bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrodeposition of Dense Tungsten Films from Molten KF-KCl-WO3 and Csf-Cscl-WO3
Authors: Nohira Toshiyuki , Meng Xianduo , Ide Tatsuya , Norikawa Yutaro , Yasuda Kouji 
Published: May 2020

Tungsten metal is known for its robustness, especially high melting and boiling points and hardness. However, its hardness and brittleness make it difficult to work. Thus, electrodeposition of dense tungsten films is worth investigating. There are a number of reports on the electrodepositon of tungsten from high temperature molten salts such as fluorides, chlorides, oxides, etc. It is known that dense and coherent tungsten deposits are more easily obtained from molten fluorides compared to molten chlorides. Although good tungsten deposits can be electrodeposited from molten oxides, the operation temperature tends to be high, typically over 1123 K. One drawback of typical fluoride melts like LiF-NaF-KF is difficulty in removing the adhered molten salts by water washing because LiF and NaF have limited solubility to water.
From this background, we proposed new electrolyte baths, molten KF-KCl and CsF-CsCl. Since all the components salts of KF, KCl, CsF and CsCl have large solubility to water, adhered salts to deposited films can be easily removed by water washing.
First, electrodeposition of tungsten was investigated in eutectic KF–KCl melt to which WO3 was added at 923 K. Cyclic voltammograms at copper and gold electrodes indicated the deposition of tungsten metal at more negative potential than 1.55 V vs. K+/K. The effects of electrolysis conditions on the morphology of deposits were studied by changing the cathodic current density from 12.5 to100 mA cm-2. As shown in Fig.1 (a), a dense tungsten film with a thickness of approximately 20 µm was obtained on a copper substrate electrode at 12.5 mA cm−2 for 120 min. From the Raman spectra of molten KF–KCl and molten KF–KCl–WO3 at 923 K, the coordination structure of W(VI) complex ion was indicated to be fac-[WO3F3]3−.
Secondly, eutectic CsF-CsCl melt was used to lower the operation temperature. After adding 2.0 mol% of WO3, the electrodeposition was investigated using copper and gold electrodes at 823-923K. As shown in Fig.1 (b), a dense and smoother tungsten film was obtained by galvanostatic electrolysis at 12.5 mA cm−2 for 120 min at 873 K.

Figure 1
Electrochemical Growth and OER Catalytic Activityof Ultrathin Epitaxial Cobalt Oxide Films
Authors: Pacheco Ivan , Bouvier Mathilde , Wiegmann Tim , Qiu Canrong , Reikowski Finn , Stettner Jochim , Magnussen Olaf M. , Allongue Philippe , Maroun Fouad 
Published: May 2020

Iron-group oxides are among the best earth abundant catalysts for the oxygen evolution reaction (OER) in alkaline and neutral electrolytes [1],[2]. Such oxides have been prepared with an amorphous or a crystalline structure, using thermal salt decomposition [3], autoclave synthesis [4], photochemical reactions [5], sol-gel synthesis [6], metal electrodeposition and subsequent oxidation, [7] and direct oxide electrodeposition [1], [8].
This work focuses on well-defined epitaxial CoOx [9] electrocatalysts grown by direct electrodeposition on Au(111) according to an approach similar to that introduced by Switzer [8]. The growth modes of catalysts and the mechanisms of deposition will be discussed based on electrochemical characterizations, XRD characterizations and microscopic observations. In particular to explain that CoOOH may be obtained at a potential of +1V/RHE by oxidation of a Co(II) complex diluted in an alkaline solution while thermodynamics predicts that Co3O4 should be formed. The electrochemical properties in pre-OER and within OER will be discussed as a function of the surface structure and morphology of layers. In particular to show that the large pseudocapacitance measured at the electrode is not related to its ECSA but to electrical charging within the bulk of the electrode.
[1] M. W. Kanan and D. G. Nocera, Science 321, 1072 (2008).
[2] C. C. L. McCrory, S. Jung, I. M. Ferrer et al., Journal of the American Chemical Society 137, 4347 (2015).
[3] C. Pirovano and S. Trasatti, Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 180, 171 (1984).
[4] D. Yuming, H. Kun, Y. Lin et al., Nanotechnology 18, 435602 (2007).
[5] S. R. Alvarado, Y. Guo, T. P. A. Ruberu et al., The Journal of Physical Chemistry C 116, 10382 (2012).
[6] A. Bergmann, E. Martinez-Moreno, D. Teschner et al., Nature Communications 6, 8625 (2015).
[7] M. W. Louie and A. T. Bell, Journal of the American Chemical Society 135, 12329 (2013).
[8] J. A. Koza, Z. He, A. S. Miller et al., Chem. Mat. 24, 3567 (2012).
[9] F. Reikowski, F. Maroun, I. Pacheco et al., ACS Catalysis 9, 3811 (2019).
Anodic TiO2 Nanotube Layers As Scaffolds for Deposition of Functional Materials
Authors: Bawab Bilal , Krbal Milos , Prikryl Jan , Zazpe Raul , Sopha Hanna , Macak Jan M. 
Published: May 2020

The self-organized 1D TiO2 nanotubular layers have attracted considerable scientific and technological interest over the past two decades, all motivated by a great performance in the range of applications including photo-catalysis, solar cells, hydrogen generation and biomedical uses [1,2]. The synthesis of these nanotubular layers has been carried out by a conventional electrochemical anodization of Ti sheet. Except the 1D character, these nanotubes possess unique features such as tunable dimensionality, structural flexibility, unidirectional electron transport through nanotube walls, chemical and mechanical stability and biocompatibility.
One of the major application targets of TiO2 nanotubes has been their utilization as scaffolds or templates for deposition of secondary materials towards new applications [3]. In particular, for the photoelectrochemical applications (e.g. photovoltaics) ordered nanostructures, such as self-organized TiO2 nanotubes, offer the advantage of directed charge transport and controlled phase separation between the donor and acceptor materials, unlike within randomly ordered mesoporous TiO2 supports.
Numerous techniques were utilized for this purpose, such as for example hydrothermal routes, electrodeposition or Atomic Layer Deposition (ALD) techniques. Electrodeposition is very powerful technique to deposit metals [4], oxides [5] or other rather complex materials (such as CuInSe2 [6]) within the nanotubes various by means of complete filling or decoration with. On the other hand, ALD can deposit the widest range of secondary materials within TiO2 nanotubes by means of homogenous coatings [7-10]. ALD is the only technique of choice to coat in particular high-aspect ratio nanotube layers. Overall, the deposited materials influence strongly photo-electrochemical properties of nanotube layers.
The presentation will be focused in detail on TiO2 nanotube layers of various aspect ratios filled, decorated or coated by various chalcogenide-based materials using electrodeposition and ALD. Experimental details and some very recent photo-electrochemical and structural characterizations of a new type of heterostructured photo-chemical cell will be presented and discussed.
References
1] J.M. Macak et al., Curr.
Opin. Solid State Mater. Sci.,
2007
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1-2, 3-17.
2] K.Lee, A. Mazare, P. Schmuki, Chem.
Rev., 2014, 114, 9385-9454.
3] J.M. Macak, Chapter 3 in: D. Losic and A. Santos, Electrochemically Engineered Nanoporous Structures, Springer International Publishing, Switzerland, 2015

4] J. M. Macak, B.G. Gong, M. Hueppe, P. Schmuki, Adv. Mater., 2007, 19, 3027.
5] L. Wu & G. Zangari, J. Phys. Chem. C,
2010, 114, 1155
6] S. Das & J. M. Macak et al., ChemElectroChem, 2017, 4, 495
7] R. Zazpe et al, Langmuir, 2016, 32, 10551
8] S. Ng et al., Adv. Eng. Mater., DOI: 10.1002/adem.201700589
9] R.Zazpe et al., Nanoscale, 2018, 10, 16601-16612.
10] F. Dvorak et al., Appl. Mater. Today,
2019
, 14, 1-20.
Effects of Coordination Structure of Silicon Ions on Electrodeposition Process of Silicon in Fluoride Melts
Authors: Suzuki Yuta , Inoue Yosuke , Yokota Masayuki , Fukunaka Yasuhiro , Goto Takuya 
Published: May 2020

Silicon electrodeposition in molten salts is a key technology for fabricating silicon films, as a material for solar cells, by environmentally friendly and inexpensive processes. We have already reported the electrodeposition of silicon films from SiO2 in fluoride melts. However, there are only few studies about the effects of ions in fluoride melts, such as O2- anion, and Li+/Na+/K+ cations, on silicon electrodeposition processes. In particular, it is important to understand the coordination structure of silicon ions for controlling the nucleation and growth processes between solid metal substrates and fluoride melts interface.
In this study, we investigated the electrodeposition of silicon from SiO2 in LiF-NaF-KF melts mixed with Li2O as a source of O2- anion at 873 K, and binary LiF-KF, LiF-NaF, and NaF-KF melts. The results of the in-situ Raman spectroscopy and DFT calculations indicated that the O2− anions could cleave the Si-O-Si bonds of SiO2 or silicate ions such as [Si2O5]2−; consequently, the formation of tetrahedron [SiO3F]3− species was promoted. In addition, electrochemical measurements, XRD, SEM, and EDS analysis showed thickness and current efficiency of electrodeposited polycrystalline silicon was affected by the difference in coordination structures of silicon ions in fluoride melts. This study suggested the design of the molten salts bath was significant for controlling interfacial phenomena at electrode/molten salts to fabricate high-quality Si layers with high current efﬁciency.
Amalgam Protection for Alkali Metal Anodes
Authors: He Guang , Li Qingwen , Zhang Qi , Ding Yi 
Published: May 2020

The dendrite issue and the associated cell degradation problems have proved to be a key challenge to the practical application of alkali metal anodes.1,2 We present a simple yet efficient approach to fabricate amalgam anodes (Figure 1a) that afford long-term stability cycling at practical current densities and capacities.3 The amalgam layer allows fast electron transfer as well as Li/Na/K migration at the electrolyte-electrode interphase, which significantly promote the cycling performance. For example, Protected Li electrodes exhibit stable cycling over 750 hrs at high plating current and capacity of 8 mA cm-2 and 8 mAh cm-2 in symmetric cells (Figure 1b). Coupled with high-loading cathodes (~12 mg cm-2) such as LiFePO4 (LFP) and LiNi0.6Co0.2Mn0.2O2 (NCM), the prototype full cells also demonstrate much improved rate and long-term cycling stability (Figure 1c). In-situ optical microscopy analyses confirm the dendrite nucleation and growth can be remarkably suppressed with the Li-Hg protected anodes (Figure 1d). These promising results provide new perspectives on the regulation of sodium electrodeposition and hence the elimination of the dendritic morphology for the practical development of alkali metal batteries.
References:
1. X.-B. Cheng, R. Zhang, C.-Z. Zhao, and Q. Zhang, Chem. Rev., 117, 10403–10473 (2017).
2. R. Weber, M. Genovese, A. J. Louli, S. Hames, C. Martin, I. G. Hill, and J. R. Dahn, Nat. Energy, 4, 683-689 (2019).
3. G. He, Q. Li, Y. Shen, and Y. Ding, Angew. Chem. Int. Ed., DOI: 10.1002/anie.201911800 (2019).

Figure 1. a) The preparation process of Li-Hg protected anodes; b) Cycling performance of Li-Hg protected anodes and pristine anodes in symmetric cells; c) Cycling performance of Li-Hg protected anodes and pristine anodes in full cells with high-loading LFP and NCM cathodes; d) In-situ optical analyses showing the different Li deposition behaviors on Li-Hg protected and pristine anodes.

Figure 1
Integrated Hybrid Fuel Cell-Battery Power Generator Enabled through Electrochemical Hydrolysis of Nanoporous Aluminum
Authors: Corsi John S , Fu Jintao , Lee Timothy , Detsi Eric 
Published: May 2020

Over the past decade, tremendous progress has been made in transitioning from fossil fuel-based transportation to electric vehicles powered either by lithium-ion battery (LIB) or proton-exchange membrane (PEM) fuel cell technologies. A hybrid fuel cell-battery power generation system is more attractive than a battery alone, or a fuel cell alone, since a battery is able to meet the high-power requirements during peak demands (e.g. acceleration), while a fuel cell can be used as a range extender. Existing hybrid PEM fuel cell-battery power generation systems consist of separate LIB and PEM fuel cell systems that are coupled together. In this configuration, the hydrogen used to feed the PEM fuel cell is stored on-board in high-pressure tank.
In this talk, I will present our novel integrated hybrid PEM fuel cell-battery power generation system, which can simultaneously produce both electricity, acting as a battery, and hydrogen gas, which is then used to directly feed a PEM fuel cell, from a single device. We have previously reported the scalable synthesis of novel bulk nearly oxide-free nanoporous aluminum (NP-Al) and the ability to produce hydrogen gas through “chemical” hydrolysis of NP-Al in pure water, with solid aluminum hydroxide, hydrogen gas and heat as the only reaction products. [1] The new hybrid power system proposed here builds on this work through the introduction of a novel cell configuration which facilitates the spontaneous “electrochemical” hydrolysis of NP-Al, during which aluminum is oxidized at the anode, electrons from this oxidation reaction diffuse through an external circuit to the cathode where hydrogen evolution takes place, meanwhile electricity is also generated from electrons flowing through the external circuit. This electricity is the equivalent of the heat generated during chemical hydrolysis reaction, meaning that during electrochemical hydrolysis, the only reaction products in case of 100 % reaction efficiency are solid aluminum hydroxide, hydrogen gas and electricity without heat. In this talk, I will discuss this novel cell, current progress and outlook for future development.

Reference:

[1] Corsi JS, Fu J, Wang Z, Lee T, Ng AK, Detsi E. (2019). Hierarchical Bulk Nanoporous Aluminum for On-Site Generation of Hydrogen by Hydrolysis in Pure Water and Combustion of Solid Fuels. ACS Sustainable Chemistry and Engineering, 7, 11194–11204. doi.org/10.1021/acssuschemeng.9b00481
Nucleation, Pattern Development, and Fidelity in the Photoelectrodeposition of Se-Te Nanostructures
Authors: Simonoff Ethan , Van Munoz Lorenzo , Papadantonakis Kimberly , Lewis Nathan S 
Published: May 2020

The electrochemical growth of Se-Te under polarized illumination results in anisotropic, highly-ordered lamellar nanostructures, tunable by input wavelength. This spontaneous growth occurs at room temperature, in an isotropic solution, with no templating or chemically-directing agents, and with mW-cm-2 illumination intensity with no requirement for coherency. The deposition process is compatible with a wide variety of conductive substrates and can be performed over large areas of unpatterned substrates. However, pattern fidelities in these films are generally low. Improving the potentially broad applicability of this patterning method requires an understanding of pattern development and of factors contributing to the long-range order of films deposited through this phenomenon.
Methods of quantifying pattern fidelity have been developed using Fourier-transform (FT) analysis of large-area images of photoelectrodeposited Se-Te films. Nominally identical illumination conditions during the deposition of Se-Te on crystalline (111)-oriented Si substrates doped degenerately with either p- or n-type dopants produced a variation in the morphology of Se-Te films. Films deposited on p+-Si generally displayed much less defective patterns, with a higher degree of anisotropy and a more well-defined pattern period versus films deposited on n+-Si. These results are attributed to the energetics at the dynamic junction formed by growing Se-Te and the Si substrate.
Analysis of film morphologies at early levels of mass addition to growth substrates elucidate the mechanism by which junction energetics affect resulting film morphologies. Higher nucleation densities are generally observed under conditions that produced Se-Te films with relatively higher pattern fidelities. Control of pattern fidelity by control of nucleation density, through substrate choice and tuning of applied deposition potential, is demonstrated.
Rational Compositional Control of Electrodeposited Ag-Fe Films
Authors: Sun Yunkai , Zangari Giovanni 
Published: May 2020

In the field of alloys, be they bulk of thin films, systematic control of composition is a prerequisite to understand details of microstructure evolution and phase transformation. Because of the complete immiscibility of Ag-Fe, electrodeposition is capable of forming metastable structures, enabling an economical alternative to synthesis from vacuum methods. However, due to the negative redox potential of Fe(II)/Fe, Fe cations must be complexed in order to prevent the formation of hydroxides in the deposit. On the other hand, due to the difference in redox potential, Ag(I) will be spontaneously reduced by the plain Fe(II) bath due to the reaction Fe(II)/Fe(III). Using Fe(III) could prevent the spontaneous reduction of Ag(I) in the solution, however, hydroxides could form due to the small stability constant of Fe(OH)3. Furthermore, the fast Ag(I) reduction rate could lead to the formation of dendrites, an unfavorable morphology for achieving uniform and smooth alloy films. In order to achieve films with high quality, dimethylhydantoin (DMH) was used as a surfactants and complexation agents for Ag(I).
Herein we demonstrate the paradigm for designing this novel alkaline DMH-citrate for Ag-Fe deposition, compare the prediction from available thermodynamic data with the observed CV profiles of different baths, and rationalize its composition control at the limiting current range. Two aspects are highlighted:

Stabilization of the deposition bath: the solution instability is dominated by the redox pairs of Ag(I)/Ag and Fe(II)/Fe(III). Using plain Fe(II)/Ag(I) citrate-DMH solution, we observed gradual degrading of deposition bath with high Fe(II) concentration. Based on the mixed potential theory, Fe(III) is added to positively shift the redox potential of Fe(III)/Fe(II). By adding 1%at,Fe(II) of Fe(III), the open-circuit potential positively shifted for 0.07V and loss of Ag(I) in the solution was partially resolved.

Prediction of composition: after stabilization of the bath, the film composition at the limiting current condition could be predicted using a limiting current mass-transfer ratio. Small deviations from this prediction were found, probably caused by solution instability and formation of Fe(II) hydroxide species due to high pH.

In summary, we would like to draw attention to the electrodeposition process by highlighting the importance of complexation chemistry, that unusually here has the purpose of stabilizing the electrolyte with multivalent cations.

Graphical abstract:
Calculation results of redox potentials related to the DMH-citrate complexed Ag-Fe electrolyte based on the Nernst equation and thermodynamic data available, with the redox pair which influences the solution stability marked with arrows in the plot. The stabilized bath possesses a well-behaved linear trend between solution concentration ratio and film (deposited at limiting current condition) composition ratio.

Figure 1
(Invited) Film Properties of Various Electroless Plated Co Alloy Films Formed on SiO2/Si Substrate and Its Interdiffusion Properties Against Cu
Authors: Shingubara Shoso , Matsudaira Taro , Shimizu Tomohiro 
Published: May 2020

There is a serious problem of poor side wall coverage for the sputtered barrier metals in high aspect ratio TSVs. We have proposed electroless plated Co-alloy barrier metals for TSV. For this purpose, we prepared various CoB and CoWB alloys with different atomic compositions and crystalline structures. Furthermore, we evaluated interdiffusion properties of Cu/Co-alloy/Si stacked structure by SIMS analysis. It turned out that the electroless CoWB film containing larger amount of W has excellent diffusion barrier property than other CoWB films with smaller W content.
We formed electroless barrier films of CoB and CoWB using Pd nanoparticle catalyst on SiO2/Si substrate [1]. For evaluation of Cu interdiffusion properties by SIMS, we deposited Cu and TiN thin films successively by sputtering on the barrier film. The ratio of the atomic composition was changed by adjusting the ratio of cobalt sulfate, tungstic acid, and some other contents of the plating bath. SIMS depth profiles of CoB (Fig.1-a) and CoWB films after annealing at 400 ℃ (Fig.1-b) are shown in Fig.1. There was a large interdiffusion between Cu and CoB after 400 ℃ annealing (Fig.1-a). Co-Silicide formation significantly occurred and Si atoms diffused into CoB layer. However, interdiffusion was significantly suppressed in the case of Co-20%W-B film (Fig.1-b). These results suggest that W atoms existed in CoWB have a strong effect of suppressing Cu diffusion in Co film, and CoWB with 20 atom % W showed a good diffusion barrier property. The present study suggests that the electroless plated CoWB having a larger W content has a high potential as a diffusion barrier film for the via last TSV process.
[1] F. Inoue, T.Shimizu, F.Miyake, R.Arima, T.Ito, H.Seki, Y.Shinozaki, T.Yamamto, and S.Shingubara, Microelectronic Engineering, 106 (2013) 164–167.
[2] T. Iseri, S.Shindo, Y.Miyachi, A.Hirate, S.Tanaka, T.Shimizu, T.Ito, S.Shingubara, Jpn. J. Appl. Phys. 57 (2018), 07MB02-1~6.

Figure 1
Electrodeposition Transition Metal Alloy Films for Magnetic Thermometry
Authors: Rus Eric D , Dennis Cindi L , Moffat Thomas P 
Published: May 2020

Knowledge of the temperature distribution within three dimensional volumes is of great importance to applications in many fields, but there does not currently exist a method for microscale temperature measurement throughout a volume. As part of an effort to develop methodology for 3D thermometry, the present work seeks to develop materials and structures with temperature-dependent magnetic properties that provide optimal sensitivity in the 200 K to 400 K range, leveraging previous work which demonstrated compositional control of alloys films by varying the deposition potential.[1] Preliminary room temperature vibrating sample magnetometry measurements on a series of platinum nickel alloy films showed ferromagnetic behavior for samples deposited at more reducing potentials (higher nickel content) and paramagnetic behavior for samples deposited at more positive potentials (higher platinum content). Herein, we will discuss deposition and characterization of these films with an emphasis on factors affecting their temperature-dependent magnetic properties.
[1] J. J. Mallett, E. B. Svedberg, J. E. Bonevich, A. J. Shapiro, W. F. Egelhoff, T.P. Moffat, J. Electrochem. Soc., 2008, 155, D1-D9.
Electrodeoxidation of Iron Oxide in Aqueous NaOH Electrolyte
Authors: Haarberg Geir Martin , Khalaghi Babak 
Published: May 2020

The production of iron and steel contributes to ~10 % of global CO2 emissions. Electrolysis is an alternative route to eliminate CO2 formation. Experiments were carried out in NaOH-H2O (50-50 wt%) electrolyte with a suspension of Fe2O3 particles at ~100 oC. A rotating disk electrode was used as the cathode. Different cathode substrates of different graphite qualities and silver were used. The current efficiency for iron deposition was consistently higher than 90 %. Silver was found to be an excellent substrate for good quality deposits.
Cathodes in the form of pellets of hematite were also found to be reduced to iron by electrodeoxidation in the same electrolyte. Bauxite residue is a waste product from the Bayer process to produce aluminium oxide. The high content of iron oxide makes it a candidate for electrodeoxidation in a similar way.