bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of Zn-Co-Terephthalate MOF and Its Conversion to Co-Doped ZnO Thin Films
Authors: Nakamura Tensho , Kudo Hana , Tsuda Yuki , Yoshida Tsukasa
Published: May 2020

Energy security and sustainability are the most important challenges of mankind for their survival towards the 22nd century. While renewable electricity by solar and wind has already become so cheap, technologies for its conversion to easily storable chemical energies are urgently needed. Electrocatalysts not dependent on noble metals therefore need to be developed.

We have recently succeeded in microwave (MW)-assisted hydrothermal synthesis of Co-doped ZnO nanoparticles, which exhibit catalytic activity towards water oxidation superior to Co3O4, although the electrode prepared by paste coating faced problems of its stability due to imperfect connection of the particles [1]. Electrodeposition can overcome this problem since well crystallized, stable and perfectly conducting ZnO thin films can be obtained. However, it is not at all straightforward to dope cobalt because of the large different of solubility (K
sp = 5.92 × 10-15 and 3 × 10-17 for Co(OH)2 and Zn(OH)2, respectively), so that almost pure ZnO is solely electrodeposited even in the presence of Co2+ ions in the bath.

Taking advantage of structural flexibility of metal-organic framework (MOF) could be a possible solution to achieve co-precipitation of Zn and Co. We have recently achieved cathodic electrodeposition of Zn-terephthalate (TPA) MOF thin films by addition a TPA into the ZnO electrodeposition bath [2]. Layered MOF structure was self-assembled during precipitation by bridging of double-layered Zn hydroxide with TPA.

Herein, we report successful electrodeposition Zn-Co-TPA MOF precursor thin films and its conversion to oxides to yield Co-doped ZnO. Compositional and structural characterization as well as their electrocatalytic activities for oxygen evolution reaction (OER) are discussed.

Potentiostatic electrolysis at an F-doped SnO2 (FTO) coated glass rotating disk electrode (RDE, ω = 500 rpm) was carried out at -1.0 V (vs. Ag/AgCl) in an O2-saturated aqueous electrolyte (70ºC) containing 5 mM ZnCl2, 200 μM TPA, and 0,5 mM CoCl2, for 30min. The film was annealed at 450℃ for 1 hour, under air.

A white film electrodeposited in the presence of CoCl2 turned into green film after annealing, as expected for the formation of Co-doped ZnO. (Fig. 1a). X-ray diffraction pattern (XRD, Fig. 1b) indicates electrodeposition of Zn-TPA MOF and their conversion of ZnO after annealing both in the presence and absence of Co. The absorption spectra of the films on the other hand show clear difference between the samples, for which the one with Co and after annealing exhibit clear red-shift of onset for bandgap absorption and characteristic triple peaks at about 560, 610 and 650 nm arising from d-d transition of doped Co(II) ions (Fig. 1c). These features were commonly found for the Co-doped ZnO nanoparticles by MW reaction, so that similar or superior OER catalysis can be expected for the sample prepared by electrodeposition in this study.

Figure 1
Nucleation and Growth in Electrochemically Deposited Metals
Authors: Pawar Gorakh M , Wang Xuefeng , Li Yejing , Fang Chengcheng , Lin Yuxiao , Zhang Minghao , Lu Bingyu , Banerjee Abhik , Liu Ping , Dufek Eric J. , Meng Y. Shirley , Liaw Boryann
Published: May 2020

Electrochemical deposition of metals, such as Li, Na, K, Zn, Mg and alike, are very important for energy storage and rechargeable battery applications. Yet, the fundamental understanding of the deposition process of these metals is surprisingly overlooked and lacking. It is often observed that the deposit’s morphology, microstructure, and the associated properties are often controlled by the kinetic processes that govern the evolution of these properties with time. However, the mechanism and mechanistic processes involved are difficult to characterize to yield quantitative and sufficiently detailed temporal information to help us understand the underlying principles that govern the phase lattice structural and morphological changes. Here, we applied reactive molecular dynamics (r-MD) simulation to model the nucleation and growth processes of Li metal deposition in typical electrochemical cells. Cryo-EM was used to characterize the microstructure, morphology and relevant properties of the Li metal deposits obtained from a range of current density and duration. Both cryo-TEM and r-MD results suggest that the Li deposits are likely amorphous in the initial deposition and such amorphous phase was retained more easily at lower current density such as 0.1 mA cm-2 than those at 1 mA cm-2. The r-MD simulation explained the cause of such amorphous phase retention is due to the significantly longer phase transition time associated with the transition from the disordered amorphous phase to the ordered crystalline phase of body-centered cubic (bcc) lattice structure. Such a long incubation could be easily understood, but hardly emphasized in the literature. Therefore, this critical aspect was often overlooked in the discussion of the experimental results, where kinetic effects are dominating the processes in the observations. We registered similar observations in other electrochemical metal depositions, and this thermal-activation-inhibited incubation process is being observed in all experimental conditions disregarding which elemental metal and lattice structure involved. The implication of this fundamental understanding will be discussed in this presentation.
Electrochemical Atomic Layer Deposition: Self-Terminated Electrodeposition Reactions
Authors: Moffat Thomas P , Liu Yihua , Ahn Sang Hyun , Ritzert Nicole L. , Wang Rongyue , Gillette Eleanor , Gokcen Dincer , Hangarter Carlos M , Bertocci Ugo , You Hoydoo
Published: May 2020

Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. Common to all these systems is the role of reaction intermediates, namely adsorbed H or OH-, in the quenching of metal deposition reactions. Further details on the mechanisms of self-terminated deposition reactions will be discussed. Likewise, the utility and relevance of the process to the synthesis of nanoparticles and thin films, and the study of bimetallic electrocatalysts will be detailed.
Structure – Reactivity - Relationship in Nanostructured and Amorphous Aluminium Lanthanoid Material Libraries
Authors: Hassel Achim Walter , Shahzad Khurram , Recktenwald Dominik , Mardare Cezarina Cela , Kollender Jan Philipp , Mardare Andrei Ionut
Published: May 2020

The lanthanoids are a consequent series of elements and with their 3 valence electrons they prefer the trivalent state while continuously filling the inner f-shell. A specific energetically stabilizing effect is observed so that the empty, the half-filled or the completely filled f-shell show extraordinary low energies resulting in a stabilizing effect so that neighboring valence states such as divalent or tetravalent can be also observed. Interestingly with increasing atomic number the atomic and ionic radii decrease - counter intuitively. As a result of the electronic shielding effect of the f-electrons the so-called lanthanoid contraction is observed.

Aluminium is another element that forms preferentially trivalent ions. A combinatorial approach in which aluminium-lanthanoid-alloys are investigated both in terms of the alloy itself but in particular for the passivity based on the mixed oxides forming on these alloys is presented here. A complex attempt was made not only to cover the various elements themselves but also their concentration ratios in material thin film libraries. These material libraries are prepared in a large preparation and analysis cluster the so-called CALMAR. Asymmetrical physical codeposition of the constituting elements is used in HV and UHV chambers to prepare these libraries and to characterize them by a scanning EDX system as well as XRD.

Theoretical considerations were used to compute the Pourbaix diagrams. Also phase diagrams of the Al-Lx alloys are consulted to identify intermetallics and regions of solid solution mixing.

Passivation studies were performed using a flow type scanning droplet cell microscope FT-SDCM. This method allows the subsequent stepwise anodization and electrochemical impedance spectroscopy characterisation of a single spot of a library having a single composition. Spatial scanning of the library yields detailed information of the systematically changing alloy compositions. To understand not only the anodic oxide formation but also the chemical and electrochemical reactions during anodization a complementary investigation of the electrolyte is performed using inductively coupled plasma spectrometry.

Various lanthanoids were mixed with aluminium and electrochemically studied. It is found that the large ionic radii mismatch is likely to cause strong amorphisation. In this way already binary alloys were found to form metallic glasses in some regions i.e. for some compositions. This has a strong impact on the passivation behavior and electrochemical stability. Some distinct intermetallic compounds in these binary alloys were found with the expected consequence for the stability.
Experimental and Computational Investigations of Pulsed Electrodeposition of Well-Adhered Nanocatalysts on Conductive Materials for Energy Applications
Authors: Karimi Shahram
Published: May 2020

Electrical energy storage has emerged as a critical component in North America’s clean energy transformation. Vehicle electrification and integration of renewables such as wind and solar power into the grid have further underlined the importance of affordable, durable and environmentally friendly energy storage platforms. Rechargeable batteries, including Li-ion and metal-air batteries, have been receiving significant attention as well as criticism for their relatively high cost and sluggish oxygen reduction reaction, respectively. Accordingly, investigation into the development of catalysts with high activity, long life, and low cost has become an area of active research.

Nanocatalysts such as cobalt, nickel and platinum-group metals were electrodeposited on various conductive substrates, including carbon paper, carbon cloth and highly-ordered titania nanotubes (TNTs). Catalyst electrodeposition was carried out employing pulse current electrodeposition with various waveforms, low duty cycles, and high peak deposition current densities. All catalysts were systematically characterized and tested using microscopy, spectroscopy and electrochemical techniques. The presence of nanocatalysts were confirmed by SEM and XRD and were found to be 2-5 nm for platinum and platinum-group metals and 10-50 nm for nickel and cobalt on carbon substrates and TNTs, respectively.

A comprehensive mathematical model based on progressive nucleation was developed to elucidate the roles of various process parameters, including pulse waveform, peak deposition current density and duty cycle on the size and catalytic activity of the resulting nanocatalysts in different environments. The model considers some key contributing factors towards growth current and, ultimately, nucleation, including diffusion, ohmic and charge transfer phenomena as well as varying diffusion coefficients during electrodeposition. Model predictions were confirmed by experimental measurements especially on platinum-group metals deposited on carbon substrates for use in PEM fuel cells and bi-functional nanocatalysts for use in aluminum-air batteries.
Reexamination of Nucleation and Growth Behavior of Zn during Zincating on Al: Role of Nitric Acid Etching
Authors: Ghosh Subir Kumar , Pachchigar Vivek , Kain Vivekanand
Published: May 2020

Deposition of various coatings on Al surface is required for variety of functional applications such as for better corrosion resistance, improvement in conductivity, wear resistance etc. These coatings are normally applied on Al surface followed by well-known zincating process (galvanic displacement) in order to obtain subsequent adherent overlayer coatings. Adhesion of these overlayers depends on uniformity of Zn films on Al surface and researchers normally follow either single zincating or double zincating process to eliminate oxide layer interference. However, it has been established over the years that double zincating is a better technique in comparison to single zincating to produce a uniform Zn-films on Al surface. It is to mention here that Al substrate undergoes nitric acid dip followed by single zincating prior to double zincating and is a very important step. A quiet good amount of research has already been devoted to obtain various adherent coatings on Al and Al-alloys and to analyze the nucleation mechanism during single and double zincating processes. However, the underline mechanism of nitric acid etching and its role on subsequent Zn-nucleation is yet to be fully understood. In view of this, in the present study, a systematic effort has been made to elucidate the role of nitric acid etching followed by single zincating on Zn nucleation and growth mechanism during subsequent second zincating. For this, we have studied the time-dependent zinc nucleation on 99.95% pure Al during single as well as double zincating. These Zn-nucleation and growth behavior on Al surface was monitored using AFM, FESEM and FIB-cut cross section image investigations in detail. Difference in nucleation and growth pattern of Zn on Al during two zincating processes was analyzed. Apart from these, the porous surface obtained after nitric acid dissolution was investigated in depth under AFM and FESEM along with EDS. Non-gravimetric method such as Rutherford Backscattering Spectrometry (RBS) was used to determine the deposition rate of Zn during competitive galvanic deposition of Zn and alkaline dissolution of Al while zincating. The Zn grain size obtained from AFM image was verified by GIXRD analysis. Open circuit potential (OCP) was monitored during single as well as double galvanic displacement processes to understand Zn nucleation behavior and correlated with the morphological data. The observed results will be discussed in terms of electrochemical processes involved, change in chemical nature of the Al surface and porous layer formation due to nitric acid etching and thermodynamic supersaturation on Zn nucleation.

Figure 1
Pulse Plating of Zinc for Highly Efficient Rechargeable Metal Redox Flow Batteries
Authors: Accogli Alessandra , Bertoli Luca , Panzeri Gabriele , Gibertini Eugenio , Magagnin Luca
Published: May 2020

In current research, electrochemical energy storage systems have gaining interest because they constitute an essential element in the development of sustainable energy technologies. Among them, rechargeable flow batteries (RFBs) are one of the most promising technology for the integration in grid-connected electricity, especially if combined with unpredictable and intermittent renewable energy sources, due to their high efficiency, power/energy independent sizing and room temperature operation. At the moment, among all RFBs systems, the most investigated and advanced technology is the vanadium based RFB, characterized by an energy efficiency equal to 80% and energy density ranging 15-45 Wh/l. However, nowadays the main bulk of research is focused on finding an economically convenient and technically competitive flow battery chemistry, able to ensure long lifetime and high energy efficiency. A zinc-iron RFB with low cost and high energy density will be presented. In particular, inorganic electrolytes based on high soluble salts have been developed, achieving a charge density of 30-70 Wh/l. The electrochemical nucleation and growth of zinc onto a carbon felt current collector in continuous and pulse charging of the battery is studied, showing the achievable improvements in terms of efficiencies and stability of the RFB over charging time. The combination of high energy efficiency of the Zn-Fe RFB with its ability to withstand a large number of charge/discharge cycles and the low cost, makes this battery system suitable for energy storage applications.
High Stability Dimethyl Sulfoxide/ Zinc Triflate Electrolyte for Zinc-Ion Batteries
Authors: Kao-Ian Wathanyu , Kheawhom Soorathep
Published: May 2020

The increasing global requirement for energy and the possible environmental impact of increased energy usage require cleaner, safer, and more economical energy storage technologies. Lithium-ion batteries (LIBs) are commonly recognized as the most viable options. Nonetheless, their limitations on material abundance, high cost, and safety issues are the main concerned. Therefore, other battery developments need to be developed. Zinc-ion batteries (ZIBs) have recently attracted attention due to their high safety, environmental friendliness, and low cost. Previously, aqueous-based ZIBs have been the focus of attention. Nevertheless, the problems regarding hydrogen evolution and zinc electrode passivation, along with dendrite development, limit their practical application. Herein, a stable and low-cost electrolyte, based on dimethyl sulfoxide (DMSO) and zinc triflate (Zn(Otf)2), is reported as an alternative electrolyte for rechargeable ZIBs based on alpha-type manganese oxide (α-MnO2) intercalation electrode. The behavior of the zinc electrode on stripping and deposition in the DMSO electrolyte is examined. Besides, the charge storage and charge-transfer characteristics of the battery are investigated. The results show that the DMSO-based electrolyte exhibits the lowest overpotential. Also, during long-term cycling, no sign of passivation and dendrite formation on the zinc electrode are observed. Consequently, the battery exhibits excellent electrochemical performance with the maximum specific capacity of 200 mAh/g and good cyclability. Besides,the results confirm the reversible intercalation/de-intercalation of Zn ion from the DMSO-based electrolyte into the α-MnO2 electrode. Overall, the proposed electrolyte system shows high potential for Zn/α-MnO2 battery system.

Figure 1
Electrodeposition of ZnNi Alloys from Ethylene Glycol for Corrosion Protection
Authors: Bernasconi Roberto , Firtin Gozde , Kahyaoglu Buse , Nobili Luca , Magagnin Luca
Published: May 2020

Zn rich ZnNi alloys electrodeposition have recently attracted the attention of researchers due to their interesting corrosion properties [1]. In particular, alloys containing Ni in the 15 - 25 % range find application in a number of industrial fields, like automotive and constructions. ZnNi is normally electrodeposited from aqueous solutions, in which plating takes place following a typical anomalous mechanism [2]. In the last few years, however, new deposition approaches have been attempted to improve ZnNi plating performances. Specifically, III generation deep eutectic solvents comprising choline chloride have been tested [3].

The present work investigates the use of non-aqueous ethylene glycol based electrolytes for the deposition of Zn rich ZnNi alloys. The use of ethylene glycol as solvent introduces many advantages with respect to aqueous solutions: low oxygen contamination, high deposits purity and no pH dependance [4]. ZnNi codeposition was studied employing cyclic voltammetry and layers were deposited under potentiostatic control. Deposition potential was varied and its influence on final composition and morphology was determined. Addition of an additive (NH4Cl) to enhance surface morphology was attempted as well [3]. Phase composition was investigated using XRD to determine the possible presence of a metastable γ-ZnNi phase, which has already been observed in the case of ZnNi plated from alkaline aqueous solution [5]. Finally, corrosion behavior of layers obtained from ethylene glycol was assessed and compared with equivalent coatings deposited from commercial aqueous solutions.

[1] M. Gavrila et al.; Surface and Coatings Technology, 123 (2-3), 164-172 (2000)

[2] G. Roventi et al.; Journal of Applied Electrochemistry 30 (2), 173–179 (2000)

[3] S Fashu et al.; Transactions of Nonferrous Metals Society of China 25 (6), 2054-2064 (2015)

[4] G. Panzeri et al.; Electrochimica Acta 271 (1), 576-581 (2018)

[5] S. Ieffa et al.; Transactions of the IMF 94, 321-324 (2014)
Electrodeposition of Stoichiometric CdTe from a Reusable Ionic Liquid Bath
Authors: Patel Dipal B , Mukhopadhyay Indrajit , Chauhan Khushbu
Published: May 2020

Electrodeposition (ED) from ionic liquid (IL) medium is of much importance because a variety of architectures can be synthesized by IL assisted growth. However, these liquids are relatively new for the fabrication of compounds and alloys with a great control over the stoichiometry and thickness. In this regard a well-defined route needs to be established for their wider acceptance as greener alternatives to deposit materials like CdTe, CdS, CdSe, etc. via ED. In this article, we have discussed the prerequisites, tricks and methodology to develop stoichiometric CdTe thin films from IL medium with required thicknesses in a highly controlled way compared to conventional ED techniques. This method provides a greener alternative to aqueous electrolytes which are considered to be hazardous media for the ED of CdTe films. We have found that the required precursor ratio of Te:Cd can be lower down to 1:10 for [Bmim]Cl IL medium which is 1:1000 for the aqueous electrolytes. As-grown nanostructured CdTe films can be directly utilized for the devices like IR sensors, Schottky rectifiers and Solar cells without any post-annealing. Moreover, the aspect ratio of nanostructures can be tuned by changing the precursors’ ratio in IL bath. Nevertheless, IL can be reused multiple times to develop identical thin films which guarantee the low cost pathway.
Study on the Electrodeposition of Trivalent Chromium Plating Bath in the Presence of Oxalate Anions
Authors: Orozco German , Torres-González Julieta , Fernandez Dennys
Published: May 2020

Chromium is not easily electrodeposited from aqueous solutions based on trivalent chromium. Hull cell is employed to determine the optimum bath composition, and several electroplating baths were evaluated. The new bath with oxalate and acetate anions produces very good coatings and our results are valuable for the electroplating community and electrochemists. The baths presented a current efficiency of 37%, high covering power at 8.2 cm, low deposition potential of 7.3 V, and deposition rate of 0.4 μm/min. However, the Hull cell required a high current density (30 A/dm2). After 2 h of the electrodeposition process, the pH values change by 0.2 units. In addition, the baths were analyzed after electrolysis to detect Cr(VI), and this cation was not detected. Our study not only has a technological contribution but also presents a new explanation for the nature of these baths. In the literature, the usual explanation of the performance of these baths is based on the formation of complexes between ligands and Cr(III); however, our novel explanation is based on the high stability of water in the first solvation sphere of Cr(III), and we support our suggestions with several references to chromium solvation studies. The ligand-exchange reaction explanation is replaced by the second sphere hypothesis, that is, our explanation is based on the large stabilization energy of Cr−O bonds in [Cr(H2O)6]3+.

Figure 1
Prospects for Electrocatalytic Nitrate Reduction
Authors: Hatzell Marta C. , Lim JeongHoon
Published: May 2020

There is a growing imbalance in the nitrogen cycle, which is largely due to anthropogenic activities related to transportation and agriculture. This has resulted in a significant increase in both air and water based pollutants most commonly in the form of NOx, NH3, and NO3
-. Nitrate in groundwater is growing in concern globally, as it has significant impacts on public health. Today, current treatment strategies have largely focused on centralized biological treatment at wastewater treatment facilities. While effective, this requires the waste to be transported to the centralized facilities creating a large carbon footprint. Ideally, treatment of nitrate at the point source (location of farm runoff) could aid in containing the waste dispersion and could provide a way to recover nutrients necessary for agriculture.

Electrochemical remediation through electrocatalysis has been widely investigated for decades. However, the activity and selectivity for nitrate reduction on state of the art electrocatalyst has been limited. This has been ascribed to the sluggish kinetics (multi-electron transfer processes) and competition with hydrogen evolution reaction. Here we will explore the catalytic properties that need to be obtained for electrocatlytic nitrate reduction to be realized, and will highlight the role catalyst structure will play in achieving these goals. We will also detail an energy and exergy analysis, and will discuss the role systems engineering may play in advancing electrochemical nitrate remediation.
Generation of Virtual Microstructures for the Optimization of Lithium-Ion Battery Cathodes
Authors: Joos Jochen , Schmidt Adrian , Buchele Alexander , Weber André , Ivers-Tiffée Ellen
Published: May 2020

The microstructure of lithium-ion battery cathodes rules their performance. However, the production of a variety of cathodes with different microstructures through laboratory experiments is very expensive with respect to costs and time. Thus, model-based simulation approaches, i.e., virtual microstructures generated and analyzed on a computer, have become an important tool for microstructural optimization.

In this work, tools for the generation of realistic yet virtual microstructures are presented. Basically, three dimensional reconstructions of cathode microstructures are established by FIB tomography, and the individually shaped particles of the active material phase as well as the carbon black are extracted. A representative set of extracted particles is used to create structures with specified characteristics, such as e.g. the desired mass content of active material and conductive additive or specific particle size distributions. In combination with performance models, a preselection of promising design concepts can be conducted.

The complete workflow from the generation of realistic virtual microstructures based on 3D reconstruction via FIB tomography towards the simulation of discharge curves will be shown using the example of a commercial blend cathode consisting of the two active materials LiNiCoAlO2 (NCA) and LiCoO2 (LCO).

Figure 1
Operando Analysis of Bi/BiF3 Electrode Reaction in Li+/F- Hybrid Electrolyte By Synchrotron Radiation Diffraction
Authors: Fujimoto Hiroyuki , Kano Gentaro , Kiuchi Hisao , Shimoda Keiji , Kawasaki Mitsuo , Morigaki Ken-ichi , Kawauchi Shigehiro , Ogumi Zempachi , Abe Takeshi
Published: May 2020

1.Introduction

In recent years, the development of innovative batteries that exceed the performance of lithium-ion batteries has been desired. One of the candidates is a fluoride shuttle battery (FSB). It is an anion-based, rechargeable batteries operating under fluoride shuttling, and rests upon the foundation of a redox-active fluoride ion transporting electrolyte of high electrochemical stability. To realize the FSB, we have developed a lactone-based Li+/F- hybrid electrolyte, in which Li+ and F- ions that normally cannot coexist in organic solvents form some complexes soluble in GBL. The thus reformed electrolyte, together with its delicate and unique anion accepting (AA) function, largely expands the negative potential window to or beyond the standard redox potential of Li+/Li. In this study, in order to clarify the electrochemical behaviors of BiF3/Bi electrode combined with the electrolyte, the operando analysis was carried out by the synchrotron radiation diffraction (SRD) measurement.

2. Experimental

The BiF3 powder mixed with acetylene-black and PVdF was used as the working electrode. The activated carbon and Ag metal were used as the counter and reference electrodes, respectively. The Al-laminated half-cell composed of above-mentioned electrodes was assembled using a newly developed hybridized electrolyte. Thus prepared cell was pre-discharged (0th cycle) in advance in the potential range of -1.5 V – 1.0 V at ca. 0.04C. Then, several charge/discharge cycles were repeated with the same conditions. SRD was measured with BL28XU beam line at Super Photon ring-8, Japan during the whole charge/discharge process. High-energy X-ray with a wavelength of 0.049592 nm was used to obtain 2D diffraction patterns. The exposure time was set to 10 s, and several thousand diffraction profiles were obtained during the discharge/charge process. In order to analyze the obtained enormous profiles data in conjunction with the charge/discharge curves and their differential curves (V-dQ/dV), an analysis software called “Profile Chaser” was newly developed. By using the software, all the profiles of electrode during charge/discharge processes are loaded automatically in the computer. The profiles were successively displayed on a monitor as a series of profiles in conjunction of compositions estimated from the charge/discharge curves, so that the profile change was traced from the monitor.

3. Results and discussions

Fig.1 shows the SRD profile changes in the discharge process of 0th and 1st cycles. In both cycles, the intensity of 111 diffraction of BiF3 decreased and that of 012 diffraction of Bi increased as the discharge reaction proceeded. However, the formation of BiF3 was hardly observed in the charge process. It indicates that the bismuth fluoride formed in the charge process is amorphous or solved in the electrolyte.

Figure 1
Development and Application of Lithium Metal Phosphate to Achieve High Power Lithium-Ion Battery
Authors: Kanno Yusuke , Yanagita Hideo , Nakajima Satoshi , Suzuki Eiko , Ushirogochi Toru
Published: May 2020

Due to the increase of lithium-ion battery (LIB) capacity, LIBs have been widely applied to hybrid or pure electric vehicles (EVs) and stationary energy storages. Simultaneously, the requirements of LIBs performance (ex. safety, long cycle life and power performance) have also been increased. Focusing on the cathode active materials, lithium iron phosphate (LFP) is an attractive material which possesses an excellent thermal stability and long cycle life originated from its specific crystal structure of lithium metal phosphate [1]. Although the recent demand of LFP has been growing for different industrial uses, its low average potential (~3.4 V vs. Li/Li+) still remains a main issue. In this study, we developed a unique lithium metal phosphate that shows high average potential and excellent power performance. The power performance is contributed to its fast transport of lithium-ions in the original crystal structure consisted of three-dimensional framework. The synthesized material demonstrates promising electrochemical properties analyzed by different methods. Moreover, the synthesized material blended with another cathode active material results in a higher power performance of LIBs.

The lithium metal phosphate powder was synthesized by a liquid phase method. The electrode paste was prepared by mixing cathode active materials with carbon conductive agents and binders in N-methyl-2-pyrrolidone solvent. The paste was then used to prepare cathode on top of Al foil. Lithium metal foil or graphite anode electrode was used as a counter electrode. LiPF6 in organic carbonate solvent was used as electrolyte. The galvanostatic charge/discharge measurements were done at room temperature. Electrochemical impedance spectroscopy and cyclic voltammetry were used for analyzing lithium ion and electron transfer.

The experimental discharge capacity of the synthesized material matches with theoretical capacity calculated from the synthesized chemical composition, with a higher average potential than conventional LFP (~3.4 V). As for the power performance, the capacity retention rate of the fabricated LIB was over 80% at 50C discharge rate. In addition, the mixture of the synthesized material and another cathode active material showed a positive effect on the power performance of LIBs. Lastly, the synthesized material can be applied for use of inkjet printing systems attributed to its micrometer-size particle based on our accumulated technological expertise. Here, a detail discussion about the characteristics of the synthesized material will be reported in this meeting.

Reference

[1] N. Nitta et al., Mater.Today, 18, 252-264, 2015.
High-Voltage Sodium and Lithium Nitridophosphates axMy(PO3)3n As Cathode Materials for Sodium-Ion and Lithium-Ion Batteries
Authors: Wizner Agnieszka , Reynaud Marine , López del Amo Juan Miguel , Lian Jian Xiang , Bonilla Francisco , Carrasco Javier , Armand Michel , Rojo Teófilo , Casas-Cabanas Montse
Published: May 2020

Polyanionic compounds stand out as attractive candidates for electrode materials in Na-ion and Li-ion batteries due to their stable 3D framework.1 Furthermore, according to theoretical calculations, N-substituted polyanionic compounds should enable the use of more than one redox couple of transition metals due to the lowering their working voltage.2

Nitridophosphates, with general formula NaxMy(PO3)3N, exhibit an open 3D structure that facilitates the migration of ions at room temperature and enables stable cycling.3,4 In particular, our research has uncovered the remarkably high working voltage of Na3V(PO3)3N (4.0 V vs Na+/Na0 , Figure 1) which, together with Na7V3(P2O7)4, is the highest operating voltage for Na-ion cathode material for the VIV+/VIII+ redox couple.5,6 Moreover, Na3V(PO3)3N can also be used as a cathode in a hybrid Lithium-ion configuration.

The Li counterpart Li3V(PO3)3N, can be prepared by chemical ion exchange. Its 6Li ssNMR spectrum exhibits three different peaks that have been assigned to the three independent Li sites and the Li mobility between those sites was probed by 2D exchange spectroscopy (EXSY), as shown in Figure 1c.

Aiming to lower the cost and improve the electrochemistry we have further explored the family of nitridophosphates. Seeking for redox-active transition metal we focused on economical and earth abundant 3d metals. Our studies resulted with improving the electrochemical performance of Na2Fe2(PO3)3N vs Na and synthesizing for the first time cobalt nitridophosphate, Na2Co2(PO3)3N with expected electrochemical activity at ~4.5V vs Na+/Na0. Endeavoring to obtain a manganese nitridophosphate we have discovered a new family of compounds which will be also shown.7

1. C. Masquelier and L. Croguennec, Chem. Rev. 113, 6552 (2013).

2. M. Armand and M.E.A. y de Dompablo, J. Mater. Chem. 21, 10026 (2011).

3. J. Liu, X. Yu, E. Hu, K.-W. Nam, X.-Q. Yang, and P.G. Khalifah, Chem. Mater. 25, 3929 (2013).

4. J. Liu, D. Chang, P. Whitfield, Y. Janssen, X. Yu, Y. Zhou, J. Bai, J. Ko, K.-W. Nam, L. Wu, Y. Zhu, M. Feygenson, G. Amatucci, A. Van der Ven, X.-Q. Yang, and P. Khalifah, Chem. Mater. 26, 3295 (2014).

5. M. Reynaud, A. Wizner, N. A. Katcho, L.C. Loaiza, M. Galceran, J. Carrasco, T. Rojo, M. Armand, and M. Casas-Cabanas, Electrochemistry Communications 84, 14 (2017).

6. C. Deng, S. Zhang, and B. Zhao, Energy Storage Materials 4, 71 (2016).

7. A. Wizner, M. Reynaud, J.X. Lian, F. Bonilla, J.-M. Lopez del Amo, J. Carrasco, T. Rojo, M. Armand and M. Casas-Cabanas, submitted.

Figure 1
Carbon-Coated Aluminium Current Collectors for New Li-Ion Battery Generation
Authors: Bizot Chloé , Blin Marie-Anne , Guichard Pierre , Soudan Patrick , Lestriez Bernard , Gaubicher Joël , Poizot Philippe
Published: May 2020

Since 2015, ARMOR has been designing and producing coated current collectors for lithium-ion batteries and super-capacitors. The En’Safe® technology (represented in Figure 1) uses a thin conductive coating made of carbon and polymer deposited on a metallic substrate. The presence of this thin layer results in lower contact resistance and improved adhesion between the substrate and the electrode which ultimately allows for improved power performances and better cyclability of these energy storage systems (1).

At the industrial scale, the deployment of high-voltage positive material (such as LiNi0,5Mn1,5O4) for new Li-ion battery generation is still facing many issues. Indeed, the different cell components of the positive side can suffer from degradation when polarized at high voltage and high performances are still not achieved. According to our extended investigation, the use of imide-based lithium supporting salts (LiTFSI or LiFSI) is very promising for next generation battery as it is much safer than LiPF6 and enable to stabilize the positive electrode/electrolyte interface, However, traditional aluminium current collector suffers from severe oxidation from 3.7 V vs. Li+/Li in such media.

In this contribution, we will present the new challenges facing ARMOR coated current collectors for next generation lithium-ion batteries with special emphasis on aluminium stability when polarized at high voltage in Al3+-complexing electrolyte media. We will show that the ARMOR coating effectively suppresses aluminium oxidation without any additive or change in solvent. In addition, we are also developing novel aluminium coatings stable enough up to 5 V vs. Li+/Li in order to ensure a high electronic conduction and a long time life of the positive current collector.

(1) C. Busson et al., Journal of Power Sources 406 (2018) 7.

Figure 1
Electrolyte, Solvation Shell and Interphase for Ca and Mg Metal Anode Based Batteries
Authors: Forero-Saboya Juan , Ponrouch Alexandre
Published: May 2020

Various metals have been used as battery anodes in electrochemical cells ever since the birth of the batteries with Volta’s pile and in the first commercialized primary (Zn/MnO2, Leclanché 1866) and secondary (Pb/acid, Planté 1859) batteries. Li-MoS2 cells, employing Li metal anodes, with specific energies two to three times higher than both Ni/Cd and Pb/acid cells, were withdrawn from the market due to safety issues related to dendrites growth. Instead, electrodeposition of Mg and Ca appears to be less prone to dendrite formation.[1,2] Pioneering work by Aurbach et al. in the early 1990’s showed a surface-film controlled electrochemical behavior of Ca and Mg metal anodes in electrolytes with conventional organic solvents.[3,4] The lack of metal plating was attributed to the poor divalent cation migration through the passivation layer.

Nevertheless, recent demonstration of Ca and Mg plating and stripping in the presence of a passivation layer or an artificial interphase [2,5,6] has paved the way for assessment of new electrolyte formulations with high resilience towards oxidation. However, several challenges remain to be tackled for the development of Ca and Mg based batteries.[7,8] Among these, the need for reliable electrochemical test protocols, mass transport limitations and high desolvation energies (due to strong cation-solvent and cation–anion interactions) are implied.[9, 10] Here, the reliability of electrochemical set-ups involving multivalent chemistries is discussed, and a systematic investigation on the impact of the electrolyte formulation on the cation solvation structure and transport is presented.

References

1. M. Matsui, J. Power Sources, 196 (2011) 7048.

2. A. Ponrouch, C. Frontera, F. Bardé, M.R. Palacín, Nat. Mater., 15 (2016) 169.

3. D. Aurbach, R. Skaletsky, Y. Gofer, J. Electrochem. Soc.138 (1991) 3536.

4. Z. Lu, A. Schechter, M. Moshkovich, D. Aurbach, J. Electroanal. Chem. 466 (1999) 203.

5. D. Wang, X. Gao, Y. Chen, L. Jin, C. Kuss, P. G. Bruce, Nat. Mater. 17 (2018) 16.

6. S.-B. Son, T. Gao, S. P. Harvey, K. X. Steirer, A. Stokes, A. Norman, C. Wang, A. Cresce, K. Xu, C. Ban, Nat. Chem. 10 (2018) 532.

7. A. Ponrouch, M.R. Palacín, Current Opinion in Electrochemistry 9 (2018) 1.

8. A. Ponrouch, J. Bitenc, R. Dominko, N. Lindahl, P. Johansson, M.R. Palacin, Energy Storage Materials 20 (2019) 253.

9. D. S. Tchitchekova, D. Monti, P. Johansson, F. Bardé, A. Randon-Vitanova, M. R. Palacı́n, A. Ponrouch, J. Electrochem. Soc., 164 (2017) A1384.

10. J. D. Forero-Saboya, E. Marchante, R. B. Araujo, D. Monti, P. Johansson, A. Ponrouch, J. Phys. Chem. C (2019).
A Rapid Deposition of Lithium Cobalt Oxide Thin Film As Cathode By Atmospheric Plasma Spraying Method
Authors: Wu Bo-Hsien , Tsai Chun-Huang , Hsueh Tien-Hsiang , Chang Chun-Liang , Wang Min-Chuan
Published: May 2020

Lithium ion batteries (LIB) have been widely-applied for decades. For safety concerns, all parts of the batteries especially electrolyte tend to be solid state rather liquid state. This research was conducted by assembling all-solid-state batteries (ASSB). Cathode, LiCoO2 (LCO), was fast deposited by atmospheric plasma spraying (APS) method on stainless steel. The cathode film could be rapidly formed in few minutes and the thickness of LCO would reach to 10~40 μm. After heat treatment for few hours, the roughness of the cathode film was still high and could not be eliminated. High roughness of the cathode would reduce the cycle life or fail the battery. In order to assure that the batteries could work properly with reliable capacity, smoother surface of LCO thin films would be required. Hence, aerosol deposition (AD) method was conducted after APS method to solve this issue. By AD, surface-modified LCO film was produced and then assembled into ASSB. Owing to AD, the roughness of the LCO thin film could be eliminated significantly to improve the performance of LIB. The electrochemical characterization of ASSB showed the first discharge capacity of 796 μAh and the capacity retention was achieved 100% after 100 charge-discharge cycles between 4.2V and 3V at 0.25C.
High-Capacity Mn-Based Cation-Disordered Rocksalt Cathodes
Authors: Lun Zhengyan , Ouyang Bin , Clément Raphaële J. , Kwon Deok-Hwang , Ceder Gerbrand
Published: May 2020

The discovery of Li-excess cation-disordered rocksalt (DRX) cathodes greatly enlarges the design space beyond the layered NCM-type rocksalt chemistries. More importantly, this new strategy enables high capacity Co and Ni-free cathodes, which is a requirement for the Li-ion industry to grow to the Terra-Wh scale that is needed for the growing electric vehicle and utility applications. Mn-based DRX oxyfluorides are especially promising owing to their large energy densities and good cyclabilities as well as the low cost and earth abundance of Mn.

Herein, we synthesize, characterize, electrochemically test and model four well-chosen compositions within the Li–Mn–O–F DRX chemical space with different Li content and F content: Li1.333Mn(III)0.667O1.333F0.667(HLF67), Li1.333Mn(III)0.5Mn(IV)0.167O1.5F0.5(HLF50), Li1.333Mn(III)0.333Mn(IV)0.333O1.667F0.333(HLF33), and Li1.25Mn(II)0.167Mn(III)0.583O1.333F0.667(LLF67). While all compositions tested achieve higher than 200 mAh/g initial capacity the material with high Li-excess (1.333 per formula unit, Li
x
Mn2-x
O2-y
F
y
) and moderate fluorination (0.333 per formula unit) achieves 349 mAh/g initial capacity and 1068 Wh/kg specific energy. Higher fluorination (0.667 per formula unit) can activate Mn2+/Mn4+redox and thereby balance capacity with cycle life, achieving 256 mAh/g (822 Wh/kg) initial capacity (specific energy) with more than 85% retained after 30 cycles even upon charging to 5.0V. It can be concluded that the Li-site distribution plays a more important role than the metal-redox capacity in determining the initial capacity, whereas the metal-redox capacity is more closely related to the cyclability of the materials. We apply these insights and generate a capacity map of the Li–Mn–O–F chemical space, Li
x
Mn2-x
O2-y
F
y
(1.167 ≤ x ≤ 1.333, 0 ≤ y ≤ 0.667), which predicts both the accessible Li capacity and Mn-redox capacity. This map allows to design compounds which balance high capacity with good cyclability.

Reference

Lun, Zhengyan, et al. "Design principles for high-capacity Mn-based cation-disordered rocksalt cathodes.” Chem (2019), DOI: 10.1016/j.chempr.2019.10.001, in press.
Aluminum Ion Species Transport in Pure and Additive Modulated Deep Eutectic Solvents (DES) Electrolytes
Authors: Suarez Sophia , Paterno Domenec
Published: May 2020

The need for safe, low cost, high energy and density storage devices is ubiquitous the world over. Satisfying this need requires various energy storage and conversion applications, one of which is the aluminum ion batteries. One problem with expansion in their development and commercialization is the availability of optimized electrolytes. Recently, deep eutectic solvents (DES) have gained attention as electrolytes for energy storage devices. These solvents are similar to ionic liquids, but are generally cheaper and easier to prepare. Additionally, they are known to dissolve metal oxides which plague AIBs operation, and their solubility is dependent on the hydrogen bond donor. Because of their inherent tunability, we studied the effect of AlCl3 concentration (1:1 – 1.7:1 molar ratio), amide type (acetamide (AA), butyramide (BA), propionamide (PA)), viscosity reducing additive type and concentration, on the aluminum ion species and transport in AlCl3:amide DES electrolytes using multi-Nuclear (1H, 27Al) Magnetic Resonance (NMR) and AC Impedance Spectroscopy techniques, as a function of temperature. Below are a few noteworthy observations.

Firstly, for both AlCl3:PA and AlCl3:BA DES electrolytes, a maximum in ionic conductivity was observed at the 1.3:1 molar ratio. For AlCl3:AA DES the maximum occurred at the 1.5:1 molar ratio. secondly, the 27Al spectra the 1:1 molar ratio DES electrolytes showed three well resolved peaks at about 101, 88 and 74 ppm, assigned to [AlCl2(amide)2]+, AlCl4
-, and [AlCl2(amide)2]+ respectively. An example of this is shown in Figure 1 for the 1.0:1 (left) AlCl3:PA. With increasing AlCl3 concentration, the narrow well resolved peaks gave way to broadened, asymmetric spectra with two to three visible but not separated peaks. This is also shown in Figure 1 (right) for the 1.3:1 (right) AlCl3:PA. A fourth peak also appeared for DES electrolytes which could be due to free AlCl3:amide species.

Figure 1. 27Al variable temperature spectra for 1.0:1 (left) and 1.3:1 (right) AlCl3:Propionamide (PA).

Thirdly, like the spectra, the 27Al T1 data for the pure DES electrolytes were very dependent on salt concentration and the species type. For the 1:1 molar ratio electrolyte, the AlCl2(amide)+ species had the longest T1, while the AlCl2(amide)2
+had the shortest. Fourthly, with the inclusion of additives such as propylene carbonate (PC) both the 1H and 27Al T1increased, indicating increasing local ion dynamics possibly through the reduction of bulk viscosity effects and Coulombic interactions. In addition to this, PC also caused additional resolution of the [AlCl2(amide)2]+ species - which was not observed in the pure DES. These results and more will be expounded upon in our presentation.

Figure 1