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孝 廣瀬
Takashi Hirose
孝 廣瀬
直人 岩野
Naoto Iwano
直人 岩野
拓朗 波間
Takuro Namima
拓朗 波間
一志 永原
Kazushi Nagahara
一志 永原
山口 敦
Atsushi Yamaguchi
敦 山口
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Elna Co Ltd
Aomori Prefectural Industrial Technology Research Center
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Elna Co Ltd
Aomori Prefectural Industrial Technology Research Center
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    • YGENERAL 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
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    • Y02E60/13Energy storage using capacitors

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Abstract

To provide an active carbon for an electric double layer capacitor by using pruned branches of an apple tree which are a waste.SOLUTION: An active carbon for an electric double layer capacitor has a basic configuration as follows. The active carbon involves micro pores of 0.65 to 0.70 nm in pore diameter, which account for 24.9% of all of micro pores or more. As a raw material of the active carbon, a tree branch such as an apple tree pruned branch can be used suitably. Using, as a raw material, apple tree pruned branches, which are a waste in cultivation of apples, leads to the decrease in waste, and effective utilization of the waste. Particularly in the case of the active carbon for an electric double layer capacitor according to the invention, pellets arranged by using tree branches, especially apple tree pruned branches as a raw material can be used as a starting raw material.SELECTED DRAWING: None

Description

本発明は、特に樹木枝を利用した活性炭とその製造技術に係り、特に、電気二重層コンデンサ用活性炭の新しい製造技術等に関するものである。   The present invention particularly relates to activated carbon utilizing tree branches and its production technology, and more particularly to a new production technology of activated carbon for electric double layer capacitors.

高比表面積かつ細孔の多い多機能材料である活性炭は、主にヤシガラや木材等を原料として、炭素化・賦活の二段階処理により製造される。賦活処理には、〈1〉炭素化によって得られた炭素質を熱処理する過程でガス等を注入するガス賦活法、〈2〉出発原料または炭素化物に塩化亜鉛等を含浸後、熱処理する薬品賦活法 の二つがある。前者は、炭素化された原料を高温で水蒸気、炭酸ガス、酸素、その他の酸化ガス等と接触反応させて微細な多孔質炭素質吸着剤を製造する方法である。一方、後者は、原料に塩化亜鉛等を含浸して焼成することで炭素質を侵食して脱水酸化、炭素化温度を低下させ、吸着機能を発現させる方法だが、製造プロセスおよび製造コスト負担がより大きい。   Activated carbon, which is a multifunctional material having a high specific surface area and a large number of pores, is produced mainly by using coconut husk, wood, or the like as a raw material by a two-stage treatment of carbonization and activation. The activation treatment includes (1) a gas activation method in which a gas or the like is injected in a process of heat-treating carbonaceous material obtained by carbonization, and (2) a chemical activation in which a starting material or a carbonized material is impregnated with zinc chloride or the like and then heat-treated. There are two laws. The former is a method of producing a fine porous carbonaceous adsorbent by contacting a carbonized raw material with steam, carbon dioxide, oxygen, other oxidizing gases, or the like at a high temperature. On the other hand, the latter is a method of impregnating the carbonaceous material by impregnating the raw material with zinc chloride etc. and firing it, dehydrating, lowering the carbonization temperature, and expressing the adsorption function, but the production process and production cost burden are more large.

ところで、木材中の微量元素(金属、非金属元素)は、空気賦活時に触媒的な作用によってガス化反応を促進すると考えられており、木材を炭素化処理する際には賦活を促進する効果が期待できる。特に枝には、幹の7〜10倍程度の微量元素が含有されており、シダレヤナギ、ケヤキ・サクラ等の枝を原料とする高比表面積の活性炭製造技術等が開示されている(後掲特許文献1)。   By the way, trace elements (metals and non-metallic elements) in wood are considered to promote the gasification reaction by catalytic action at the time of air activation, and when wood is carbonized, the effect of promoting the activation is considered. Can be expected. In particular, the branches contain about 7 to 10 times the amount of trace elements of the trunk, and a technique for producing a high specific surface area activated carbon using branches of weeping willow, zelkova, sakura, etc. as a raw material has been disclosed (the patents listed below). Reference 1).

さて、世界的なリンゴ産地である青森県では、リンゴ園管理において伐られた枝(以下「リンゴ剪定枝」)が廃材として大量に産出されており、その有効利用が求められている。これを用いて、薬品賦活法のような製造プロセスおよび製造コストをかけることなくより簡易に、優れた性能を備えた活性炭を製造できれば、農業分野、活性炭・吸着材等の製造分野双方にメリットがある。かかる着眼に基づいて先に本願発明者は、原料としてリンゴ剪定枝のみを利用し、薬品賦活を用いることなく簡易なプロセスによって得られる、大きな比表面積と細孔容積、およびメソ孔(直径2〜50nmの孔)を多く有する活性炭の製造方法を発明し、開示した(特許文献1)。   Now, in Aomori Prefecture, a world-wide apple production area, branches cut in apple orchard management (hereinafter referred to as "apple pruned branches") are produced in large quantities as waste materials, and their effective use is required. If activated carbon with excellent performance can be easily and simply manufactured without using the production process and production cost such as the chemical activation method using this, there are advantages in both the agricultural field and the manufacturing fields of activated carbon and adsorbents. is there. Based on this viewpoint, the inventor of the present application first utilized the apple pruned branch as a raw material, and obtained a large specific surface area, a fine pore volume, and a mesopore (diameter of 2 to 2) obtained by a simple process without using chemical activation. A method for producing activated carbon having many (50 nm pores) was invented and disclosed (Patent Document 1).

本願発明者はまた、メソ孔容積の大きい活性炭における高い吸湿性能を製造プロセスによって制御することを目的として、下記[1]〜[12]の発明を完成し、特許出願した(特許文献2)。これらにより、メソ孔容積等の細孔特性を製造方法により制御し、吸湿性能の調節や用途に応じた吸湿性能の付与でき、製品開発を容易ならしめ、かつ拡大できるようになった。
[1] 炭素化原料が炭素化処理されてなる炭素化物を賦活処理過程に供して活性炭を得る活性炭製造方法であって、該賦活処理過程における賦活処理条件を調節することにより得られる活性炭の収率を調節し、それによって活性炭の細孔の特性を制御することを特徴とする、活性炭製造方法。
[2] 前記細孔の特性が比表面積、ミクロ孔(直径2nm以下の孔)容積、メソ孔(直径2〜50nmの孔)容積、または細孔直径分布の少なくともいずれかであることを特徴とする、[1]に記載の活性炭製造方法。
[3] 前記賦活処理条件は賦活処理時間であることを特徴とする、[1]または[2]に記載の活性炭製造方法。
[4] 前記賦活処理時間を長くすることによって前記収率を下げ、それにより前記細孔の容積を大きくすることを特徴とする、[3]に記載の活性炭製造方法。
[5] 前記賦活処理時間を長くすることによって前記収率を下げ、それにより前記細孔の直径を大きくすることを特徴とする、[3]に記載の活性炭製造方法。
[6] 前記細孔がメソ孔であることを特徴とする、[5]に記載の活性炭製造方法。
[7] 前記賦活処理時間を長くすることによって前記収率を下げ、それにより前記比表面積を大きくすることを特徴とする、[3]に記載の活性炭製造方法。
[8] 賦活処理時間または収率と細孔特性との関係を予め求めておき、賦活処理時間または収率の設定によって所望の細孔特性を得ることを特徴とする、[3]に記載の活性炭製造方法。
[9] 得られる活性炭がペレット状であることを特徴とする、[1]ないし[8]のいずれかに記載の活性炭製造方法。
[10] 前記炭素化原料は樹木枝であることを特徴とする、[1]ないし[9]のいずれかに記載の活性炭製造方法。
[11] 前記炭素化原料はリンゴ剪定枝であることを特徴とする、[1]ないし[9]のいずれかに記載の活性炭製造方法。
[12〕 ペレット状の炭素化原料から前記炭素化物を得る炭素化処理過程を備えることを特徴とする、[1]ないし[11]のいずれかに記載の活性炭製造方法。
The inventor of the present application completed the inventions [1] to [12] described below and applied for a patent for the purpose of controlling high moisture absorption performance of activated carbon having a large mesopore volume by a production process (Patent Document 2). Thus, the pore characteristics such as the mesopore volume can be controlled by the manufacturing method, and the moisture absorption performance can be adjusted and the moisture absorption performance can be imparted according to the application, thereby facilitating and expanding the product development.
[1] A method for producing activated carbon in which a carbonized material obtained by subjecting a carbonization raw material to carbonization is subjected to an activation treatment process to obtain activated carbon, and the yield of activated carbon obtained by adjusting the activation treatment conditions in the activation treatment process. A method for producing activated carbon, comprising adjusting the rate and thereby controlling the properties of the pores of the activated carbon.
[2] The characteristics of the pores are at least one of specific surface area, volume of micropores (pores having a diameter of 2 nm or less), volume of mesopores (pores having a diameter of 2 to 50 nm), and pore diameter distribution. The method for producing activated carbon according to [1].
[3] The activated carbon production method according to [1] or [2], wherein the activation treatment condition is an activation treatment time.
[4] The method for producing activated carbon according to [3], wherein the yield is lowered by extending the activation treatment time, thereby increasing the volume of the pores.
[5] The method for producing activated carbon according to [3], wherein the yield is reduced by lengthening the activation treatment time, thereby increasing the diameter of the pores.
[6] The method for producing activated carbon according to [5], wherein the pores are mesopores.
[7] The method for producing activated carbon according to [3], wherein the yield is reduced by lengthening the activation treatment time, thereby increasing the specific surface area.
[8] The method according to [3], wherein a relationship between the activation time or the yield and the pore characteristics is determined in advance, and desired pore characteristics are obtained by setting the activation time or the yield. Activated carbon production method.
[9] The method for producing activated carbon according to any one of [1] to [8], wherein the obtained activated carbon is in the form of pellets.
[10] The method for producing activated carbon according to any one of [1] to [9], wherein the carbonization raw material is a tree branch.
[11] The method for producing activated carbon according to any one of [1] to [9], wherein the carbonized raw material is apple pruned branches.
[12] The method for producing activated carbon according to any one of [1] to [11], further comprising a carbonization treatment step of obtaining the carbonized product from a pelletized carbonized raw material.

特許第5935039号公報「活性炭製造方法」Patent No. 5935039, "Method for producing activated carbon" 特願2017−040024号公報「活性炭製造方法」(本願出願時に未公開)Japanese Patent Application No. 2017-040024, "Method for producing activated carbon" (not disclosed at the time of filing the present application)

上述の通り本願発明者は、主として樹木枝を活用した活性炭製造技術について成果を上げてきた。並行して、これらの成果に基づき各用途における製品開発のための研究も進めており、特に、電気二重層コンデンサ用として最適な活性炭の製造技術に取り組んできた。電気二重層とは、荷電粒子が比較的自由に動ける系に対して電位が与えられた際の荷電粒子移動の結果、界面に正負の荷電粒子が対を形成して層状に並ぶ現象であるが、これを利用することにより蓄電量を著しく高めたコンデンサが、電気二重層コンデンサである。電気二重層コンデンサは、活性炭等の多孔質炭素電極と電解液を備えて構成されるが、活性炭の細孔と電解液の界面に電気二重層が形成され、これに電荷が蓄えられる原理である。大電流充放電が可能であり、長寿命に加えて高温安定性にも優れるため、注目度が高い。   As described above, the inventor of the present application has mainly achieved results on activated carbon production technology utilizing tree branches. At the same time, based on these results, we are also conducting research on product development for each application, and we have been working on the most appropriate activated carbon production technology for electric double layer capacitors. The electric double layer is a phenomenon in which positive and negative charged particles form pairs at the interface and line up in layers as a result of charged particle movement when a potential is applied to a system in which charged particles can move relatively freely. An electric double-layer capacitor is a capacitor whose power storage amount is significantly increased by utilizing this. An electric double layer capacitor is configured to include a porous carbon electrode such as activated carbon and an electrolytic solution. The principle is that an electric double layer is formed at the interface between the pores of the activated carbon and the electrolytic solution, and charges are stored in the electric double layer. . It can be charged and discharged with a large current and has high stability at high temperatures in addition to long life.

そこで本発明が解決しようとする課題は、かかる従来技術を踏まえ、電気二重層コンデンサ用として適した特性を有する活性炭とその製造方法を提供することであり、また、電気二重層コンデンサならびにその製造方法、および電気二重層コンデンサ用電極を提供することである。さらに本発明の課題は、廃棄物であるリンゴ剪定枝を用いて電気二重層コンデンサ用として適した特性を有する活性炭とその製造方法を提供することであり、また、電気二重層コンデンサならびにその製造方法、および電気二重層コンデンサ用電極を提供することである。   The problem to be solved by the present invention is to provide an activated carbon having characteristics suitable for use in an electric double layer capacitor and a method for producing the same, based on the prior art, and an electric double layer capacitor and a method for producing the same. , And an electrode for an electric double layer capacitor. Still another object of the present invention is to provide an activated carbon having characteristics suitable for an electric double layer capacitor using apple pruned branches as waste and a method for producing the same, and an electric double layer capacitor and a method for producing the same. , And an electrode for an electric double layer capacitor.

本願発明者は上記課題について検討した結果、その解決手段を見出し、本発明を完成するに至った。すなわち、上記課題を解決するための手段として本願で特許請求される発明、もしくは少なくとも開示される発明は、以下の通りである。
〔1〕 孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれていることを特徴とする、電気二重層コンデンサ用活性炭。
〔2〕 原料が樹木枝であることを特徴とする、〔1〕に記載の電気二重層コンデンサ用活性炭。
〔3〕 原料がリンゴ剪定枝であることを特徴とする、〔1〕、または〔2〕に記載の電気二重層コンデンサ用活性炭。
〔4〕 樹木枝またはリンゴ剪定枝を原料としたペレットを出発原料としてミクロ孔分布が調整されていることを特徴とする、〔1〕ないし〔3〕のいずれかに記載の電気二重層コンデンサ用活性炭。
〔5〕 孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれるように調整される過程を備えることを特徴とする、電気二重層コンデンサ用活性炭製造方法。
As a result of studying the above problems, the present inventor has found a means for solving the problems, and has completed the present invention. That is, the invention claimed in the present application as a means for solving the above-mentioned problem, or at least the disclosed invention is as follows.
[1] Activated carbon for an electric double layer capacitor, wherein micropores having a pore size of 0.65 nm or more and 0.70 nm or less are contained in a ratio of 24.9% or more of all the micropores.
[2] The activated carbon for electric double layer capacitors according to [1], wherein the raw material is a tree branch.
[3] The activated carbon for electric double layer capacitors according to [1] or [2], wherein the raw material is apple pruned branches.
[4] The electric double layer capacitor according to any one of [1] to [3], wherein the micropore distribution is adjusted using pellets made from tree branches or apple pruned branches as starting materials. Activated carbon.
[5] For an electric double layer capacitor, characterized by comprising a process of adjusting so that micropores having a pore size of 0.65 nm or more and 0.70 nm or less are included in a quantitative ratio of 24.9% or more of all micropores. Activated carbon production method.

〔6〕 樹木枝を原料としたペレットを出発原料とすることを特徴とする、〔5〕に記載の電気二重層コンデンサ用活性炭製造方法。
〔7〕 リンゴ剪定枝を原料としたペレットを出発原料とすることを特徴とする、〔5〕に記載の電気二重層コンデンサ用活性炭製造方法。
〔8〕 原料活性炭の賦活処理過程を、供する炭化物(賦活処理前)の粒子サイズ、処理量(投入量)、窒素ガス流通量、水蒸気流通量、設定最高到達温度、賦活処理時間の各処理条件のうち、少なくともいずれか一つの条件を特定させた賦活処理過程とすることを特徴とする、〔5〕ないし〔7〕のいずれかに記載の電気二重層コンデンサ用活性炭製造方法。
〔9〕 賦活処理過程における他の条件を固定した上で最適なミクロ孔分布が得られる賦活処理時間をあらかじめ試験しておき、それによって特定される賦活処理時間を条件として用いて製造することを特徴とする、〔5〕ないし〔8〕のいずれかに記載の電気二重層コンデンサ用活性炭製造方法。
〔10〕 〔1〕ないし〔4〕のいずれかに記載の電気二重層コンデンサ用活性炭、または〔5〕ないし〔9〕のいずれかに記載の電気二重層コンデンサ用活性炭製造方法により製造される電気二重層コンデンサ用活性炭を用いていることを特徴とする、電気二重層コンデンサ用電極。
〔11〕 〔1〕ないし〔4〕のいずれかに記載の電気二重層コンデンサ用活性炭、または〔5〕ないし〔9〕のいずれかに記載の電気二重層コンデンサ用活性炭製造方法により製造される電気二重層コンデンサ用活性炭を用いていることを特徴とする、電気二重層コンデンサ。
〔12〕 〔1〕ないし〔4〕のいずれかに記載の電気二重層コンデンサ用活性炭、または〔5〕ないし〔9〕のいずれかに記載の電気二重層コンデンサ用活性炭製造方法を用いて製造することを特徴とする、電気二重層コンデンサ製造方法。
[6] The method for producing activated carbon for an electric double layer capacitor according to [5], wherein pellets made from tree branches are used as a starting material.
[7] The method for producing activated carbon for an electric double layer capacitor according to [5], wherein a pellet made from apple pruned branches is used as a starting material.
[8] In the process of activating the raw material activated carbon, various processing conditions such as the particle size, treatment amount (input amount), nitrogen gas circulation amount, steam circulation amount, set maximum attainment temperature, and activation treatment time of the carbide (before activation treatment) to be provided The method for producing activated carbon for an electric double layer capacitor according to any one of [5] to [7], wherein the activation treatment step specifies at least one of the conditions.
[9] It is necessary to preliminarily test an activation treatment time at which an optimum micropore distribution is obtained after fixing other conditions in the activation treatment process, and to manufacture using the activation treatment time specified thereby as a condition. The method for producing activated carbon for an electric double layer capacitor according to any one of [5] to [8].
[10] Activated carbon for an electric double layer capacitor according to any of [1] to [4], or electricity produced by the method for producing activated carbon for an electric double layer capacitor according to any of [5] to [9] An electrode for an electric double layer capacitor, characterized by using activated carbon for a double layer capacitor.
[11] Activated carbon for an electric double layer capacitor according to any one of [1] to [4], or electricity produced by the method for producing activated carbon for an electric double layer capacitor according to any of [5] to [9] An electric double layer capacitor characterized by using activated carbon for a double layer capacitor.
[12] The active carbon for an electric double layer capacitor according to any of [1] to [4], or the activated carbon for an electric double layer capacitor according to any of [5] to [9]. A method for manufacturing an electric double layer capacitor, comprising:

本発明の電気二重層コンデンサ用活性炭、電気二重層コンデンサ、ならびにそれらの製造方法、および電気二重層コンデンサ用電極は上述のように構成されるため、これらによれば、電気二重層コンデンサ用として適した特性を有する活性炭や電気二重層コンデンサ用電極を提供することができる。特に、収率と比表面積、ミクロ孔容積およびメソ孔容積とが高い相関を示すという新たな知見により、ミクロ孔分布を調整することで電気二重層コンデンサ用として適した特性を有する活性炭や電気二重層コンデンサ用電極を提供することができる。さらに本発明によれば、廃棄物であるリンゴ剪定枝を有効活用して、電気二重層コンデンサ用として適した特性を有する活性炭や電気二重層コンデンサ用電極を提供することができ、廃棄物たるリンゴ剪定枝に関し廃棄量の削減に寄与し、有効活用することができる。   The activated carbon for an electric double layer capacitor, the electric double layer capacitor, the method for producing the same, and the electrode for the electric double layer capacitor of the present invention are configured as described above. Activated carbon and an electrode for an electric double layer capacitor having excellent characteristics can be provided. In particular, new knowledge that the yield and specific surface area, micropore volume and mesopore volume show a high correlation shows that activated carbon or electric carbon having characteristics suitable for electric double layer capacitors by adjusting the micropore distribution. An electrode for a multilayer capacitor can be provided. Further, according to the present invention, it is possible to provide an activated carbon or an electrode for an electric double layer capacitor having characteristics suitable for an electric double layer capacitor by effectively utilizing apple pruned branches as waste, and to produce apple as a waste. It contributes to the reduction of waste amount of pruned branches and can be used effectively.

活性炭の収率とかさ密度との関係を示すグラフである。It is a graph which shows the relationship between the yield of activated carbon, and a bulk density. 活性炭の収率と比表面積との関係を示すグラフである。It is a graph which shows the relationship between the yield of activated carbon, and a specific surface area. 活性炭の収率とミクロ孔容積との関係を示すグラフである。It is a graph which shows the relationship between the yield of activated carbon, and micropore volume. 活性炭の収率とメソ孔容積との関係を示すグラフである。It is a graph which shows the relationship between the yield of activated carbon, and mesopore volume. 電気二重層コンデンサ用活性炭のミクロ孔分布を示すグラフである。It is a graph which shows the micropore distribution of activated carbon for electric double layer capacitors. 電気二重層コンデンサ用活性炭のメソ孔分布を示すグラフである。It is a graph which shows the mesopore distribution of the activated carbon for electric double layer capacitors. 時間と静電容量との関係を示すグラフである。It is a graph which shows the relationship between time and capacitance. 時間と内部抵抗との関係を示すグラフである。(図1〜8は、実施例1に係る各図である。)5 is a graph showing a relationship between time and internal resistance. (FIGS. 1 to 8 are diagrams according to the first embodiment.) 電極当たりのミクロ孔分布を示すグラフである。It is a graph which shows the micropore distribution per electrode. 0.5〜0.9nmの電極当たりのミクロ孔分布を示すグラフである。5 is a graph showing the distribution of micropores per electrode from 0.5 to 0.9 nm. 電極当たりのメソ孔分布を示すグラフである。It is a graph which shows the mesopore distribution per electrode. 1〜10nmの電極当たりのメソ孔分布を示すグラフである。It is a graph which shows the mesopore distribution per electrode of 1-10 nm. 電極当たりのミクロ孔分布を示すグラフである。It is a graph which shows the micropore distribution per electrode. 0.5〜0.9nmの電極当たりのミクロ孔分布を示すグラフである。5 is a graph showing the distribution of micropores per electrode from 0.5 to 0.9 nm. 電極当たりのメソ孔分布を示すグラフである。It is a graph which shows the mesopore distribution per electrode. 1〜10nmの電極当たりのメソ孔分布を示すグラフである。(図9〜16は、実施例2に係る各図である。)It is a graph which shows the mesopore distribution per electrode of 1-10 nm. (FIGS. 9 to 16 are diagrams according to the second embodiment.)

以下、本発明をより詳細に説明する。
まず、本発明に係る電気二重層コンデンサ用活性炭の基本的構成は、孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれていることである。また、活性炭の原料としては、リンゴ剪定枝等の樹木枝を好適に用いることもできる。リンゴ栽培における廃棄物であるリンゴ剪定枝を原料とする場合、廃棄物削減、廃棄物有効利用に繋がる。実施例に後述するように本発明電気二重層コンデンサ用活性炭は特に、樹木枝またはリンゴ剪定枝を原料としたペレットを出発原料とすることができる。しかしながら、本発明活性炭はこれに限定されず、従来公知の原料を用いたもの、あるいは市販の活性炭を原料としたものであってもよい。
Hereinafter, the present invention will be described in more detail.
First, the basic configuration of the activated carbon for an electric double layer capacitor according to the present invention is that micropores having a pore size of 0.65 nm or more and 0.70 nm or less are contained at a ratio of 24.9% or more of all the micropores. is there. Further, as a raw material of the activated carbon, a tree branch such as an apple pruned branch can be suitably used. When apple pruned branches, which are waste in apple cultivation, are used as raw materials, this leads to waste reduction and effective waste utilization. As will be described later in the examples, the activated carbon for an electric double layer capacitor of the present invention can use, in particular, pellets made from tree branches or apple pruned branches as starting materials. However, the activated carbon of the present invention is not limited thereto, and may be one using a conventionally known raw material or one using a commercially available activated carbon as a raw material.

また、本発明の電気二重層コンデンサ用活性炭製造方法は、孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれるように調整される過程を有することを、特徴的な構成とする。本発明製法に用いる原料としては、上述の通り、廃棄物有効利用および産生量削減の観点から、樹木枝、特にはリンゴ剪定枝を原料としたペレットを出発原料とすることができる。もちろん、出発原料はこれに限定されない。特に実施例に後述するように、市販の活性炭に本発明特有の処理を施すことによって、電気二重層コンデンサ用として適した特性を有する活性炭を製造することが可能である。   The method for producing activated carbon for an electric double layer capacitor according to the present invention includes a process in which micropores having a pore diameter of 0.65 nm or more and 0.70 nm or less are adjusted so as to be contained in a ratio of 24.9% or more of all the micropores. Having a characteristic configuration. As a raw material used in the production method of the present invention, as described above, from the viewpoint of effective use of waste and reduction of production amount, pellets made from tree branches, particularly apple pruned branches, can be used as starting materials. Of course, the starting material is not limited to this. In particular, as will be described later in Examples, it is possible to produce an activated carbon having characteristics suitable for an electric double layer capacitor by subjecting a commercially available activated carbon to a treatment unique to the present invention.

かかるミクロ孔の具体的な調整方法は、実施例に後述するように、所定の賦活処理過程における賦活処理条件の設定によって行なうことができる。つまり、原料活性炭の賦活処理における、供する炭化物(賦活前)の粒子サイズ、処理量(投入量)、窒素ガス流通量、水蒸気流通量、設定最高到達温度、賦活処理時間といった処理条件のうち、少なくともいずれか一つの条件を特定させた賦活処理過程とすることで、孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれるように調整することができる。   A specific method for adjusting the micropores can be performed by setting activation processing conditions in a predetermined activation processing step, as described later in Examples. That is, in the activation treatment of the raw material activated carbon, at least one of the processing conditions such as the particle size of the carbide to be provided (before activation), the treatment amount (input amount), the nitrogen gas circulation amount, the steam circulation amount, the set maximum reaching temperature, and the activation treatment time. By performing the activation process in which any one of the conditions is specified, the micropores having a pore diameter of 0.65 nm or more and 0.70 nm or less are adjusted so as to be included in a quantity ratio of 24.9% or more of all the micropores. Can be.

たとえば、原料活性炭の賦活処理における、供する炭化物(賦活前)の粒子サイズ、処理量(投入量)、窒素ガス流通量、水蒸気流通量、設定最高到達温度、賦活処理時間の全てを特定させた賦活処理過程としてもよいし、一方、窒素ガス流通量・水蒸気流通量・設定最高到達温度・賦活処理時間を特定させる過程、設定細孔到達温度・賦活処理時間を特定させる過程、賦活処理時間のみを特定させる過程、その他如何なる特定の仕方であっても、本発明の範囲内である。   For example, in the activation treatment of the raw material activated carbon, activation in which all of the particle size, treatment amount (input amount), nitrogen gas circulation amount, steam circulation amount, set maximum attainment temperature, and activation treatment time of the provided carbide (before activation) are specified The process may be a process, or, on the other hand, a process of specifying a nitrogen gas flow rate, a steam flow rate, a set maximum attainment temperature, and an activation time, a process of specifying a set pore attainment temperature and an activation time, and only the activation time. The process of specifying, and any other specific manner, is within the scope of the present invention.

しかしながら、電気二重層コンデンサ用活性炭としての適性としてそのミクロ孔分布の構成を左右するのは、賦活処理における目標収率、あるいは収率である。そして、かかる目標収率あるいは収率は、賦活処理時間の長短により調整することができる。したがって、賦活処理過程における他の条件を固定した上で最適なミクロ孔分布が得られる賦活処理時間をあらかじめ試験しておき、それによって特定される賦活処理時間を条件として用いて、電気二重層コンデンサ用活性炭を製造することとすればよい。   However, it is the target yield or yield in the activation treatment that determines the composition of the micropore distribution as the suitability as activated carbon for electric double layer capacitors. The target yield or the yield can be adjusted depending on the length of the activation treatment time. Therefore, an activation treatment time at which an optimum micropore distribution is obtained after fixing other conditions in the activation treatment process is tested in advance, and the activation treatment time specified thereby is used as a condition, and the electric double layer capacitor is used. Activated carbon may be produced.

なお、樹木枝やリンゴ剪定枝、市販の活性炭、その他用いる原料によって、電気二重層コンデンサ用活性炭として適する特性が得られる目標収率(あるいは収率)・賦活処理時間は一定ではないが、予め試験を行なうことでこれは容易に特定することができる。   Note that the target yield (or yield) and activation treatment time at which characteristics suitable as activated carbon for electric double layer capacitors can be obtained depending on tree branches, apple pruned branches, commercially available activated carbon, and other raw materials used are not constant, but are not tested beforehand. This can be easily specified.

なお、以上説明したいずれかの構成の電気二重層コンデンサ用活性炭、または以上説明したいずれかの電気二重層コンデンサ用活性炭製造方法により製造される電気二重層コンデンサ用活性炭を用いて構成される電気二重層コンデンサ用電極や電気二重層コンデンサ、および、以上説明したいずれかの構成の電気二重層コンデンサ用活性炭を用いる電気二重層コンデンサ製造方法もまた、本発明の範囲内である。   It should be noted that the activated carbon for an electric double layer capacitor having any of the above-described structures, or the electric carbon configured using the activated carbon for an electric double layer capacitor manufactured by any of the above-described methods for producing an activated carbon for an electric double layer capacitor. The method for manufacturing an electrode for a multilayer capacitor, an electric double layer capacitor, and a method for manufacturing an electric double layer capacitor using activated carbon for an electric double layer capacitor having any of the above-described configurations is also within the scope of the present invention.

以下、本発明の実施例を説明するが、本発明がこれに限定されるものではない。なお、本発明の完成に至る研究経過の説明をもって実施例とする。
<実施例1>
実験方法
1.1 コンデンサ用活性炭の調製
1.1.1 ペレットの調製
原料として、リンゴ剪定枝をハンマークラッシャーでチップ化し、篩にかけた10mm以下のものを用いた。ペレット化は、ペレタイザー(アースエンジニアリング社製、EF−BS−150)を用いて、原料供給100kg/時、回転数60回/分、目標直径を4mmとして調製した。
Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. The description of the progress of the research leading to the completion of the present invention will be described as an example.
<Example 1>
Experimental Method 1.1 Preparation of Activated Carbon for Capacitor 1.1.1 Preparation of Pellet As a raw material, a pruned apple branch was chipped with a hammer crusher and sieved to 10 mm or less. Pelletization was performed using a pelletizer (EF-BS-150, manufactured by Earth Engineering Co., Ltd.) with a raw material supply of 100 kg / hour, a rotation speed of 60 times / minute, and a target diameter of 4 mm.

1.1.2 活性炭の調製
原料として、1.1.1で調製したペレットを用いた。炭素化処理は、活性炭製造実験機(MET社製)を用いて、キルン容器に7400gのペレットを投入し、窒素ガス100L/minを流通させながら、最高到達温度850℃、保持時間0.5時間の条件にて3回行った。炭素化率:Y(%)は、105℃、24時間加熱後のペレットの質量:W(%)、および、105℃、24時間加熱後の炭素化物の質量:W(%)から、以下の(1)式より算出した。
=W/W×100 ・・・(1)
1.1.2 Preparation of activated carbon The pellets prepared in 1.1.1 were used as raw materials. In the carbonization treatment, 7400 g of pellets were charged into a kiln container using an activated carbon production experimental machine (manufactured by MET), and a maximum temperature of 850 ° C. and a holding time of 0.5 hour were passed while flowing 100 L / min of nitrogen gas. This was performed three times under the following conditions. The carbonization rate: Y c (%) is obtained from the mass of the pellet after heating at 105 ° C. for 24 hours: W t (%) and the mass of the carbonized product after heating at 105 ° C. for 24 hours: W c (%). , Calculated from the following equation (1).
Y c = W c / W t × 100 (1)

賦活処理は、炭素化と同じく活性炭製造実験機(MET社製)を用いて、炭素化処理した炭素化物(以下:A1)3回分を合わせ、そこから4200gをキルン容器に投入し、窒素ガス100L/min、水蒸気12mL/minを流通させながら、最高到達温度850℃の条件で行った。A1からの目標収率は、賦活時間を調整することで、80%、70%、50%、40%、30%(以下:A2、A3、A4、A5、A6)とした。   In the activation treatment, the same amount of carbonized carbonized material (hereinafter, A1) was used for three times by using an activated carbon production experimental device (manufactured by MET) as in the case of carbonization, and 4200 g of the mixture was put into a kiln container, and 100 L of nitrogen gas was added. / Min and 12 mL / min of water vapor, and the maximum temperature reached 850 ° C. The target yield from A1 was adjusted to 80%, 70%, 50%, 40%, and 30% (hereinafter, A2, A3, A4, A5, and A6) by adjusting the activation time.

1.1.3 活性炭の洗浄方法
酸洗浄は、JIS H 1345に準じて遊星ボールミル(伊藤製作所社製、MC−4A)で粉末化した活性炭2g、および、0.1mol/Lの塩酸(和光純薬工業社製、試薬特級)17mLを100mLのビーカーに入れ、1時間放置後に2分間煮沸、蒸留水で洗浄、ろ過して行った。A2から得られたコンデンサ用活性炭をB1、A3からをB2、A4からをB3、A5からをB4、A6からをB5とし、これらを電気二重層コンデンサ用活性炭試料とした。なお、活性炭A1からの試料調製、コンデンサ試験は行なわなかった。
炭素化物A1(収率28.5%)に対する上記各目標収率をもって賦活処理時間調整により調製した炭素化物A2〜A6と、A2〜A6の酸洗浄処理により得たコンデンサ用活性炭B1〜B5との関係、およびA1〜A6の実際の収率(括弧内に示す)は、下記の通りである。
A1 −> コンデンサ試験せず(28.5%)
A2 −> B1 (23.3%)
A3 −> B2 (19.9%)
A4 −> B3 (15.3%)
A5 −> B4 (12.6%)
A6 −> B5 (10.8%)
1.1.3 Activated carbon cleaning method Acid cleaning was performed using 2 g of activated carbon powdered with a planetary ball mill (MC-4A, manufactured by Ito Seisakusho) according to JIS H 1345, and 0.1 mol / L hydrochloric acid (Wako Pure). 17 mL of a reagent (manufactured by Yakuhin Kogyo Co., Ltd.) was placed in a 100 mL beaker, left for 1 hour, boiled for 2 minutes, washed with distilled water, and filtered. The activated carbon for capacitors obtained from A2 was B1, B3 from A3, B3 from A4, B4 from A5, and B5 from A6, which were used as activated carbon samples for electric double layer capacitors. The preparation of the sample from the activated carbon A1 and the capacitor test were not performed.
The carbonized products A2 to A6 prepared by adjusting the activation treatment time with the above target yields for the carbonized product A1 (yield 28.5%), and the activated carbon B1 to B5 for capacitors obtained by the acid washing treatment of A2 to A6. The relationships, and the actual yields of A1-A6 (shown in parentheses) are as follows.
A1-> No capacitor test (28.5%)
A2-> B1 (23.3%)
A3-> B2 (19.9%)
A4-> B3 (15.3%)
A5-> B4 (12.6%)
A6-> B5 (10.8%)

1.2 基本物性の評価
各活性炭の収率:YCa(%)は、105℃、24時間加熱後のA1の質量:W(g)、および、105℃、24時間加熱後の各活性炭の質量:W(g)から、以下の(2)式より求めた。
Ca=W/W×100 ・・・(2)
1.2 Evaluation of Basic Physical Properties Yield of each activated carbon: Y Ca (%) is mass of A1 after heating at 105 ° C. for 24 hours: W s (g), and activated carbon after heating at 105 ° C. for 24 hours. From the mass: W c (g) of the following formula (2).
Y Ca = W c / W s × 100 (2)

試料の直径は、ノギスを使用して、任意に選んだ3粒の活性炭の中央付近を測定した。かさ密度:B(g/cm)は、JIS Z 7302 に準じて空の測定容器の質量:m(g)、試料を満たした測定容器の質量:m(g)、測定容器の容積:V(cm)から、以下の式(3)より算出、同サンプルを3回試験した結果の平均より求めた。
=(m−m)/V×1000 ・・・(3)
The diameter of the sample was measured using a caliper near the center of three randomly selected activated carbons. The bulk density: B d (g / cm 3 ) is the mass of an empty measuring container: m 0 (g), the mass of the measuring container filled with the sample: m 1 (g), and the mass of the measuring container according to JIS Z 7302. The volume was calculated from the following formula (3) from V (cm 3 ), and the average was obtained from the results of three tests on the same sample.
B d = (m 1 −m 0 ) / V × 1000 (3)

洗浄前後の灰分:YAsh(%)は、活性炭1gを磁性皿に入れ、JIS K 1474に準じて105℃、24時間乾燥後の試料の重量:W(%)および加熱炉(いすゞ製作所社製、ETP−26K)で800℃、2時間加熱後の試料の重量:W(%)から、以下の(4)式より算出、3サンプルの結果の平均より求めた。
Ash=W/W×100 ・・・(4)
Ash before and after washing: Y Ash (%) was measured by placing 1 g of activated carbon in a magnetic dish and drying the sample after drying at 105 ° C. for 24 hours according to JIS K 1474: W m (%) and a heating furnace (Isuzu Seisakusho Co., Ltd.). Ltd., ETP-26K) at 800 ° C., for 2 hours the sample after heating by weight: from W a (%), the following (4) calculated from the equation was determined from the average of three samples result.
Y Ash = W a / W m × 100 (4)

1.3 細孔構造の評価
比表面積、細孔容積および分布は、比表面積/細孔分布測定装置(日本ベル社製、BELSORP−mini)を用いて算出した。試料は粉砕せずペレットの状態のものおよびコンデンサ用の活性炭B1〜B5粉末を用い、250℃、5時間脱気後に−196℃での窒素吸脱着等温線を測定、BET法により比表面積:SN(m/g)、MP法によりミクロ孔容積:VtN(cm/g)およびミクロ孔分布、BJH法によりメソ孔容積:ViN(cm/g)および微分メソ孔容積分布を算出、3サンプルの結果の平均より求めた。
1.3 Evaluation of Pore Structure The specific surface area, pore volume and distribution were calculated using a specific surface area / pore distribution measuring device (BELSORP-mini, manufactured by Bell Japan, Inc.). The sample was not pulverized, but was used in the form of pellets and activated carbon B1 to B5 powder for a capacitor. After degassing at 250 ° C. for 5 hours, a nitrogen adsorption / desorption isotherm at −196 ° C. was measured. (M 2 / g), micropore volume: VtN (cm 3 / g) and micropore distribution were calculated by the MP method, and mesopore volume: ViN (cm 3 / g) and differential mesopore volume distribution were calculated by the BJH method. It was determined from the average of the sample results.

1.4 コンデンサの作製および評価
コンデンサ用電極材として、B1〜B5にそれぞれバインダーとしてポリテトラフルオロエチレン(以下:PTFE)水分散剤、導電材としてケッチェンブラック(以下:KB)を、最終割合が91:3:6の質量割合になるように混合し、加水して混練後、150℃乾燥器に移して水分を除去した。デシケータ中で冷却後、3tの圧力を印加後に粉砕し、75μm〜250μmメッシュにて篩にかけ、造粒粉を作製した。この造粒粉を一定量採取し、打錠成形によって、厚さ650μm、直径12mmの電極に加工した。
1.4 Production and Evaluation of Capacitors As a capacitor electrode material, polytetrafluoroethylene (hereinafter, PTFE) water dispersant as a binder, Ketjen black (hereinafter, KB) as a conductive material for B1 to B5, respectively, and a final ratio of 91 were used. : 3: 6, water was added and kneaded, and the mixture was transferred to a 150 ° C. drier to remove water. After cooling in a desiccator, a pressure of 3 t was applied, and the mixture was pulverized and sieved with a mesh of 75 μm to 250 μm to produce granulated powder. A certain amount of the granulated powder was collected and processed into an electrode having a thickness of 650 μm and a diameter of 12 mm by tableting.

この電極をコンデンサセルのキャップとケースに導電性接着剤を使用して接着し、高温真空乾燥を行った。その後、グローブボックス内にて、電極に電解液を注液し、セパレータを電極間に挿入、ガスケットを組み込んで、ケースとキャップをかしめて電気二重層コンデンサを試作した。電解液には、市販のテトラエチルアンモニウムテトラフルオロボレートの炭酸プロピレン溶液を使用した。   This electrode was adhered to the cap and the case of the capacitor cell using a conductive adhesive, followed by high-temperature vacuum drying. Thereafter, an electrolytic solution was injected into the electrodes in a glove box, a separator was inserted between the electrodes, a gasket was incorporated, and a case and a cap were caulked to produce a prototype electric double layer capacitor. As the electrolytic solution, a commercially available propylene carbonate solution of tetraethylammonium tetrafluoroborate was used.

コンデンサの評価は、室温において、コインセルの静電容量、内部抵抗、漏れ電流特性を測定後、85℃、1.8V印加の耐久性試験に投入し、所定の時間毎に取り出して放電し、室温にて上述の三特性を測定してコンデンサ性能を評価した。静電容量の測定は、1.8Vの定電圧で30分間充電後、定電流放電し、1.4V〜0.7Vの電圧範囲から、q=CVの関係を用いて算出した。内部抵抗は、1kHzの周波数にて市販のLCRメータを用いて測定した。漏れ電流値は、1.8Vで30分間定電圧充電を行った後に測定した。また、比較例として、市販の電気二重層用活性炭(クラレケミカル社製、YP−50F)を用い、同様の方法で作製、評価した。   The capacitor was evaluated by measuring the capacitance, internal resistance, and leakage current characteristics of the coin cell at room temperature, and then putting the coin cell into a durability test at 85 ° C. and applying 1.8 V. The capacitor was taken out and discharged at predetermined time intervals. The above three characteristics were measured to evaluate the capacitor performance. The capacitance was measured by charging at a constant voltage of 1.8 V for 30 minutes, discharging at a constant current, and calculating from the voltage range of 1.4 V to 0.7 V using the relationship of q = CV. The internal resistance was measured using a commercially available LCR meter at a frequency of 1 kHz. The leakage current value was measured after performing constant voltage charging at 1.8 V for 30 minutes. In addition, as a comparative example, a commercially available activated carbon for electric double layer (YP-50F, manufactured by Kuraray Chemical Co., Ltd.) was prepared and evaluated by the same method.

電気二重層コンデンサの性能と細孔分布との関係を確認するためには、活性炭のグラム当たりではなく、電極単位で評価した方が良いと考えられる。そこで、ミクロ孔およびメソ孔分布のY軸の値:Y、電極中の活性炭の質量割合91/100、電極の密度:E(g/cm)から、以下の(5)式を用いて電極当たりのY軸の値:Yedを算出した。
ed=Y×91/100×E ・・・(5)
In order to confirm the relationship between the performance of the electric double layer capacitor and the pore distribution, it is considered better to evaluate not per gram of activated carbon but per electrode. Then, from the value of the Y-axis of the micropore and mesopore distribution: Y, the mass ratio of activated carbon in the electrode of 91/100, and the density of the electrode: E d (g / cm 3 ), the following equation (5) is used. The value of the Y-axis per electrode: Yed was calculated.
Y ed = Y × 91/100 × E d (5)

2. 結果および考察
表1に、ペレットおよびそれから得られた活性炭の物性を示した。灰分、比表面積、ミクロ孔容積、メソ孔容積は、収率が低くなるに従って高くなった。また、表2に、電気二重層コンデンサ用活性炭の物性を示した。表1との比較から明らかなように、灰分は酸洗浄により低くなった。また、得られた活性炭B1〜B5の平均粒子径は、比較例YP−50Fよりも小さかった。
2. Results and Discussion Table 1 shows the physical properties of the pellets and the activated carbon obtained therefrom. Ash content, specific surface area, micropore volume, and mesopore volume increased with decreasing yield. Table 2 shows the physical properties of the activated carbon for electric double layer capacitors. As is clear from the comparison with Table 1, the ash content was reduced by the acid washing. The average particle diameter of the obtained activated carbons B1 to B5 was smaller than that of Comparative Example YP-50F.

図1〜図4に、本実施例活性炭の収率とかさ密度、比表面積、ミクロ孔容積、メソ孔容積との関係をグラフで示した。これらに図示するように活性炭(A1〜A6)は、収率が低くなるに従って、かさ密度は低く、細孔物性(ミクロ孔容積、メソ孔容積)は高くなる傾向を示した。また、YP−50Fとの比較において、かさ密度は高く、比表面積およびミクロ孔容積は低い結果であった。また、メソ孔容積は、A3のそれが非各区例YP−50Fと同等であった。   FIGS. 1 to 4 graphically show the relationship between the yield of the activated carbon of this example and the bulk density, specific surface area, micropore volume, and mesopore volume. As shown in these figures, activated carbons (A1 to A6) tended to have lower bulk density and higher pore physical properties (micropore volume, mesopore volume) as yield decreased. Moreover, in comparison with YP-50F, the bulk density was high, and the specific surface area and the micropore volume were low. In addition, the mesopore volume of A3 was equivalent to that of the non-each example YP-50F.

図5、図6に、本実施例電気二重層コンデンサ用活性炭のミクロ孔分布、およびメソ孔分布を示した。ミクロ孔分布では、収率が低くなるに従って、すなわちB1、B2、B3、B4、B5となるに従って、そのピークが0.6nmからより大きなサイズの細孔へとシフトすることが分かった。またメソ孔分布も、収率が低くなるに従って、すなわちB1、B2、B3、B4、B5となるに従って、より大きなサイズの細孔の容量が全体的に高くなる傾向が伺え、測定した最大直径のメソ孔では、B5(収率10.8%)が最も高い容量を示した。   5 and 6 show the micropore distribution and the mesopore distribution of the activated carbon for an electric double layer capacitor of this example. In the micropore distribution, it was found that the peak shifted from 0.6 nm to larger pores as the yield became lower, that is, as B1, B2, B3, B4, and B5. Also, as the mesopore distribution decreases, that is, as B1, B2, B3, B4, and B5, the capacity of pores of larger sizes tends to increase as a whole. In the mesopores, B5 (10.8% yield) showed the highest capacity.

表3に、電気二重層コンデンサの静電容量および内部抵抗を示した。試験の結果、静電容量は、B3(収率15.3%)、B4(収率12.6%)において、比較例YP−50Fと同等以上の値を示した。B1(収率23.3%)では静電容量は低かった。   Table 3 shows the capacitance and the internal resistance of the electric double layer capacitor. As a result of the test, in B3 (15.3% yield) and B4 (12.6% yield), the capacitance showed a value equal to or higher than that of Comparative Example YP-50F. In B1 (yield 23.3%), the capacitance was low.

図7に、電気二重層コンデンサの試験時間と静電容量の関係を、また図8に、電気二重層コンデンサの試験時間と内部抵抗との関係を示した。これらに示すように、B3(収率15.3%)が、比較例YP−50Fの静電容量および内部抵抗と同様の挙動を示した。   FIG. 7 shows the relationship between the test time and the capacitance of the electric double layer capacitor, and FIG. 8 shows the relationship between the test time and the internal resistance of the electric double layer capacitor. As shown in these, B3 (yield 15.3%) showed the same behavior as the capacitance and internal resistance of Comparative Example YP-50F.

図9に、各活性炭B1〜B5を用いたそれぞれの電極当たりのミクロ孔分布を、また図10に、図9の0.5〜0.9nmの電極当たりのミクロ孔分布を拡大して示した。前掲表3で静電容量の高かったB3(収率15.3%)、B4(収率12.6%)に注目すると、ミクロ孔分布の中でも特に、0.65〜0.70nm付近のミクロ孔において、高い電極密度を示し、静電容量が高いことが分かった。   FIG. 9 shows the micropore distribution per electrode using each of the activated carbons B1 to B5, and FIG. 10 shows the micropore distribution per electrode of 0.5 to 0.9 nm in FIG. 9 in an enlarged manner. . Focusing on B3 (yield 15.3%) and B4 (12.6% yield), which have high capacitances in Table 3 above, among the micropore distributions, particularly, the micropores in the vicinity of 0.65 to 0.70 nm. It was found that the holes showed high electrode density and high capacitance.

図11に、各活性炭B1〜B5を用いた電極当たりのメソ孔分布を、また図12に、図11中の1〜10nmの電極当たりのメソ孔分布を拡大して示した。ここでも、ミクロ孔分布での評価と同様にB3(収率15.3%)、B4(収率12.6%)に注目したが、ミクロ孔におけるような電極密度・静電容量と細孔サイズとの特徴的な関係を見出すことはできなかった。   FIG. 11 shows the mesopore distribution per electrode using each activated carbon B1 to B5, and FIG. 12 shows the mesopore distribution per electrode of 1 to 10 nm in FIG. 11 in an enlarged manner. Here, as in the evaluation of the micropore distribution, attention was paid to B3 (yield 15.3%) and B4 (yield 12.6%). No characteristic relationship with size could be found.

<実施例2>
1. 実験方法
1.1 コンデンサ用活性炭の調製
1.1.1 活性炭の調製
原料として、ペレット状活性炭(クラレケミカル社製、3GG、C1)を用いた。賦活処理は、活性炭製造実験機(MET社製)を用いて、4200gをキルン容器に投入し、窒素ガス100L/min、水蒸気12mL/minを流通させながら、最高到達温度850℃の条件で行った。C1からの目標収率は賦活時間を調整することで、90%、85%、75%、65%(以下:C2、C3、C4、C5)とした。
<Example 2>
1. Experimental Method 1.1 Preparation of Activated Carbon for Capacitor 1.1.1 Preparation of Activated Carbon Pellet-based activated carbon (3GG, C1 manufactured by Kuraray Chemical Co., Ltd.) was used as a raw material. The activation treatment was carried out using an activated carbon production experimental machine (manufactured by MET) at a maximum temperature of 850 ° C. while introducing 4200 g into a kiln vessel and flowing nitrogen gas 100 L / min and steam 12 mL / min. . The target yield from C1 was adjusted to 90%, 85%, 75%, and 65% (hereinafter, C2, C3, C4, and C5) by adjusting the activation time.

1.1.3 活性炭の洗浄方法
実施例1に述べた内容と同様の方法で洗浄した。
1.2 基本物性の評価
実施例1に述べた内容と同様の方法で基本物性を評価した。
1.3 細孔構造の評価
実施例1に述べた内容と同様の方法で細孔構造を評価した。
1.4 コンデンサの作製および評価
実施例1に述べた内容と同様の方法でコンデンサの作製および評価した。
1.1.3 Activated carbon washing method The activated carbon was washed in the same manner as described in Example 1.
1.2 Evaluation of Basic Physical Properties Basic physical properties were evaluated in the same manner as described in Example 1.
1.3 Evaluation of pore structure The pore structure was evaluated in the same manner as described in Example 1.
1.4 Preparation and Evaluation of Capacitor A capacitor was prepared and evaluated in the same manner as described in Example 1.

2. 結果および考察
表4に、活性炭C1〜C5を用いた電気二重層コンデンサの静電容量、および内部抵抗を示した。本試験の結果、表に示すように、静電容量はC1、C2(目標収率90%)、およびC3(目標収率85%)の各活性炭を用いたコンデンサにおいて、比較例YP−50Fと同等の値を示した。
2. Results and Discussion Table 4 shows the capacitance and the internal resistance of the electric double layer capacitor using the activated carbons C1 to C5. As a result of this test, as shown in the table, the capacitances of the capacitors using activated carbon of C1, C2 (target yield 90%), and C3 (target yield 85%) were compared with those of Comparative Example YP-50F. Equivalent values were shown.

図13に、電極当たりのミクロ孔分布を、また図14に、図13中の0.5〜0.9nmの電極当たりのミクロ孔分布を拡大して示した。これらに示すように、静電容量の高かったC1、C2(目標収率90%)、およびC3(目標収率85%)の各活性炭に注目すると、実施例1のリンゴ剪定枝由来活性炭と同様に、0.65〜0.70nm付近のミクロ孔において電極密度が高いことが分かった。これより、活性炭原料の如何に関わらず、当該範囲のミクロ孔がコンデンサの容量を高めていることが明らかとなった。   FIG. 13 is an enlarged view of the distribution of micropores per electrode, and FIG. 14 is an enlarged view of the distribution of micropores per electrode of 0.5 to 0.9 nm in FIG. As shown in these figures, focusing on the activated carbons C1, C2 (target yield: 90%) and C3 (target yield: 85%) having high capacitance, the same as the activated carbon derived from apple pruned branches in Example 1 In addition, it was found that the electrode density was high in the micropores around 0.65 to 0.70 nm. From this, it became clear that the micropores in the range increased the capacity of the capacitor regardless of the activated carbon raw material.

図15に、電極当たりのメソ孔分布を、また図16に、図15中の1〜10nmの電極当たりのメソ孔分布を示した。ここでも、ミクロ孔分布での評価と同様にC1、C2(目標収率90%)、およびC3(目標収率85%)の各活性炭に注目したが、ミクロ孔におけるような電極密度・静電容量と細孔サイズとの特徴的な関係を見出すことはできなかった。   FIG. 15 shows the mesopore distribution per electrode, and FIG. 16 shows the mesopore distribution per electrode of 1 to 10 nm in FIG. Again, as in the evaluation of the micropore distribution, attention was paid to each activated carbon of C1, C2 (target yield: 90%), and C3 (target yield: 85%). No characteristic relationship between volume and pore size could be found.

<特定ミクロ孔の量比>
以上の試験から、0.65〜0.70nm付近のミクロ孔を、全ミクロ孔中どの程度の量形成できれば、電気二重層コンデンサに適した活性炭であるといえるかを、検討した。
実施例1に係る前掲表3において、電気二重層コンデンサの静電容量は、YP−50F、B3、B4が高い値を示した。図10のB1〜B5およびYP−50FのY軸の値は、高い順に、
直径0.6nmにおいて、B1>B2>B3>YP−50F>B4>B5
直径0.7nmにおいて、YP−50F>B4>B3>B5>B2>B1
直径0.8nmにおいて、YP−50F>B4>B5>B3>B2>B1
となった。
<Quantity ratio of specific micropore>
From the above test, it was examined how much micropores in the vicinity of 0.65 to 0.70 nm can be formed in all the micropores to determine that the activated carbon is suitable for an electric double layer capacitor.
In Table 3 shown in Example 1 above, the electrostatic capacitance of the electric double layer capacitor showed high values in YP-50F, B3, and B4. The values on the Y axis of B1 to B5 and YP-50F in FIG.
At a diameter of 0.6 nm, B1>B2>B3>YP-50F>B4> B5
At a diameter of 0.7 nm, YP-50F>B4>B3>B5>B2> B1
At a diameter of 0.8 nm, YP-50F>B4>B5>B3>B2> B1
It became.

一方、実施例2に係る表4において、静電容量はYP−50F、C1、C2、C3が高い値を示した。図14のC1〜C5およびYP−50FのY軸の値は高い順に、
直径0.6nmにおいて、C1>C2>C3>YP−50F>C4>C5
直径0.7nmにおいて、YP−50F>C1>C2>C3>C4>C5
直径0.8nmにおいて、YP−50F>C5>C4>C3>C1>C2
となった。
On the other hand, in Table 4 according to Example 2, the capacitances of YP-50F, C1, C2, and C3 showed high values. The values of the Y axis of C1 to C5 and YP-50F in FIG.
At a diameter of 0.6 nm, C1>C2>C3>YP-50F>C4> C5
At a diameter of 0.7 nm, YP-50F>C1>C2>C3>C4> C5
At a diameter of 0.8 nm, YP-50F>C5>C4>C3>C1> C2
It became.

表3および表4における電気二重層コンデンサの静電容量の順と、図10、図14の直径0.7nmのY軸の値の順は一致しているため、下限としては、少なくともB3、C3の値以上である0.64nm以上のミクロ孔を所定量形成できれば、電気二重層コンデンサに適した活性炭となる可能性を有すると考えられる(なお、本願においてミクロ孔の孔径範囲の下限を0.65nmとしているのは、実際の試験において確認済みの値を用いたものである)。   Since the order of the capacitance of the electric double-layer capacitor in Tables 3 and 4 and the order of the values of the Y-axis having a diameter of 0.7 nm in FIGS. 10 and 14 match, the lower limit is at least B3 and C3. It is considered that if a predetermined amount of micropores of 0.64 nm or more, which is equal to or more than the above value, can be formed, activated carbon suitable for an electric double layer capacitor can be obtained. The value of 65 nm is a value confirmed in an actual test).

また、孔径0.65nm以上0.70nm以下のミクロ孔は、全ミクロ孔の24.9%以上の量比で含まれていれば、本発明が目的とする電気二重層コンデンサ用活性炭として十分な特性を得ることができる。ここで、量比を24.9%以上とする根拠は、次の通りである。   In addition, if the micropores having a pore diameter of 0.65 nm or more and 0.70 nm or less are contained in a quantitative ratio of 24.9% or more of all the micropores, the activated carbon for an electric double layer capacitor as the object of the present invention is sufficient. Properties can be obtained. Here, the basis for setting the quantity ratio to 24.9% or more is as follows.

上記の量比として、前掲図9および図13の全ミクロ孔に占める0.7nmのミクロ孔の百分率((0.7nmのY値)/(全ミクロ孔のY値の合計)×100)を計算した。この値が高い方が、コンデンサ容量が高いと言える。コンデンサ容量の高かったB3、B4、C1、C2、C3、YP−50Fの各百分率を算出、確認したところ、最もコンデンサ容量が低いB4でも24.9%という量比であった。すなわち、この値以上を有している限り、本発明が課題とする電気二重層コンデンサ用活性炭として十分に高い性能を有する電気二重層コンデンサが得られる、と結論した。   As the above-mentioned quantitative ratio, the percentage of 0.7 nm micropores in all the micropores shown in FIGS. 9 and 13 described above ((0.7 nm Y value) / (sum of all micropore Y values) × 100) is used. Calculated. It can be said that the higher this value is, the higher the capacitor capacity is. The percentages of B3, B4, C1, C2, C3, and YP-50F, each having a high capacitor capacity, were calculated and confirmed. As a result, the quantity ratio of B4 having the lowest capacitor capacity was 24.9%. That is, it was concluded that an electric double layer capacitor having sufficiently high performance as an activated carbon for an electric double layer capacitor, which is a subject of the present invention, can be obtained as long as it has this value or more.

本発明の電気二重層コンデンサ用活性炭、電気二重層コンデンサ、ならびにそれらの製造方法、および電気二重層コンデンサ用電極によれば、精度の高い活性炭を製造できることにより、電気二重層コンデンサ用として適した特性を有する活性炭および電気二重層コンデンサ用電極を提供でき、電気二重層コンデンサを提供することができる。また、廃棄物であるリンゴ剪定枝を有効活用して、かかる有用な活性炭および電気二重層コンデンサ用電極等を提供することができる。したがって、コンデンサ製造・利用分野、農業分野、および関連する全分野において、産業上利用性が高い発明である。
According to the activated carbon for an electric double layer capacitor, the electric double layer capacitor, the method for producing the same, and the electrode for an electric double layer capacitor of the present invention, it is possible to produce activated carbon with high accuracy, so that the characteristics suitable for an electric double layer capacitor can be obtained. Activated carbon and an electrode for an electric double layer capacitor can be provided, and an electric double layer capacitor can be provided. In addition, the useful activated carbon, electrodes for electric double layer capacitors, and the like can be provided by effectively utilizing apple pruned branches as waste. Therefore, the invention is industrially highly applicable in the fields of capacitor production / utilization, agriculture, and all related fields.

Claims (12)

孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれていることを特徴とする、電気二重層コンデンサ用活性炭。 Activated carbon for an electric double layer capacitor, characterized in that micropores having a pore diameter of 0.65 nm or more and 0.70 nm or less are contained at a ratio of 24.9% or more of all micropores. 原料が樹木枝であることを特徴とする、請求項1に記載の電気二重層コンデンサ用活性炭。 The activated carbon for an electric double layer capacitor according to claim 1, wherein the raw material is a tree branch. 原料がリンゴ剪定枝であることを特徴とする、請求項1、または2に記載の電気二重層コンデンサ用活性炭。 The activated carbon for an electric double layer capacitor according to claim 1 or 2, wherein the raw material is apple pruned branches. 樹木枝またはリンゴ剪定枝を原料としたペレットを出発原料としてミクロ孔分布が調整されていることを特徴とする、請求項1ないし3のいずれかに記載の電気二重層コンデンサ用活性炭。 The activated carbon for an electric double layer capacitor according to any one of claims 1 to 3, wherein a micropore distribution is adjusted using a pellet made of a tree branch or an apple pruned tree as a starting material. 孔径0.65nm以上0.70nm以下のミクロ孔が全ミクロ孔の24.9%以上の量比で含まれるように調整される過程を備えることを特徴とする、電気二重層コンデンサ用活性炭製造方法。 A method for producing activated carbon for an electric double layer capacitor, comprising a step of adjusting so that micropores having a pore diameter of 0.65 nm or more and 0.70 nm or less are contained in a quantity ratio of 24.9% or more of all micropores. . 樹木枝を原料としたペレットを出発原料とすることを特徴とする、請求項5に記載の電気二重層コンデンサ用活性炭製造方法。 The method for producing activated carbon for an electric double layer capacitor according to claim 5, wherein a pellet made from a tree branch is used as a starting material. リンゴ剪定枝を原料としたペレットを出発原料とすることを特徴とする、請求項5に記載の電気二重層コンデンサ用活性炭製造方法。 The method for producing activated carbon for an electric double layer capacitor according to claim 5, wherein a pellet made from apple pruned branches is used as a starting material. 原料活性炭の賦活処理過程を、供する炭化物(賦活処理前)の粒子サイズ、処理量(投入量)、窒素ガス流通量、水蒸気流通量、設定最高到達温度、賦活処理時間の各処理条件のうち、少なくともいずれか一つの条件を特定させた賦活処理過程とすることを特徴とする、請求項5ないし7のいずれかに記載の電気二重層コンデンサ用活性炭製造方法。 In the activation process of the raw material activated carbon, the particle size of the carbide to be provided (before the activation process), the throughput (input amount), the nitrogen gas flow rate, the steam flow rate, the set maximum attainment temperature, and the activation process time The method for producing activated carbon for an electric double layer capacitor according to any one of claims 5 to 7, wherein the activation process is performed by specifying at least one condition. 賦活処理過程における他の条件を固定した上で最適なミクロ孔分布が得られる賦活処理時間をあらかじめ試験しておき、それによって特定される賦活処理時間を条件として用いて製造することを特徴とする、請求項5ないし8のいずれかに記載の電気二重層コンデンサ用活性炭製造方法。 It is characterized in that the activation process time at which the optimum micropore distribution is obtained after fixing other conditions in the activation process is tested in advance, and the activation process time specified thereby is used as a condition for production. The method for producing activated carbon for an electric double layer capacitor according to any one of claims 5 to 8. 請求項1ないし4のいずれかに記載の電気二重層コンデンサ用活性炭、または請求項5ないし9のいずれかに記載の電気二重層コンデンサ用活性炭製造方法により製造される電気二重層コンデンサ用活性炭を用いていることを特徴とする、電気二重層コンデンサ用電極。 The activated carbon for an electric double layer capacitor according to any one of claims 1 to 4, or the activated carbon for an electric double layer capacitor manufactured by the method for producing an activated carbon for an electric double layer capacitor according to any one of claims 5 to 9 is used. An electrode for an electric double layer capacitor. 請求項1ないし4のいずれかに記載の電気二重層コンデンサ用活性炭、または請求項5ないし9のいずれかに記載の電気二重層コンデンサ用活性炭製造方法により製造される電気二重層コンデンサ用活性炭を用いていることを特徴とする、電気二重層コンデンサ。 The activated carbon for an electric double layer capacitor according to any one of claims 1 to 4, or the activated carbon for an electric double layer capacitor manufactured by the method for producing an activated carbon for an electric double layer capacitor according to any one of claims 5 to 9 is used. An electric double-layer capacitor. 請求項1ないし4のいずれかに記載の電気二重層コンデンサ用活性炭、または請求項5ないし9のいずれかに記載の電気二重層コンデンサ用活性炭製造方法を用いて製造することを特徴とする、電気二重層コンデンサ製造方法。
An activated carbon for electric double layer capacitors according to any one of claims 1 to 4, or an activated carbon for electric double layer capacitors according to any one of claims 5 to 9. Double layer capacitor manufacturing method.
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