著者

Sota OKABE Satoshi UCHIDA Yukiko MATSUI Masaki YAMAGATA Masashi ISHIKAWA

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.85, no.10, pp.671-674, 2017-10-05 (Released:2017-10-05)

参考文献数

13

被引用文献数

6

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We prepared activated carbon (AC) and sulfur (S) composite cathodes. The present AC has developed micropores and a large pore volume. The composite could successfully include a large amount of S and exhibited stable cycle performance in a glyme-based electrolyte. An oxidation treatment of the AC with a concentrated nitric acid solution at 120°C was found to improve S utilization in charge-discharge cycling. A cathode with the oxidized AC including S showed stable cycle performance with a high capacity in not only the glyme-based electrolyte but also a carbonate-based electrolyte.

著者

Shinya USUKI Satoshi UCHIDA Yukiko MATSUI Masaki YAMAGATA Hidenori HINAGO Masashi ISHIKAWA

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.85, no.10, pp.650-655, 2017-10-05 (Released:2017-10-05)

参考文献数

22

被引用文献数

10

---

Micropore-rich activated carbon with high surface area and pore volume was prepared by alkali activation of azulmic carbon (AZC) precursor as nitrogen-doped carbon; AZC was a carbonized product from azulmic acid. We successfully loaded a large amount of sulfur (S) into micropores of the activated AZC. Our two kinds of activated AZC (BET surface area: 1,747 and 2,319 m2 g−1) can include S up to 55 and 62 wt%, respectively. The former activated AZC including S can be charged and discharged with lithium (Li) ion transfer stably and reversibly in glyme-based and carbonate-based electrolytes. The latter activated AZC can be charged and discharged in a glyme-based electrolyte. These different characteristics are due to a difference in fine pore structure between them. Our microporous activated AZC with high S loading is promising material as positive S electrode for rechargeable Li-S batteries.

著者

篠田 渉 岡崎 進

出版者

電気化学会

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.68, no.2, pp.129-133, 2000-02-05

参考文献数

26

被引用文献数

1

著者

内田 悟史 石川 正司

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.85, no.8, pp.490-494, 2017-08-05 (Released:2017-08-05)

参考文献数

13

著者

松永 真理子

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.12, pp.1114-1115, 2014

著者

米澤 正智 雨宮 千夏

出版者

The Electrochemical Society of Japan

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.74, no.3, pp.240-244, 2006-03-05

参考文献数

32

著者

中山 邦彦 渋谷 光夫 石川 正司

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.76, no.12, pp.886-890, 2008-12-05 (Released:2012-03-22)

参考文献数

12

---

Alkaline polymer gel electrolytes mainly with modified polyvinyl alcohol (PVA) have been prepared for an electric double layer capacitor (EDLC). Their electrochemical characteristics were evaluated by impedance spectroscopy and constant-current charge/discharge measurement. The prepared gel electrolyte film with KOH exhibits excellent flexibility and an ionic conductivity of about 7×10−2 S cm−1 at 298 K. The gel electrolyte EDLC shows comparable discharge capacitance to that for EDLC containing a conventional aqueous electrolyte. These results suggest that the gel electrolyte based on the modified PVA is promising material for use in EDLC.

著者

Kohei IKEDA Shoshi TERADA Toshihiko MANDAI Kazuhide UENO Kaoru DOKKO Masayoshi WATANABE

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.10, pp.914-917, 2015-10-05 (Released:2015-10-05)

参考文献数

22

被引用文献数

1 15

---

The electrochemical properties of a mechanochemically synthesized Li22Sn5 electrode in a solvate ionic liquid-based electrolyte were investigated. The electrolyte was composed of lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]), tetraglyme (G4), and a hydrofluoroether solvent (HFE) in a molar ratio of 1:1:6.2, in which Li+ and G4 formed a 1:1 complex cation of [Li(G4)]+. The Li22Sn5 electrode exhibited an initial discharge capacity of 500 mA h g−1 in this electrolyte; however, the capacity decreased with increased numbers of charge-discharge cycles. This was attributed to the Li-Sn alloy’s volume change in the electrode during the electrochemical reaction. To examine the behavior of the electrode material in a lithium-sulfur battery, a full cell consisting of a Li22Sn5 anode, S cathode, and [Li(G4)][TFSA]/HFE electrolyte was fabricated. The cell was discharged and charged stably without severe side reactions. The dissolution of lithium polysulfides, reaction intermediates with the sulfur cathode, was effectively suppressed in the electrolyte, leading to efficient charge-discharge cycling of the Li22Sn5-S cell.

著者

Luo PENG Xiao-Ting ZHANG Satoshi KAWAICHI De-Ti XIE Zhen-Lun LI

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.8, pp.600-604, 2015-08-05 (Released:2015-08-05)

参考文献数

28

被引用文献数

2

---

In bioelectrochemical systems where the oxidative current is mediated by microorganisms, it remains unexplored as to whether low-potential substrates (e.g. formate) enable the anode to work at lower potentials. Due to implications to relevant engineering and natural systems, this study evaluated such possibility and underlying causes. The investigation compared voltammograms of the model exoelectrogen (to exclude the interfering factors in undefined cultures) Geobacter sulfurreducens grown with acetate and formate. G. sulfurreducens had an EM (half-saturation potential) of −0.138 ± 0.004 V vs. SHE when consuming acetate; an EM of −0.160 ± 0.002 V when utilizing formate. Such variation usually requires alternation in electrode reductase expressed by bacteria, according to the existing Nernst-Monod model with a single species of electron conduit. For both acetate- and formate-grown biofilm, non-catalytic voltammetries found multiple redox couples with distinct formal potentials. No clear evidence could support a hypothesis that the bacteria synthesized any different electron conduits when the substrate was changed. Significant changes in the relative abundance of high-potential and low-potential electrocatalytically active conduits were not observed as well. However, low-potential conduits showed elevated electrocatalytic activities in the formate-grown biofilm, which might induce the shift in apparent EM.

著者

Xiao DENG Ryuhei NAKAMURA Kazuhito HASHIMOTO Akihiro OKAMOTO

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.7, pp.529-531, 2015-07-05 (Released:2015-07-05)

参考文献数

12

被引用文献数

3 40

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We report that an intensely iron-corroding microbe, Desulfovibrio ferrophilus strain IS5, is capable of extracting electrons from an indium tin-doped oxide electrode without consuming electrochemically generated hydrogen as an electron carrier. When sulfate was presented as a metabolic electron acceptor, significant cathodic current production was observed at an onset potential of −200 mV vs. SHE, which was approximately 750 mV more positive than the onset for hydrogen evolution in our experimental condition. This finding indicates that hydrogen is not required for the cathodic reaction of IS5, suggesting that IS5 accelerates anaerobic iron corrosion through direct electron uptake.

著者

Hiroto FUNABASHI Kazuki MURATA Seiya TSUJIMURA

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.5, pp.372-375, 2015-05-05 (Released:2015-05-05)

参考文献数

26

被引用文献数

8 40

---

MgO-templated porous carbon (MgOC) was developed for D-fructose dehydrogenase (FDH) electrodes. MgOCs with an average pore diameter ranging from 10 to 100 nm were used in this study. FDH adsorbed on a MgOC electrode exhibited significant catalytic currents for D-fructose-oxidation without a redox mediator. When the pore size of MgOC was much larger than the size of FDH, a sufficient amount of FDH was adsorbed in the mesopore on and even inside the MgOC structure. In contrast, when the pore size of MgOC was comparable to the size of FDH, the catalytic current depended only on the amount of enzyme adsorbed in mesopores formed at the surface of the carbon particles; however, an enhanced thermal stability of FDH was observed. Thus, FDH was stabilized through encaging in carbon mesopores with a size comparable to that of the enzyme.

著者

Maiko KAWAKUBO Masaki MATSUI Sumihisa ISHIKAWA Atsushi HIRANO Osamu YAMAMOTO Yasuo TAKEDA Nobuyuki IMANISHI

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.8, pp.642-646, 2014-08-05 (Released:2014-08-05)

参考文献数

14

被引用文献数

2

---

Degradation processes of carbon negative electrodes for all-solid lithium polymer batteries were investigated using X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and Scanning Electron Microscope (SEM). The cycling performances of the electrodes are significantly affected by the mixing speed of the electrode slurry. The cross-sectional SEM images of the electrodes containing vapor-grown carbon fiber (VGCF) show that more voids remained in the electrodes, if the slurry was mixed at high speed. The voids in the composite electrode expand and increase during the cycling test of the cell resulting in the capacity fading. On the other hand, the electrodes containing carbon nanotubes (CNT) show an opposite trend, because the high mixing speed improves the dispersibility of the CNT resulting in the formation of the less voids in the electrode. The electrode containing both VGCF and CNT prepared at high mixing speed shows the best cycleability among all the electrodes. In spite of some voids initially form in the electrode, the CNT seems to have prevented further increase and expansion of the voids.

著者

藤ヶ谷 剛彦 田中 泰彦 中嶋 直敏

出版者

The Electrochemical Society of Japan

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.78, no.1, pp.2-15, 2010-01-05

被引用文献数

4

---

One of the key issues in the utilization of carbon nanotubes (CNTs) for basic researches as well as their applications is to develop a methodology to solubilize/disperse them in solvents. In this review articles, we first summarize individual solubilization of single-walled carbon nanotubes (SWNTs) in solvents using surfactants, polycylcic aromatic molecules, DNA and condensed polymers. We then describe a novel method determining the electronic states of individually dissolved SWNTs having an own chirality index based on the analysis of Nernst equation. We also introduce our recent approach toward the fabrication of a novel catalyst for fuel cell that works at a nonhumid atmosphere using solubilized CNTs as material.

著者

Masaki YAMAGATA Masaya HIRAYAMA Satoshi NISHISHITA Daisuke HORIKAWA Masashi ISHIKAWA

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.10, pp.857-862, 2013-10-05 (Released:2013-10-05)

参考文献数

34

被引用文献数

3 7

---

The charge-discharge behavior of electric double-layer capacitors (EDLCs) composed of several ionic liquids and their lithium solutions were evaluated. The model EDLC cell with a Li+-containing ionic liquid electrolyte, LiTFSI/EMImFSI (LiTFSI = lithium bis(trifluoromethylsulfonyl)imide, EMImFSI = 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide), exhibited a higher discharge capacitance than the cell containing EMImFSI, whereas the discharge capacitance of the cell with LiTFSI/EMImTFSI was lower than that of the cell containing EMImTFSI. In addition, the cells composed of EMImBF4-based electrolytes displayed similar charge-discharge characteristics irrespective of the presence of the corresponding lithium salts. The distinctive results for the EDLCs with lithium-containing ionic liquid electrolytes are also discussed based on the application of the electrochemical impedance technique to model carbon electrodes in ionic liquids. According to the obtained differential capacitance of the model glassy carbon electrode in each ionic liquid electrolyte, the electric double-layer (compact layer) structure at the electrode/electrolyte interface depends on the component anion species of the ionic liquid and the co-existence of the anion and Li+.

著者

Kazunari SOEDA Masaki YAMAGATA Shigeaki YAMAZAKI Masashi ISHIKAWA

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.10, pp.867-872, 2013-10-05 (Released:2013-10-05)

参考文献数

21

被引用文献数

13

---

Chitosan-based gel electrolytes with ionic liquids (Chi/IL) were prepared and investigated for use in electric double-layer capacitors (EDLCs). The voltage drop for the test cell with Chi/EMImBF4 (EMImBF4 = 1-ethyl-3-methylimidazolium tetrafluoroborate) or Chi/DEMEBF4 (DEMEBF4 = N,N-diethyl-N-methyl-N-2-methoxyethylammonium tetrafluoroborate) and activated carbon fiber cloth electrodes (ACFCs) was smaller than that with the corresponding ionic liquid electrolyte. To clarify the effect of the presence of Chi in contact with the carbon electrode, we also prepared the Chi-containing ACFC electrode (Chi+ACFC) and evaluated its charge-discharge characteristics in EMImBF4. The results proved that the presence of Chi on the active materials reduces the internal resistances of the cell and plays an important role in the improvement of the EDLC performance. In addition, the high-voltage operation of the test cells with Chi-based gel electrolytes was investigated. These results suggest that the Chi is suitable for use in practical high-performance and safe EDLCs.