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Song for Electrochemistry

Academic and technical staff

Professor	Yasuhiro AWAKURA	Dr. Eng.
Associate Professor	Tetsuya UDA	Dr. Eng.
Assistant Professor	Yoshitaro NOSE	Dr. Eng.
Technical Official	Tokuji TANAKA

Dr. Kuniaki MURASE (former assistant professor) has been transferred to Nanoscopic Surface Architecture Laboratory.

Students (2007)

Research Interests

Our laboratory was inaugurated in 1994 during the reorganization of Department of Materials Science and Engineering. The forerunner of our laboratory was the Electrometallurgy Division of Department of Metallurgy, where we were working on hydrometallurgy, e.g. aqueous thermodynamics, electrowinning, leaching and extraction. In addition to some hydrometallurgical processes, our group is currently interested in the study of electrochemical growth of thin film materials.

Currently Active Topics

1.Electrodeposition of semiconductors

2. Composite electrodeposition using nonaqueous and aqueous media

3.Electrodeposition of metals and alloys from novel ionic liquids

4.Electrochemical alloy formation for corrosion-resistant coatings

5. Fuel cell at intermediate temperature since 2005.

Electrodeposition of semiconductors

Some compound semiconductors are promising materials for the next generation of solar cell devices. Thin layered CdTe has been well-investigated, since the band gap (1.45 eV) is suitable for energy conversion from sunlight to electricity, and has already been produced commercially by an electrodeposition technique using acidic baths, the drawback of which is the low solubility of Te(IV) ions. To resolve the problem, we have been developing a novel ammoniacal basic bath containing 10 mol dm^-3 of Te(IV) ions. Studies are presently directed towards (a) understanding the mechanism of photo-assisted electrodeposition of CdTe, (b) investigation of electrical and structural properties of resulting CdTe, and (c) production and characterization of CdS | CdTe solar cell.

-- Selected papers --

• K. Murase, H. Tada, T. Shinagawa, M. Izaki, and Y. Awakura
  QCM Studies of Chemical Solution Deposition of ZnO in Aqueous Media Containing Zinc Nitrate and Dimethylamineborane
  J. Electrochem. Soc., 153(11), C735-C740 (2006).
• K. Arai, S. Hagiwara, S. Takayama, K. Murase, T. Hirato, Y. Awakura
  Galvanic Contact Deposition of CdTe from Ammoniacal Basic Electrolytes at Elevated Temperatures using an Autoclave-type Vessel
  Electrochem. Commun., 8(4), 605-609 (2006).
• K. Arai, K. Murase, T. Hirato, Y. Awakura
  Studies of Oxidation Bbehaviors of CdTe in Ammoniacal Basic Electrolytes
  Electrochim. Acta, 51(23), 4987-4993 (2006).
• K. Arai, K. Murase, T. Hirato, and Y. Awakura
  Effect of Chloride Ions on Electrodeposition of CdTe from Ammoniacal Basic Electrolytes
  J. Electrochem. Soc., 153(2), C121-C126 (2006).
• K. Murase, Y. Tanaka, T. Hirato, and Y. Awakura
  Electrochemical Quartz Crystal Microbalance Studies of CdTe Formation and Dissolution in Ammoniacal Basic Aqueous Electrolytes
  J. Electrochem. Soc., 152(5), C304-C309 (2005).
• K. Arai, S. Hagiwara, K. Murase, T. Hirato, and Y. Awakura
  Galvanic Contact Deposition of CdTe Layers using Ammoniacal Basic Aqueous Solution
  J. Electrochem. Soc., 152(4), C237-C242 (2005).
• M. Miyake, K. Murase, H. Inui, T. Hirato, and Y. Awakura
  Analytical TEM Study of CdTe Layer Electrodeposited from Basic Ammoniacal Aqueous Electrolyte
  J. Electrochem. Soc., 151(3), C712-C715 (2004).
• M. Miyake, K. Murase, H. Inui, T. Hirato, and Y. Awakura
  Comparison of Microstructures of CdTe Layers Electrodeposited from Basic Ammoniacal and Acidic Sulfate Electrolytes
  J. Electrochem. Soc., 151(3), C168-C175 (2004).
• M. Miyake, K. Murase, T. Hirato, and Y. Awakura
  Hall Effect Measurements on CdTe Layers Electrodeposited from Acidic Aqueous Electrolyte
  J. Electroanal. Chem., 562, 247-253 (2004).
• M. Miyake, K. Murase, T. Hirato, and Y. Awakura
  Electrical Properties of CdTe Layers Electrodeposited from Ammoniacal Basic Electrolytes
  J. Electrochem. Soc., 150(6), C413-C419 (2003).
• K. Murase, M. Matsui, M. Miyake, T. Hirato, and Y. Awakura
  Photoassisted Electrodeposition of CdTe Layer from Ammoniacal Basic Aqueous Solutions
  J. Electrochem. Soc., 150(1), C44-C51 (2003).
• M. Miyake, K. Murase, T. Hirato, and Y. Awakura
  Effect of Anions on Electrodeposition of CdTe from Ammonia-alkaline Solutions
  Surf. Coat. Technol., 169/170, 108-111 (2003).
• K. Murase, T. Honda, M. Yamamoto, T. Hirato, and Y. Awakura
  Electrodeposition of CdTe from Basic Aqueous Solutions Containing Ethylenediamine
  J. Electrochem. Soc., 148(3), C203-C210 (2001).
• K. Murase, H. Watanabe, S. Mori, T. Hirato, and Y. Awakura
  Control of Composition and Conduction Type of CdTe Film Electrodeposited from Ammonia Alkaline Aqueous Solutions
  J. Electrochem. Soc., 146(12), 4477-4484 (1999).
• K. Murase, H. Watanabe, T. Hirato, and Y. Awakura
  Potential-pH Diagram of the Cd-Te-NH₃-H₂O System and Electrodeposition Behavior of CdTe from Ammoniacal Alkaline Baths
  J. Electrochem. Soc., 146(5), 1798-1803 (1999).
• K. Murase, H. Uchida, T. Hirato, and Y. Awakura
  Electrodeposition of CdTe Films from Ammoniacal Aqueous Solution at Low Cathodic Overpotentials
  J. Electrochem. Soc., 146(2), 531-536 (1999).

Schematic view of CdS | CdTe solar cell

CdTe layer electrodeposited from basic bath

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Composite electrodeposition using nonaqueous and aqueous media

Electrochemical formation of aluminium coating is usually conducted using organic solvents and inorganic AlCl₃-based molten salts. However, the flammability of organic solvents and the high vapor pressure of AlCl₃ are drawbacks of these media. As an alternative, we selected an AlCl₃/dimethylsulfone (DMSO₂) molten mixture for the electrodeposition of Al.

Dimethylsulfone

Such a nonaqueous bath is suitable for composite electroplating of metals with hydrophilic inorganic particles, since agglomeration of the particles sometimes takes place in aqueous electrolytes. Using the AlCl₃/DMSO₂ bath, we succeeded in obtaining agglomerate-free composite coating of Al with micrometer and nanometer-sized SiO₂, SiC, Al₂O₃, TiB₂, and BN particles.
Composite electrodeposition using aqueous media is also under investigation.

-- Selected papers --

• J. Fransaer, E. Leunis, T. Hirato, and J.-P. Celis
  Aluminium Composite Coatings Containing Micrometre and Nanometre-sized Particles Electroplated from a Non-aqueous Electrolyte
  J. Appl. Electrochem., 32(2), 123-128 (2002).
• T. Hirato, J. Fransaer, and J.-P. Celis
  The Electrolytic Codeposition of Silica Particles with Alminium from AlCl₃-Dimethylsulfone Electrolytes
  J. Electrochem. Soc., 148(4), C280-C283 (2001).

SEM micrograph of Al/SiO₂ composite coating

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Electrodeposition of metals and alloys from novel ionic liquids

Room temperature molten salts, or ionic liquids, are promising solvents for ﾒgreen chemistry,ﾓ owing to their nonflammable and nonvolatile nature. Although electrodeposition of Al and Al-alloys using ionic liquids is well-investigated, hygroscopic chloroaluminate-based liquids employed here are difficult to handle. To avoid hygroscopicity, ionic liquids comprising fluoroanions have been developed. We are investigating electrodeposition and fundamental electrochemical behaviors of metals in a novel series of hydrophobic ionic liquids synthesized by a combination of aliphatic ammonium cations and amide anion. It was found that Cu, Ni, Zn, and Mg can be electrodeposited from trimethyl-n-hexylammonium bis((tri-fluoromethyl)sulfonyl)amide (TMHA-Tf₂N) liquid, which has a wide electrochemical window of 5.6 V.

-- Selected papers --

• T. Katase, K. Murase, T. Hirato, and Y. Awakura
  Redox and Transport Behaviors of Cu(I) Ions in TMHA-Tf₂N Ionic Liquid Solution
  J. Appl. Electrochem., 37(3), 339-344 (2007).
• T. Katase, R. Kurosaki, K. Murase, T. Hirato, Y. Awakura
  Formation of Cu-Sn Alloy Layer by Contact Deposition Using Quaternary Ammonium Imide Type Ionic Liquid
  Electrochem. Solid-State Lett., 9(4), C60-C72 (2006).
• T. Katase, S. Imashuku, K. Murase, T. Hirato, and Y. Awakura
  Water Content and Related Physical Properties of Aliphatic Quaternary Ammonium Imide-Type Ionic Liquid containing Metal Ions
  Sci. Technol. Adv. Mater., 7(6), 502-510 (2006).
• T. Katase, R. Kurosaki, K. Murase, T. Hirato, Y. Awakura
  Formation of Cu-Sn Alloy Layer by Contact Deposition Using Quaternary Ammonium Imide Type Ionic Liquid
  Electrochem. Solid-State Lett., 9(4), C60-C72 (2006).
• T. Katase, T. Onishi, S. Imashuku, K. Murase, T. Hirato, and Y. Awakura
  Water Content and Properties of Aliphatic Ammonium Imide-Type Room Temperature Ionic Liquid Containing Metal Ions
  Electrochemistry, 73(8), 686-691 (2005).
• K. Murase and Y. Awakura
  Electrodeposition of Metals from Quaternary Ammonium Imide Type Room Temperature Ionic Liquid
  Trans. Mater. Res. Soc. Jpn., 29(1), 55-58 (2004).
• K. Murase, K. Nitta, T. Hirato, and Y. Awakura
  Electrochemical Behavior of Copper in Trimethyl-n-hexylammonium Bis((trifluoromethyl)sulfonyl)amide, an Ammonium Imide-type Room Temperature Molten SaltRoom Temperature Molten Salt
  J. Appl. Electrochem., 31(10), 1089-1094 (2001).

Trimethyl-n-hexylammonium bis((trifluoromethyl)sulfonyl)amide (TMHA-Tf₂N or TMHA-TFSI)

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Electrochemical alloy formation for corrosion-resistant coatings

Ni-Mo alloy plating has been investigated as an alternative to hard chromium coating. Electrodeposition of Ni-Mo alloy is categorized as ﾒinduced codeposition,ﾓ where molybdenum, which cannot be electrodeposited as an elemental form from aqueous media, is codeposited as an alloy with iron-group hyper-transition metals, i.e. Ni, Co, Fe. Although the mechanism for induced deposition has been a subject of scientific interest, most reports to date deduced the mechanism based on the behavior of alloy deposition or on the characteristics of resulting deposits. There has been no attention to the relationship between the dissolving regime of metal ions in the electroplating bath and alloy deposition behaviors, since electroplating baths, which contains not only metal ions but also complexing agents and some additives, are usually too concentrated and complicated to analyze. For acidic Ni-Mo plating baths, we determined the distribution of complexed metal ions by factor analysis of a set of their visible absorption and Raman spectra. Here, we have concluded that the domination of 1:1 complexes of Ni(II) and Mo(VI) with citrate is important for alloy deposition.
We are also working on (a) a new alloy formation technique on steel surface by pulse electrolysis and (b) a fast Zn-Cr electrodeposition onto steel at high current densities.

-- Selected papers --

• S. Yagi, A. Kawakami, K. Murase, and Y. Awakura
  Ni-Mo Alloying of Nickel Surface by Alternating Pulsed Electrolysis Using Molybdenum(VI) Bath
  Electrochim. Acta, 52(19), 6041-6051 (2007).
• S. Yagi, K. Murase, T. Hirato, and Y. Awakura
  Alternating Pulsed Electrolysis for Iron-Chromium Alloy Coatings with Continuous Composition Gradient
  J. Electrochem. Soc. 154(6), D304-D309 (2007).
• S. Yagi, K. Murase, T. Hirato, Y. Awakura
  Fe-Cr Alloying of Iron Surface by Asymmetric Alternating Pulsed Electrolysis using Trivalent Chromium Solution
  Electrochem. Solid-State Lett., 9(5), B32-B34 (2006)
• K. Murase, M. Ogawa, T. Hirato, and Y. Awakura
  Design of Acidic Ni-Mo Alloy Plating Baths Using a Set of Apparent Equilibrium Constants
  J. Electrochem. Soc., 151(12), C798-C805 (2004).
• T. Hirato, Y. Yamamoto, and Y. Awakura
  A New Surface Modification Process of Steel by Pulse Electrolysis with Asymmetric Alternating Potential
  Surf. Coat. Technol., 169/170, 135-138 (2003).
• M. Miyake, T. Hirato, E. Matsubata, Y. Awakura
  Structure of Zn-Cr Alloy Electrodeposited on Steel at High Current Densities
  Proceeding of the 2nd International Conference on Processing Materials for Properties, B. Mishra and C. Yamauchi (eds.), TMS, Warrendale, 2000, pp. 779-782.
• K. Murase, H. Ando, E. Matsubara, T. Hirato, and Y. Awakura
  Determination of Mo(VI) Species and Composition in Ni-Mo Alloy Plating Baths by Raman Spectra Factor Analysis
  J. Electrochem. Soc., 146(6), 2210-2217 (2000).
• K. Murase, T. Honda, T. Hirato, and Y. Awakura
  Measurement of pH in the Vicinity of a Cathode during the Chloride-Electrowinning of Nickel
  Metall. Mater. Trans., Sect. B, 29, 1193-1198 (1998).
• K. Shinoda, E. Matsubara, M. Saito, Y. Waseda, T. Hirato, Y. Awakura
  Structural Study of Poly-molybdate Ions in Acid Mo-Ni Aqueous Solutions
  Z. Naturforsch., Sect. A, 52, 855-862 (1998).
• E. Uekawa, K. Murase, E. Matsubara, T. Hirato, and Y. Awakura
  Determination of Chemical Species and their Composition in Ni-Mo Alloy Plating Baths by Factor Analysis of Visible Absorption Spectra
  J. Electrochem. Soc., 145(2), 523-528 (1998).

Integrated Raman system for the measurements of electrolytic baths

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Fuel cell at intermdiate temperature since 2005

Current focus is technology and science for intermideate temperature fuel cell which can be operacted from 200 to 500 C. Especially, my strong interest is electrochemistry and thermochemistry of fuel cell using solid phosphate and proton conducting oxide as electrolyte.

-- Related papers and presentations--

• High-Performance Solid Acid Fuel Cells Through Humidity Stabilization
  D. A. Boysen, T. Uda, C. R. I. Chisholm, and S. M. Haile
  Science, 303, 68-70 (2004).
• Thermodynamic, thermomechanical, and Electrochemical Evaluation of CsHSO₄
  T. Uda, D. A. Boysen, and S. M. Haile
  Solid State Ionics, 176, 127-133 (2005).
• Thin-Membrane Solid-Acid Fuel Cell
  T. Uda and S. M. Haile
  Electrochem. Solid-State Lett., 8, A245-A246 (2005).
• Thermodynamic Analysis and Conductivity of Yttrium Doped Barium Zirconate
  T. Uda, P. Babilo, and S. M. Haile,
  Solid Oxide Fuel Cel IX with 207th Meeting of The Electrochemical Socieety (ECS), Quebec, Canada (2005), May 15-20.
• Alcohol Fuel Cell at Optimal Temperatures
  T. Uda, D. A. Boysen, C. R. I. Chisholm, and S. M. Haile
  Electrochem. Solid-State Lett., 9, A261-A264 (2005).

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Instrumentation

• Potentiostat/Galvanostat systems (Hokuto Denko, Seiko EG&G, ALS)
• X-ray diffractometer (Rigaku)
• X-ray fluorescence spectrometer (Shimadzu)
• ICP-atomic emission spectrometer (Seiko)
• Laser Raman system (Kaiser Optic)
• UV-visible spectrophotometer (Hitachi)
• Laser microscope system (Lasertec, Nikon)
• Integrated surface texture and contour measuring system (Tokyo Seimitsu)

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