著者

上岡 永佳 渡邉 一哉

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.84, no.2, pp.104-106, 2016-02-05 (Released:2016-02-05)

参考文献数

16

著者

松本 邦男

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.12, pp.821-822, 2017-12-05 (Released:2017-12-05)

著者

Koichi MITSUDO Takahiro OKADA Shuichi SHIMOHARA Hiroki MANDAI Seiji SUGA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.5, pp.362-364, 2013-05-05 (Released:2013-05-05)

参考文献数

14

被引用文献数

1 22

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An electro-reductive halogen-deuterium exchange reaction in CD3CN has been developed. Using 9-fluorenone as a mediator, the electro-reduction of several aryl halides proceeded smoothly to give the deuterated products selectively. A methylation reaction of aryl halides also proceeded under similar conditions.

著者

山内 悠 野村 聡

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.80, no.6, pp.445-448, 2012-06-05 (Released:2012-06-05)

参考文献数

10

著者

Keishi MATSUO Yoshiyuki TAKATSUJI Masahiro KOHNO Toshiaki KAMACHI Hideo NAKADA Tetsuya HARUYAMA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.9, pp.721-724, 2015-09-05 (Released:2015-09-05)

参考文献数

10

被引用文献数

7 12

---

Efficient generation of oxygen radicals and reactive oxygen was successfully performed at the dispersed-phasic interface between vapor-water and oxygen plasma in a reaction chamber having an internal atmosphere with a normal-pressure and temperature. In the space of the reactor chamber (radical vapor reactor [RVR]), the gas phase was strictly controlled in terms of vaporized water (small water mist), temperature, plasma conditions, and UV irradiation. According to spin-trapping electron spin resonance analysis, the RVR efficiently and quantitatively yielded two types of reactive oxygen species (1O2 and OH radical) with the atmosphere of the RVR chamber. This is the report of the efficient, quantitative production of reactive oxygen in an atmosphere. The reactivity of the produced 1O2 and OH radical may be applicable for various chemical processes, such as oxidation and electron absorption.

著者

Mika FUKUNISHI Tatsuo HORIBA Mouad DAHBI Kei KUBOTA Satoshi YASUNO Shinichi KOMABA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.87, no.1, pp.70-77, 2019-01-05 (Released:2019-01-05)

参考文献数

24

被引用文献数

4

---

A nanometer-sized Sn (nano-Sn) powder composite electrode with polyacrylate binder delivers a discharge capacity of 600 mAh g−1 with a good capacity retention for 100 cycles in non-aqueous Na cells, however, a micrometer-sized Sn (micro-Sn) composite electrode exhibits an insufficient cycle performance under the same condition. Although surface analysis of cycled electrodes reveals no apparent difference in solid electrolyte interphase layer formed on the nano- and micro-Sn electrodes, we found that in the case of nano-Sn electrodes the moderately porous composite layers and thin binder coating on Sn particles are responsible for a favorable cycle performance. On the other hand, the dense and less-porous micro-Sn electrode having a relatively thicker coating of binder on micro-Sn particles deteriorates the reversibility of sodium alloying reaction. Therefore, we optimize the electrode preparation process to introduce the suitable porosity and properly thin binder coating in the micro-Sn composite electrodes. The optimization enables the micro-Sn electrode to demonstrate high reversible sodiation capacity of 676–470 mAh g−1 with much improved capacity retention over 100 cycles.

著者

Junji SUZUKI Narumi KUBOTA Yukikazu OMURA Keisuke SUGATA Kento KISA Hiroaki SOFUJI Mayumi HATTORI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.3, pp.116-121, 2018-05-05 (Released:2018-05-05)

参考文献数

20

被引用文献数

1

---

The development of SIB has attracted attention as a substitute for LIB. Low-temperature-fired soft carbon (LFSC) has been the target of study as SIB’s useful negative electrode material. We estimated Na chemical diffusion coefficient Dchem using the same approach and samples of previous report on LIB. The approach was potential step chronoamperometry (PSCA) method, and the samples were mesophase-pitch-based carbon fiber fired at four different low temperatures (600, 700, 800 and 950°C). The PSCA measurements by using a single LFSC fiber electrode were performed in an electrolyte of propylene carbonate (PC) containing 1 M NaClO4 at room temperature in a glove box filled with dried Ar. The largest Dchem value we obtained with four pristine LFSC was about 10−9 cm2/sec. The Dchem values depended not only on firing temperature of LFSC but also on the nature of LFSC’s surface. The effective surface treatment promoted Na insertion/extraction reaction rate on the carbon surface. The largest Na Dchem value we obtained after surface treatment was 10−8 cm2/sec. This Na Dchem value was close to the Li Dchem value (10−7.5 cm2/sec) by previous report, which suggests possibility of SIB’s practical use.

著者

山田 淳夫

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.3, pp.169-174, 2014-03-05 (Released:2014-03-05)

参考文献数

40

著者

Tadayoshi SAKATA Toshihito OHTAKE Masashi AZUMA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.4, pp.158-174, 2018-07-05 (Released:2018-07-05)

参考文献数

27

被引用文献数

2

---

Quantum mechanical theory of electrochemical kinetics based on Fermi’s golden rule was formulated by introducing the concept of electron transfer distance. The expressions for the exchange current density and standard rate constant in electrochemistry were derived in analytical form, as well as exponential current overpotential dependence. The theory corresponds well to the electrode kinetics based on the transition state theory. It was applied to various kinds of electrode reactions to analyze the standard rate constants and the exchange current densities reported in past literature. The evaluated magnitudes of the electron exchange energy were very small, being in the order of 10−3 eV–10−5 eV. A new theory of transfer coefficient was constructed based on Debye-Hückel theory for electrolyte solutions could explain quantitatively the dependence of the transfer coefficient on the ionic strength of electrolyte solutions. It was demonstrated that the transfer coefficient represents electrostatic screening of the electrode potential by ions near the electrode and its magnitude was calculated quantitatively. Electron transfer distance was obtained by analyzing the dependence of the transfer coefficient on the ionic strength of electrolyte solutions. Our theory supported the ordinary electron transfer mechanism due to the overlap of wave functions between the electrode and redox species, denying tunneling mechanism.

著者

安武 幹雄 高津戸 真広 田村 拓也 山田 佳那 神谷 翼 廣瀬 卓司

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.12, pp.768-774, 2017-12-05 (Released:2017-12-05)

参考文献数

32

被引用文献数

1

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Three kinds of liquid crystalline compounds (AQBD1, AQBD2 and AQBT) having an anthraquinone and a bithiophene moieties were synthesized. The mesophases have been characterized by polarized optical microscopy (POM) observation, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. AQBD1 and AQBT were determined to form colomnar phases while AQBD2 showed a smectic phase. The disc units of the columnar phases of AQBD1 and AQBT were expected to contain 2 and 3 molecules, respectively. The electrochemical properties of AQBT, which keeps the liquid crystalline phase at room temperaure, were examined by cyclic voltammetry (CV) and optoelectrochemical measurements. The reversible electrochemical response of AQBT was confirmed in solution. The reversible color change of EC device prepared from liquid crystalline AQBT (LC-AQBT) was also observed at room temperaure and the positive potentials, which is due to the bithiophene unit.

著者

宇田川 憲一

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.4, pp.173, 2017-04-05 (Released:2017-04-05)

著者

Keisuke KIKUCHI Tomohiro YASUE Rie YAMASHITA Satoshi SAKURAGAWA Masao SUDOH Masayuki ITAGAKI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.10, pp.828-832, 2013-10-05 (Released:2013-10-05)

参考文献数

26

被引用文献数

4 14

---

Large amounts of spent coffee grounds (SCGs) are generated all over the world. Since SCGs contain a lot of carbon and inherently has a porous structure, SCGs are considered to be a valuable industrial resource by carbonization. According to our previous research, it was apparent that the specific surface area of SCGs-derived carbon was greatly improved by potassium hydroxide (KOH) activation. In this research, we prepared an electric double layer capacitor (EDLC) using SCGs-derived carbon activated with KOH, and compared them to phenol resin-derived activated carbon (MSP-20, Kansai Coke and Chemicals Co., Ltd.), which is commonly used as a reference material in EDLC research. Electrodes were prepared by mixing 80 wt% activated carbon, 10 wt% carbon black and 10 wt% polytetrafluoroethylene (PTFE) and the electrolyte used was 1 M triethylmethylammonium-tetrafluoroborate (TEMA-BF4)/propylene carbonate (PC). The capacitive performance was evaluated by a constant current charge-discharge cycle measured with various electrical current loads from 5 to 150 mA/cm2. Although the capacitance of SCGs-derived carbon activated with KOH was inferior to that of MSP-20 at low current load density, it had high capacitance in high rate charge-discharge cycles. This suggests that the EDLC consisting of SCGs-derived activated carbon electrodes is superior to MSP-20 in capacitance retention rate when used at a high electric current density.

著者

Yutaro NORIKAWA Kouji YASUDA Toshiyuki NOHIRA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.2, pp.99-103, 2018-04-05 (Released:2018-04-05)

参考文献数

31

被引用文献数

13

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The electrochemical behavior of Ti(III) ions in a eutectic KF–KCl molten salt was investigated using cyclic voltammetry, square wave voltammetry, and chronoamperometry at 923 K. Ti(III) ions were produced by the addition of 0.50 mol% of K2TiF6 and 0.33 mol% of Ti sponge to the melt. The reduction of Ti(III) ions to metallic Ti was observed as a single 3-electron wave around 0.33 V vs. K+/K in the square-wave voltammogram. The electrodeposition was conducted at a Mo electrode by galvanostatic electrolysis at −50 mA cm−2 for 20 min. The deposits were confirmed to be compact and adherent Ti metal films by scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction analysis. The oxidation of Ti(III) to Ti(IV) was observed at 1.82 V vs. K+/K as a reversible electrochemical process. The diffusion coefficient of Ti(III) ions was determined to be 3.9 × 10−5 cm2 s−1.

著者

Fuxing ZHU Kehui QIU Zhaohui SUN

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.11, pp.715-720, 2017-11-05 (Released:2017-11-05)

参考文献数

31

被引用文献数

10

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Titanium was prepared from TiCl4 in molten NaCl-KCl-NaF salt. The product of the reaction of TiCl4 with NaF was identified using X-ray diffraction, and its electrochemical behavior was studied using cyclic voltammetry and square wave voltammetry. The electrochemical deposition of titanium was investigated during the addition of TiCl4 to NaCl-KCl-NaF melts. The results indicate that Na2TiF6 was first obtained through the reaction of NaF with TiCl4 in the NaF-KCl-NaCl melt, and Na2TiF6 was decomposed to Na+ and [TiF6]2− in the melts. [TiF6]2− was then sequentially reduced to [TiF6]3− and Ti at the cathode, accompanied by chlorine gas emission at the anode and fluoride formation at the cathode.

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

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

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

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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.