Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：SAE International  

<div class="section abstract"><div class="htmlview paragraph">Electric double-layer capacitors (EDLCs) store charge by adsorbing ions at the electrode–electrolyte interface, offering fast charge–discharge rates, high power density, minimal heat generation, and long cycle life. These characteristics make EDLCs ideal for memory backup in electronic devices and power assistance in electric and hybrid vehicles, where rapid energy response and high-power delivery are critical. However, their energy density remains lower than that of batteries, requiring improvements in capacitance and operating voltage. Activated carbon with high surface area is commonly used as the electrode material, but its microporous structure limits ion transport at high rates, reducing power performance. This limitation is especially critical in automotive motor drive systems. Recent research has shifted toward mesoporous carbon materials, which improve ion diffusion and accessibility. In this study, resorcinol–formaldehyde carbon cryogels (RFCCs) with controlled mesoporous architectures were synthesized and applied as EDLC electrode materials, in combination with organic electrolytes that provide a wider electrochemical window. A CO<sub>2</sub>-activated RFCC (RFCC-CO<sub>2</sub>) demonstrated the most balanced electrochemical performance, combining high surface area and interconnected mesoporous networks. Characterization using scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) surface area analysis confirmed the hierarchical porous structure. Electrochemical evaluations through cyclic voltammetry (CV) and constant current charge–discharge measurements demonstrated that RFCC-CO<sub>2</sub> achieved high specific capacitance and excellent rate capability. These results point to the importance of mesopore engineering in addressing ion transport limitations in conventional carbon materials and highlight RFCC-CO<sub>2</sub> as a promising electrode candidate for EDLCs in regenerative braking and other fast-response electric mobility applications.</div></div>

DOI： 10.4271/2025-01-5064

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Authorship：Lead author   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10853-025-11471-8

Scopus

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：THE CARBON SOCIETY OF JAPAN  

Hard water is water that contains cations, especially Ca²⁺ and Mg²⁺ that can participate in reactions that leave insoluble mineral deposits. These deposits make hard water unsuitable for many uses, and so a variety of methods have been developed to remove these ions. We have attempted to remove them by using the principle of electric double layer adsorption. This system has advantages such as electrode reproducibility and reusability. This report investigates the efficient removal of these ions by electric double layer adsorption and the effectiveness of mesoporous carbon electrodes.

DOI： 10.7209/tanso.2021.65

DOI： 10.1016/j.carbon.2021.03.036

CiNii Books

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I031398523

Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Surface Finishing Society of Japan  

Mesoporous carbon nanofilament（CNF）can maintain capacitance in a higher sweep rate area than microporous carbon（activated carbon）. Therefore, synthesized mesoporous CNF is applicable as an electrode material in electric double layer capacitors. For this study, the porous structure and surface area of mesoporous CNF, synthesized by decomposition of C₂H₄ using metallic complex at a mild temperature, were controlled using a catalyst. Results show that the capacitance of the mesoporous CNF per unit of specific surface area is higher than that of activated carbon, demonstrating that it is a suitable electrode material that can improve the rate characteristics of electric double layer capacitors.

DOI： 10.4139/sfj.68.635

CiNii Books

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I028663256

Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

DOI： 10.1252/kakoronbunshu.43.45

DOI： 10.4139/sfj.68.635_references_DOI_Rq7V0aYJFFLyDzqZxUsgL2fxESU

Scopus

CiNii Books

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Authorship：Corresponding author   Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

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Other Link： https://global.yamaha-motor.com/jp/design_technology/technical/

Authorship：Lead author   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：SAE International  

<div class="section abstract"><div class="htmlview paragraph">Electric double-layer capacitors (EDLCs) store charge by adsorbing ions at the electrode-electrolyte interface, offering fast charge/discharge rates, high power density, minimal heat generation, and long cycle life. These characteristics make EDLCs ideal for memory backup in electronic devices and power assistance in electric and hybrid vehicles. However, their energy density is lower than that of batteries, necessitating improvements in electrical capacity and potential. Traditionally, activated carbon with a high specific surface area has been used, but recent research focuses on mesoporous carbon materials for better ion diffusion. This study uses resorcinol-formaldehyde-carbon cryogel (RFCC) with mesopores and organic electrolytes with a wider electrochemical window. Various RFCCs with different pore sizes were synthesized and evaluated. Comprehensive investigations into the pore structures and surface properties of both synthesized carbon gels and commercial mesoporous materials were conducted. EDLCs with organic electrolytes were fabricated, and their electrochemical performance was analyzed. Findings indicate that mesoporous carbon gels significantly enhance capacity in high-rate charge-discharge cycles due to improved ion diffusion, highlighting their potential in optimizing EDLC performance.</div></div>

DOI： 10.4271/2024-32-0026

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J-GLOBAL

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J-GLOBAL

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Authorship：Lead author   Publisher：The Electrochemical Society  

Electric double-layer capacitor (EDLC) has been required high capacitance and high-rate performance. The capacitance of EDLC comes from the electrostatic charge accumulation at the interface between electrode and electrolyte. So the capacitance is highly dependent on the surface area of elecrode material. For this reason, microporous activated carbon had been used for many years as EDLC electrode materials. However, recent research use organic electrolyte to enhance the energy density of EDLC. In this case, microporous electrode materials are not good at ion transport and reduce rate perfermance because of the large ion diameter of organic electrolyte. Therefore, an optimal electrode material must provide an appropriate pore size for ion transport. Recently, mesoporous materials have been reported to be more effective in increasing capacitance at high charge/discharge rates.

Based on the recent reports, we focused on the study of novel mesoporous materials. We prepared several kinds of mesoporous materials carbon gel RFCX (resorcinol formaldehyde carbon xerogel) with different pore size distribution. RFCX is a kind of mesoporous carbon material with a 3D interconnected network structure and under the control of the pore structure by varying certain conditions of the sol-gel process. We controled the concentration of catalyst and developed three types of mesoporous materials carbon gel RFCX with a large number of mesopores around 10 nm, 25 nm and 40 nm. For comparison, we used two kinds of commercial activated carbon products M (surface area 900 m²g^-1) and Y (surface area 1500 m²g^-1). Both of them are high-surface-area microporous activated carbon. And we examined each sample’s electrochemical behavior as the electrode for electric double-layer capacitors in organic electrolyte of tetra ethyl ammonium tetra fluoroborate in propylene carbonate (TEABF₄/PC). Ion diameter of electrolyte ion TEA⁺ in solvation is 1.96 nm. And ion diameter of electrolyte ion BF₄ ^- in solvation is 1.71 nm. Diameter was caculated by Car-Parrinello method.

Carbon gel RFCX enhanced the electrolyte ion transport by the large pore diameter (2 ~ 50 nm). RFCXs showed higher surface areal capacitance of 4.0 ~ 6.2 μF cm⁻²than the commercial product M (0.5 ~1.5 μF cm⁻²) in organic electrolyte. Though they are the similar surface area (about 800 m²g^-1 and 900 m²g^-1). Moreover, the RFCXs also showed higher surface areal capacitance than the commercial product Y (2.2 ~ 3.5 μF cm⁻²). Though surface area of RFCX is only a half of Y (1500 m²g^-1). And RFCXs showed high-rate performance of 70% owing to the large mesopore volume. These results indicated that capacitance of EDLC in organic electrolyte indepandent of surface area of electrode material. Thus, we considered that the volume rate of mesopore of electrode material is one of the most important determinant of rate performance.

In summary, EDLC based on the mesoporous carbon RFCX exhibited better electrochemical performance than microporous activated carbon in organic electrolyte. It is considered that RFCX has potential for high performance energy-related applications.

DOI： 10.1149/ma2016-02/8/1081

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Other Link： https://iopscience.iop.org/article/10.1149/MA2016-02/8/1081/pdf

Event date： 2026.9

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2026.9

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2024.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Bangkok, Thailand   Country：Thailand  

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Event date： 2016.10

Language：English   Presentation type：Poster presentation  

Venue：Honolulu, Hawaii, USA.   Country：United States  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

○ 最優秀賞
Ｐ-３
メソ孔性ナノ炭素材料ナノカーボンゲルの作製とそれを電気二重層キャパシタ電極への応用
（関大院・理工）○ 程 再冉，（ 関西大学＆HRC）小田 廣和，中川 清晴*

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