bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maintaining the Momentum in Electrochemical Energy and Power Conversion
Authors: Brodd Ralph 
Published: February 2020

Battery technology has reached goals that were considered by many as impossible only 15 years ago. The pace of new developments has accelerated along with the entrance of people with exceptional skills who have been drawn into the technology. I would like to take you back in time to when I entered the arena and relate some of my observations as a means to encourage you to keep up the momentum and remarkable growth that has lead to the use of electrochemical energy and power conversion in our every day personal life. We’ve seen the promise of electric cars fulfilled, solar, and wind power to replace coal fired power plants in order to control global warming. In many respects electrochemical energy conversion (batteries, fuel cells, flow batteries, capacitors, etc.) has become the hope of the future in maintaining our world as we know it.
My journey started at the University of Texas with, Professor, Dr. Norman Hackerman, in 1950. While at the university, The Corrosion Division of the ECS sponsored an essay contest. I entered, and won first place and membership in the ECS in 1952. (the rest is history, so to speak)
My PhD thesis was on the relationship of capacitance and surface area of electrodes. This work continued at the National Bureau of Standards (now NIST) using impedance as a function of frequency to determine the characteristics (rate constants, exchange current, activation energy, etc.) of battery electrode reactions. Today, impedance is being used to sort cells in a production environment and to identify and remove individual problem cells in large array Li-Ion cell systems to prevent an “incident”. Lithium ion batteries are an essential part of our lives and also offer the promise of lowering greenhouse emissions in transportation and utility applications.
A word about lessons learned in my career during the development of the alkaline Zn-MnO2 cell and the birth of lithium technology. I pushed very hard to increase funding for lithium exploration over that for alkaline as a key for the future. We re-engineered the alkaline technology with new MnO2 materials, a new separator, a new anode current collector, and a new seal to prevent leakage. These were all ready for implementation. Finally, the company President said, “Ralph I understand your enthusiasm and outlook, but we need to have a viable and continuing income from alkaline cells to ensure our future.” The new current collector was adopted because it would instantly because it lowered cost and instantly saved over a million dollars annually. The MnO2 research work continued and eventually resulted in new cathode materials for Li-Ion cells.
Influence of Temperature on Electroless Copper Deposition from Formaldehyde-Containing Solutions Using 2-Hydroxy-1,2,3-Propanetricarboxylic Acid As Cu(II) Ligand
Authors: Kepeniene Virginija , Stagniunaite Raminta , Stalnioniene Irena , Norkus Eugenijus 
Published: February 2020

Electroless coating technique is one of the ways to obtain metallic coatings in which there is no usage of electric current. The industrial electroless copper plating solution containing formaldehyde as reducing agent are known from the middle of the last century and are widespread in the practice up to now. Electroless copper coatings are deposited on plastics, ceramics, polymers and other non-conductig materials. However many chemical compounds used in technological processes are hazardous for total environment, therefore the efforts are made to displace those substances with less hazardous or purely harmless compounds. Citric acid (2-hydroxy-1,2,3-propanetricarboxylic acid), forming sufficiently stable complexes with copper (II) ions in alkaline solutions, was found to be a suitable ligand for copper(II) chelating in alkaline (pH > 12) electroless copper deposition solutions.
The substrate was a smooth Pt sheet (1´1 cm) electroplated with Cu for 20 min from acid copper solution (1.0 mol l-1 CuSO4 + 0.5 mol l-1 H2SO4) at 1.5 A dm-2. Before the electroless plating the electroplated substrate was activated for 30 s in acid PdCl2 solution (1 g l-1). The main electroless copper plating experiments were carried out for 30 or 60 min. in 50 ml of the solution containing (mol l-1): CuSO4×5H2O – 0.05; citrate – 0.3; formaldehyde – 0.15.
Our studies were carried out in electroless plating solutions at pH 12.0 – 13.0 and 10 – 30 °C temperature. It was found that the autocatalytic reduction of Cu(II) by formaldehyde from Cu(II)-citrate solutions containing begins at pH above 12 and accelerates with a further increase in pH and temperature. The thickness of the compact copper coatings obtained under optimal operating conditions in 1 h can reach ca. 3 μm. From Cu(II)-citrate solutions deposited copper coatings real surface areas (R
f) vary widely, i. e. from ca. 2.5 up to 15.0. The maximum R
f values were obtained at pH 12.5 solution at 20 °C temperature. Results were compared with those for systems operating with other copper (II) ligands.
Fabrication of FePt and CoPt Magnetic Nanodot Arrays by Electrodeposition Process
Authors: Homma Takayuki , Wodarz Siggi , Nishiie Daiki , Otani Tomohiro , Ge Siyuan , Zangari Giovanni 
Published: February 2020

Electrodeposition processes have been extensively used to fabricate various magnetic thin films and micro/nano structures. We have attempted to utilize these processes to form magnetic nanodot arrays for use in bit patterned media (BPM) applications [1,2] for ultra-high density magnetic recording. In this paper, we will discuss our recent results on the synthesis of magnetic nanodot arrays using electrochemical deposition, focusing on FePt and CoPt.
Patterned substrates with nanopore arrays were prepared by electron beam lithography (EBL), which has the capability to form smaller-scale patterns, as well as by UV-nanoimprint lithography (UV-NIL), with larger size but high throughput. N-Si(100) wafer covered with sputter deposited Cu or Ru was used as a substrate. Electrodeposition of CoPt [3] was successfully carried out into the patterned nanopores to form arrays with 20 nm diameter dots, and fabrication of even smaller dots with <10 nm diameter has been performed. In order to achieve precise control of growth, the initial stage of the deposition process was investigated in detail, and correlation between deposition conditions such as applied potential and microstructure of the deposited dots were studied. Based upon these results, we attempted to fabricate nanodot arrays using electrodeposition of FePt, which is expected to exhibit higher perpendicular coercivity, Hc, due to the formation of the fct L10 structure. Application of FePt to BPM has been widely studied, mainly using arrays of discrete nanoparticles [2]. Based upon the bath described in previous studies [4,5], deposition conditions were optimized. It was found that layered deposition of Fe-rich and Pt-rich regions, followed by RTA (rapid thermal annealing) process was most effective in forming the L10 structure, resulting in higher Hc at thinner thickness region; in particular, a Hc of 12 kOe was obtained at < 20 nm thick films. By using this method, the patterned deposition of FePt was attempted and the array with 15 nm diameter dots was formed, the structure of which has been maintained after the annealing process.
This work was financially supported in part by Grant-in-Aid for Scientific Research, MEXT, Japan and by The Storage Research Consortium.
[1] D. Weller et. al, Appl. Phys. Lett. 88, 222512 (2006).
[2] B. D. Terris, T. Thomson, J. Phys. D: Appl. Phys., 38, R199 (2005).
[3] T. Ouchi, Y. Arikawa, Y. Konishi, T. Homma, Electrochim. Acta, 55, 8081 (2010).
[4] D. Liang, J. J. Mallett, G. Zangari, J. Electrochem. Soc., 158,149 (2011).
[5] S. Wodarz, Y. Maniwa, H. Hagiwara, T. Otani, D. Nishiie, G. Zangari, T. Homma, IEICE Tech. Rep., MR2013-20, 7 (2013).
Advancements in Electroplated Co-Pt Thick Film Micromagnets
Authors: Oniku Ololade D. , Garraud Alexandra , Arnold David P 
Published: February 2020

There are enormous opportunities to employ permanent magnets to establish strong magnetic fields or field gradients in microsystem applications such as microactuators, microsensors, biological cell manipulation, micro power generators, etc. [1]. These applications motivate the development of microfabrication methods to realize high-remanence, high-coercivity magnetic structures in a dimensional “gap” between traditional bulk materials (usually >1 mm) and thin films (usually <1 mm).
In this work, we summarize advancements in electroplated Co-Pt alloys as candidate materials for wafer-level integration into magnetic microsystems. As a fabrication technology, electrodeposition offers advantages of speed, cost, and process integrability. Compared to other magnetic materials, Co-Pt alloys offer good energy density, high Curie temperature, and high corrosion-resistance. Specific attention is focused on the Co-rich composition (Co80Pt20) as well as the equiatomic composition (Co50Pt50) in the ordered L10phase, as shown in Figure 1.
Electroplated Co80Pt20 affords hard magnetic properties in the as-deposited magnetic state, without the need for any high-temperature processing steps. The material exhibits an hcp structure with large magnetocrystalline anisotropy, and by careful selection of the seed layer, significant out-of-plane texture (perpendicular anisotropy) can be achieved. For example, we have shown films up to 18 mm thick with Hci = 330 kA/m (4 kOe), Br = 1.0 T, and BHmax = 130 kJ/m3(16 MGOe) [2]. One potential drawback of this material is high sensitivity to temperature [3].
In contrast, L10 CoPt requires a high-temperature annealing step (~700°C) to induce a transformation from a disordered fcc atomic arrangement to an ordered L10 structure. This transformation results in strong magnetocrystalline anisotropy, but the material exhibits an overall isotropic behavior due to the random arrangement of the polycrystalline grains. For example, we have demonstrated 15-mm-thick photolithographically patterned magnets with Hci = 800 kA/m (10 kOe), Br = 0.8 T, and BHmax = 150 kJ/m3(19 MGOe) [4].
This talk will expound on the electrodeposition of these two alloys and the resultant magnetic properties. The usage of these films in example microsystem applications will also be presented.
[1] O. Cugat, J. Delamare, and G. Reyne, “Magnetic micro-actuators and systems (MAGMAS),” IEEE Trans. Magn., 39, 3607-3612 (2003)
[2] O. D. Oniku and D. P. Arnold, “Microfabrication of high-performance thick Co80Pt20 permanent magnets for microsystems applications,” ECS Trans., 50(10), 167-174 (2012)
[3] A. Garraud, E. Shorman, O. D. Oniku, B. Qi, and D. P. Arnold, “Influence of temperature on the magnetic properties of electroplated Co-rich Co–Pt thick films,” J. Micromech. Microeng., 24(1), 017002 (2014)
[4] O. D. Oniku, B. Qi, and D. P. Arnold, “Electroplated L10 CoPt thick-film permanent magnets,” J. Appl. Phys., 115(17), 17E521 (2014)
Influence of Morphology and Domain Structure on Mechanical Stress in High, Electroplated Co-Fe Flux Guides
Authors: Kruppe Rahel Maria , Rissing Lutz 
Published: February 2020

The most notable advantage electroplated binary Co-Fe alloys offer for MEMS applications like sensors and actuators is the high saturation flux density, which may reach values of 2.4 T in a composition range of 50 – 70 % Fe. In contrast, there are certain disadvantages limiting the use of these alloys, e. g. high film stress, high corrosion sensitivity and high magnetostriction. This triggered a lot of research aiming at the minimization of these unfavorable properties (1-4, 6).
In previous studies (5), we examined very high (20 µm) ring-shaped Co-Fe flux guide structures for a 3D, ultra-thin magnetic field sensor. Due to the GMR sensors underneath the flux guides, a thermal treatment at temperatures above 150°C to reduce film stress was not possible. Other measures were taken instead, like the use of saccharin, reverse pulse plating and the application of a magnetic field during deposition (2, 6). Thus, saturation flux densities above 2.1 T with drastically lowered film stress and good corrosion behavior were achieved, which may be attributed for a great part to the magnetohydrodynamic (MHD)-effect generated by the applied magnetic field. The gained results still necessitate further investigation of the connection between the process conditions and the mechanical and magnetic properties of the films. The goal is to maximize BS and the squareness of the hysteresis loop γ as well as to further reduce film stress σ and the coercivity Hc.
The mechanical and magnetic properties of Co-Fe films influence each other strongly. They are determined by the films’ microstructure, given by the film texture, grain size and morphology, structural defects and impurities. In this study, the effect of process conditions like current density, pulse duration, duty cycle, pH of the plating bath and application of a constant magnetic field parallel to the electrode surface on film stress, microstructure and magnetic properties are examined. The data for film stress, calculated on the basis of profilometry and x-ray diffraction (XRD) measurements, and the data for magnetic properties (saturation flux density, coercivity, hysteresis loop squareness) are linked together and will be referenced with the associated parameters for film texture, grain size and morphology – determined with XRD, scanning electron microscopy (SEM) and atomic force microscopy (AFM) – as well as magnetic domain structure, observed with Kerr microscopy.
Figure 1: a) Top view of electroplated flux guide b) B-H-loops of flux guides c) domain pattern of flux guide

E. I. Cooper, C.Bonhote, J. Heidemann et. al., IBM J. Res. Dev., 49, p. 103 (2005) 2005

J. A. Koza, M. Uhlemann, A. Gebert et. al., Electrochim.
Acta, 53, p. 5344 (2008)

W. Szmaja, W. Kozłowski, K. Polański et. al., Mat.
Chem. Phys., 132, p. 1060 (2012)

M. Zieliński, Int. J. Electrochem. Sci., 8, p. 12192 (2013)

R. Kruppe, A. Wienecke and L. Rissing, Trans. Mag, 50 (4), (2013)

S. Riemer, J. Gong, M. Sun et. al., J. Electrochem. Soc., 156 (10), D439 (2009)
Magnetic Properties of Cobalt Nanowires and Nanotubes
Authors: Lu Jia Grace , Bergmann Gerd , Thompson Richard 
Published: February 2020

Development of novel magnetic materials has played an important role in modern day science and technology. Nanomagnetism research not only sparks interests in fundamental physics, but also renders promising technological applications. Ferromagnetic Co nanowires, synthesized via low voltage electrodeposition method. High resolution transmission electron microscopy and x-ray diffraction results show that the nanowires are uniform in size, and consist predominantly hcp structure with the magnetocrystalline easy axis (c-axis) perpendicular to the wire axis. SQUID measurement illustrates the dominance of shape anisotropy, manifested by the weak temperature dependence of the enhanced coercive field along the wire axis. Furthermore, the magnetic domain structures of individual, segmented or multiple nanowires are studied via magnetic force microscopy. It shows a strong dipole at the ends of the wire, together with a spatial magnetization modulation along the wire with a period around 700 nm. Based on theoretical modeling, such intrinsic modulation originates from the competition between the magnetocrystalline polarization along the easy axis and the shape anisotropy along the wire axis. Low temperature magnetoresistance measurement shows irreversible magnetization switching in addition to the anisotropic behavior due to magnetization orientation dependent electron scattering.
On the other hand, Cobalt nanotube arrays embedded in hexagonally ordered anodic aluminum oxide templates are fabricated by direct electrodeposition with low current density under several mA/cm2. The wall thickness is about 15 nm and outer diameters are in accordance with pore diameter around 80 nm. Nearly 100% filling rate is achieved which benefits from the through pores which enable the efficient penetration of electrolyte. Transmission electron microscopy and selected-area electron diffraction are performed to show that the nanotubes are predominantly hcp single crystals with c-axis (easy axis) perpendicular to the tube axis. SQUID and MFM results indicate that the magnetization follows a circumferential direction around the tube, which is manifested in the weak magnetic signal in the MFM imaging as well as a sheared hysteresis dependence for field applied along the tube axis. This phenomenon has been confirmed by theoretical modeling taking into account the magnetocrystalline, shape demagnetization and magnetic exchange energies.
Polymeric Gel Electrolyte Based on a Rotaxane-Networked Polymer with Alkyl Magnesium Bromide and Ionic Liquid for Rechargeable Mg Batteries
Authors: Yoshimoto Nobuko , Yamabuki Kazuhiro , Kim Intae , Shigematsu Ryou , Tsutsumi Hiromori 
Published: February 2020

Rechargeable magnesium (Mg) battery that uses metal Mg as the negative electrode is a potential candidate of the next-generation power sources for electric vehicles (EV) and other large scale applications. We previously reported that Mg is reversibly deposited and dissolved on a metal substrate in mixed solutions containing ionic liquid and alkyl magnesium bromide [1]. However, as the electrolyte system contains high vapor pressure THF, the resulting battery will have still practical problems in safety and reliability. Recently, we have synthesized a novel network polymer with a rotaxane structure, a complex consisting of secondary ammonium salt and 24-membered crown ether component [2]. In this study, a novel gel electrolyte based on a rotaxane-networked polymer has been prepared, in which ethyl magnesium bromide dissolved in triethylene glycol dimethyl ether (C2H5MgBr/Triglyme) and N,N-diethyl-N-methyl- N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl) imide (DEMETFSI) were included. The ionic conductance behavior and electrochemical behavior of the resulting gel electrolytes were investigated.
A “rotaxane network” was synthesized in the same manner as our previous report [2] (Fig.1). The gel electrolytes were prepared by an impregnation method: the polymer film was immersed in the mixed solution of C2H5MgBr/Triglyme and DEMETFSI for 24 h. The resulting network polymer maintained the stable shape without decomposing after a month’s impregnation in 1M C2H5MgBr/Triglyme.
The “rotaxane network” polymeric gel electrolyte impregnated in C2H5MgBr/ Triglyme + DEMETFSI exhibited an ionic conductivity of 2.8×10-4 S cm-1 at 20°C (swelling degree = ca. 60%). Highly reversible behavior was observed for cathodic deposition and anodic dissolution of Mg in this polymeric gel electrolyte system.
Acknowledgment
This research was financially supported by the Japan Science and Technology Agency (JST), Advanced Low Carbon Technology Research and Development Program (ALCA).
References
[1] N. Yoshimoto, M. Matsumoto, M. Egashira, and M. Morita, J. Power Sources, 195, 2096(2010).
[2] K. Yamabuki, K. Onimura, and T. Oishi, Polymer Journal, 40, 205(2008).
Application of Al-Doped LLTO Solid Electrolyte Prepared By Sol-Gel Method in Lithium-Oxygen Batteries
Authors: Le Hang T.T. , Jadhav Harsharaj S. , Kalubarme Ramchandra S. , Jang Seong-Yong , Park Chan-Jin 
Published: February 2020

To date, lithium lanthanum titanate (LLTO) of the nominal formula Li3xLa2/3-x
1/3-2xTiO3 with perovskite structure have been considered to be promising solid electrolyte materials for lithium-oxygen battery due to a numerous outstanding advantages such as: (i) a high lithium conductivity at room temperature, (ii) a high lithium diffusion coefficient, (iii) a low electronic conductivity, and (iv) an electrochemical window larger than 4 V. However, the LLTO materials have also suffered from a few disadvantages such as insufficient total conductivity due to the large grain boundary resistance and difficulty in controlling Li+ content and Li+ conductivity of the materials especially after exposure to high annealing temperature. In addition, when the LLTO contacts directly with Li metal, Ti4+ in LLTO can be reduced into Ti3+ by metallic Li leading to increase in the electron conductivity of LLTO.
In this study, we investigated the feasibility of application of Al-doped LLTO ceramics with nominal formula of (Li1/3La5/9)1.005Ti0.99Al0.01O3 (denoted as A-LLTO) in Li–O2 batteries. A-LLTO was synthesized using sol-gel modified Pechini method in the aim of (i) reducing the synthesis temperature (up to 300-400 oC compared to the conventional solid state reaction method); (ii) lessening loss of lithium and gaining homogeneous mixture easily. As referred above, since LLTO cannot contacts directly with Li metal, prior to being assembled in organic- type Li-O2 battery as an electrolyte separator On the A-LLTO ceramics with 16 mm diameter and 200 m thickness, a thin protective layer of LiPON of 200 nm in thickness was sputtered for separation of A-LLTO from the Li metal anode. The perovskite material was used as catalyst for cathode material of the batteries.
The XRD patterns of A-LLTO ceramics obtained after annealing were compared and matched with Li0.33La0.56TiO3 (Code: 01-087-0935; Tetragonal) confirming purely the tetragonal crystalline structure P4/mmm space group of perovskite phase without secondary phases. After polished and heat etched at, the surface of the ceramics was observed using SEM. T ceramics was composed of grains of typical rectangle shape connected together closely. The largest grain size reached 100 m.
Ionic conductivity of A-LLTO measured using electrochemical impedance spectroscopy (EIS) exhibited the relatively high conductivity of 3.17 10-4 S/cm. This is attributed to the low total activation energy of 0.358 eV and the somewhat large crystal grain size compared with ceramics prepared at the same temperature.
The Li-O2 cells employing the A-LLTO ceramic electrolytes were tested in galvanostatic and constant capacity mode. Effect of current density and operating temperature on the charge-discharge behavior of Li-O2 cell was investigated. The Li-O2 cell employing A-LLTO electrolyte layer exhibited the satisfactory performance.