bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrodeposition of Transition Metal Dichalcogenide Thin- Films from Non-Aqueous Solvents
Authors: Thomas Shibin , Greenacre Victoria K , Noori Yasir J , Abdelazim Nema M , Zhang Jiapei , Alodan Sarah A , Ramadan Sami , Bartlett Philip N , Reid Gillian , de Groot C.H. Kees , Klein Norbert 
Published: February 2024

Transition metal dichalcogenides (TMDCs) are an interesting group of 2D materials characterised with a layered structure analogous to graphene and they possess unique electronic and optical properties, especially when in the few- and mono-layer form. Developing scalable techniques for depositing TMDCs is a major challenge which needs to be overcome to fabricate functional devices with these materials. Electrodeposition is an industrially relevant technique that has some key advantages over other conventional deposition methods. It is a low cost and easily scalable technique and could be used for obtaining complex nanoscale features and for depositing over topologically demanding surfaces. Even though the electrodeposition of MoS2 has been achieved both in aqueous and non-aqueous electrolytes, not much progress has been made in the deposition of other TMDC materials. Tungsten based TMDCs such as WS2 and WSe2 are shown to be very promising materials in different applications, however electrodepositing them remains extremely challenging. One of the major obstacles here is developing electrochemically active precursors which are compatible with the electrolyte system and able to deliver both the tungsten and chalcogens to the electrolyte. Controlling and optimizing the deposition process to obtain few- and mono-layer TMDCs is another challenge. In addition, the choice of substrates for deposition is very important, especially for direct growth of ultra-thin TMDCs. Electrodeposition, being a bottom-up deposition method, would benefit from an atomically thin and smooth substrate such as graphene for depositing few- and mono-layer TMDCs.
Here we present non-aqueous electroplating as a scalable alternative technique for tungsten-based TMDC deposition, with WS2 and WSe2 as examples. Tailored single source precursors were developed to use in non-aqueous electrolytes. WS2 was electrodeposited from dichloromethane (CH2Cl2) using the [NEt4]2[WS2Cl4] precursor. WSe2 was then electrodeposited from acetonitrile (CH3CN) electrolyte using [WSeCl4] as the precursor. Electrochemical quartz crystal microbalance (EQCM) studies were performed to optimize the deposition process and to probe the mechanism of precursor electrochemistry. Electrochemical deposition parameters were then carefully adjusted to obtain few- and mono-layer TMDCs. Patterned graphene electrodes were used as an atomically thin and smooth platform for the deposition of few- and mono-layer WS2. Few-layer TMDC films obtained on graphene were found to be much smoother than films deposited on other standard substrates such as titanium nitride (TiN) or Pt. These TMDC/graphene structures gave interesting 2D heterostructures which are technologically important for different applications.
This work was funded by EPSRC grant references EP/V062689/1, EP/V062387/1 and EP/P025137/1
Comparison of Electrochemical Characteristics of in Film on Cu and Ru Surfaces
Authors: La Mai Thi Ngoc , Nakayama Kohei , Inoue Fumihiro 
Published: February 2024

Indium is a potential superconducting interconnect material in a quantum computer, becoming superconducting at 3.37 K [1]. In particular, Indium has good ductility in cryogenic environments, making Indium bonding advantageous for 3D quantum systems. Many researchers have used the ECD method to fabricate Indium micro-bumps because of the requirement of low temperature and achieving a high aspect ratio with a high deposition rate. There have been some studies on the formation of micro-bump of Indium on Copper surfaces using the ECD technique, however, Copper is not a superconducting material. Cobalt and Nickel are materials with electromagnetic properties that affect the conductivity of the quantum system. Ruthenium is considered a suitable underlayer for direct deposition owing to its low resistivity (bulk resistivity of 7.1 μΩ.cm) [2, 3] and transition temperature of 0.47 K [4]. To the best of our knowledge, the deposition of an In film on the Ru surface has not been studied. Therefore, this study aims to evaluate the formation of In thin films on the Ru surface as well as compare the characteristics of In on Cu and Ru surfaces to develop the superconducting Indium micro-bump technology.
Indium deposition was studied in a standard three-electrode cell using a potentiostat-galvanostat system. Before deposition, the ruthenium surface was cleaned for 180s at a fixed current of -10 mA/cm2 in 1.2 mol/L H2SO4 [5]. The primary electrolyte was an indium solution (MicroFAB In4950) with an additive (MicroFAB Uniformer).
In Fig. 1, the electrochemical behavior of In solution on Cu and Ru surfaces was investigated. Indium metal begins to deposit at -0.87 V and dissolve at -0.25 V on the Cu surface. Meanwhile, the peak currents of In on the Ru surface at the cathode and anode are -1.75 V and 1.17 V, respectively. The electrochemical reaction of Indium is on Cu and Ru surfaces by the following reaction (1):
In3+ + 3e- ↔ In (1)
SEM micrographs observations of both surfaces at each stage show that island growth occurs when the potential is applied, specifically that the nanoparticles coated on the Ru surface have a porous morphology. The formation of the porous structure upon increasing the voltage on the Ru surface is due to the generation of H2 bubbles, so this study further clarifies the mechanism of In film formation on the Ru substrate. In addition, the change in current is evaluated to determine the effect of current on the structure of the In film. The roughness, thickness, and crystal structure of In film layer have all been thoroughly investigated. To evaluate the bonding ability in low temperatures, the micro-bump formation on both Cu and Ru substrates is demonstrated.
In conclusion, the properties and deposition mechanism of In films on Cu and Ru are investigated using the ECD technique. The surface properties of Ru influenced nucleation and In film properties, suggesting a potential study to elucidate the mechanism of In deposition on Ru.

Figure 1
Influence of Process Conditions during Aqueous and Direct Recycling of NMC811 Cathodes
Authors: Nagler Felix , Christian Nino , Kolb Leonhard , Flegler Andreas , Hofmann Michael , Giffin Guinevere A. 
Published: February 2024

A binder-solvent system consisting of polyvinylidene fluoride (PVDF) and N-methyl-2-pyrrolidone (NMP) is commonly used in state-of-the-art cathodes for lithium-ion batteries [1]. However, NMP is highly toxic and requires energy-intensive production processes as well as solvent recovery and purification systems to prevent uncontrolled evaporation [2]. To reduce the cost and environmental impact of cathode production, carboxymethyl cellulose (CMC) and water can be used as an alternative to PVDF and NMP [3]. In addition, the use of water instead of organic solvents for binder deactivation in aqueous processed cathodes would make direct recycling much more attractive.
This study investigates the process conditions for direct recycling of aqueous processed NMC811 cathodes by varying parameters such as the amount of water, process time, and pH of the water bath. The recycled NMC materials are characterized by various techniques, including thermogravimetric and mass spectrometry (TG-MS), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements such as EIS and galvanostatic cycling.
The results show that the ratio of water to NMC has a significant effect on the amount and type of surface species formed on the NMC811 surface. The ratio of NMC811 to water was varied between 1:1 and 1:50, representing possible water concentrations in the direct recycling process. The formation of surface species directly affects the electrochemical performance. Higher water concentrations were associated with higher charge transfer resistances and lower discharge capacities. TG-MS and XPS measurements identified the additional species as the cause. These were mainly transition metal carbonates and hydroxides.
In addition, by adding aluminum foil to the water-NMC mixture, the process conditions during the current collector detachment step within direct recycling are investigated. In the aqueous medium, the high pH of about 11.5 leads to the formation of aluminum-containing species due to aluminum corrosion. These species form a surface layer on the NMC particles, which limits the amount of Li leached, but also induces higher polarization. When aluminum corrosion is prevented by adding acid to regulate the pH, the material leaches more Li but also has less polarization. Overall, the importance of controlling the process conditions during aqueous and direct recycling is demonstrated.
References
[1] F. Font, B. Protas, G. Richardson, and J.M. Foster. Journal of Power Sources, 393:177–185, jul 2018.
[2] R. Borah, F.R. Hughson, J. Johnston, and T. Nann. Materials Today Advances, 6:100046, jun 2020.
[3] David L. Wood, Jeffrey D. Quass, Jianlin Li, Shabbir Ahmed, David Ventola, and Claus Daniel. Drying Technology, 36(2):234–244, aug 2017.

Figure 1
On the Description of Electrode Materials Based on the Quantification of Ionic and Electronic Work Functions
Authors: Weitzel Karl-Michael , Schepp Johanna , Schuch Jona , Hofmann Jan Philipp , Adams Stefan 
Published: February 2024

During decharging of a lithium ion battery (LIB) electrons are transferred from the cathode material to the outer circuit and lithium ions are transferred into the electrolyte. Here, the energy required to take electrons and lithium ions out of two prototypical cathode materials, LixFePO4 and LixMn2O4 is investigated as a function of the state of lithiation, x [1]. Ionic work functions are measured by thermionic emission, electronic work functions are measured either by thermionic emission or by photoelectron spectroscopy. The work functions measured vary significantly with x for LixFePO4 with moderate, low-dimensional ionic and electronic conductivities but rather little for cubic LixMn2O4 with ca. three orders of magnitude higher ionic and electronic conductivities [2]. The experimental data are supported and rationalized by static energy-landscape calculations and molecular dynamics simulations of the Lithium migration as a function of Lithium content and electric field strength [1]. This study provides new insight into the role of ionic contributions to the energy balance in LIBs. Current efforts are aimed at a complete energetic description of LIBs as previously discussed for LiCoO2 [3].
[1] J. Schepp, J. Schuch, J.P. Hofmann, S. Adams, K.-M. Weitzel, to be published
[2] M. Park, X. Zhang, M. Chung, G.B. Less, A.M. Sastry, A review of conduction phenomena in Li-ion batteries, Journal of Power Sources 195 (2010) 7904–7929.
[3] S. Schuld, R. Hausbrand, M. Fingerle, W. Jaegermann, K.-M. Weitzel, Experimental Studies on Work Functions of Li+ Ions and Electrons in the Battery Electrode Material LiCoO2 A Thermodynamic Cycle Combining Ionic and Electronic Structure, Adv. Energy Mater. 8 (2018) 1703411.
Analysis of Electrode Materials for Li-Ion Batteries by Synchrotron Soft X-Ray Microspectroscopy
Authors: Hosono Eiji , Asakura Daisuke , Zhang Wenxiong , Yuzawa Hayato , Kobayashi Masaki , Nagamura Naoka , Tanaka Shingo , Miyawaki Jun , Kiuchi Hisao , Ohigashi Takuji , Oshima Masaharu , Harada Yoshihisa 
Published: February 2024

The development of clean energy devices such as Li-ion batteries is attracting attention in order to realize a low-carbon society. In addition to development of materials for Li-ion batteries, advanced analytical methods are also being developed to obtain the guideline of new materials and improve battery performance. We have been working on electronic structure analysis of transition metals and oxygen using synchrotron soft X-ray absorption and emission spectroscopy including ex-situ measurements and operando measurements. [1-3] We have also reported on synchrotron radiation micro-photoemission spectroscopy of all-solid-state Li-ion batteries using an operando measurement system. [4,5]
In this presentation, we report analysis of each facet of a single crystalline LiCoO2 particle by resonant photoemission microspectroscopy. Resonant photoemission spectroscopy is element-selective method for obtaining valence band spectra using excitation energies around the absorption edge of target elements. Co 2p-3d absorption (L
2,3 absorption edge) of LiCoO2 was used to study the Co 3d orbitals near the Fermi level in detail. [6] Next, we report on the absorption spectroscopy of LiCoO2 using scanning transmission X-ray microscopy (STXM). The spatial resolution of about 100 nm can be used to analyze the chemical state distribution for each particle or within each particle. [7]
References

Electrochem. Commun. 50 (2015) 93-96.

Phys. Chem. Chem. Phys. 21 (2019) 26351–26357.

Phys. Chem. Chem. Phys. 24 (2022) 19177-19183.

J. Electron Spectrsc. Relat. Phenom., 233 (2019) 64-68.

Sci. Rep., 9 (2019) 12452.

CrystEngComm, 25 (2023)183-188.

Sci. Rep., 13 (2023) 4639.
(Invited) Atomic Scale Details in Electrochemistry & Electrodeposition: The Good, the Bad, and the Ugly
Authors: Rost Marcel J. 
Published: February 2024

Since the invention of the STM more than 40 years ago, which enabled the direct observation of surfaces on the atomic scale, it took us around 25 years full of surprises, before we gathered enough knowledge to formulate a decent background including almost all surface science phenomena [1].
At this time, it was often believed that fundamental surface science was dead. However,
progress in nanotechnology and the semiconducting industry, kept this discipline alive, although the number of researchers steadily decreased. Being at the border between physics and chemistry, electrochemistry and electrodeposition research was executed on the atomic, fundamental level by only a few “Mohicans”.
The Good is:
- that the required energy transition makes our discipline increasingly relevant.
- that this leads to a revival of surface science.
- that more and more researchers from different fields step into our business.
- that we developed in operando methods, like ECSTM, SXRD, and XPS, that deliver atomic insights.
- that inventive new methods become available, like the reaction volume or entropy on the atomic scale.
- that our complex machines get easier over time.
- that we constantly gain new fundamental, atomic scale insights.
The Bad, however, is:
- that the combination of electrochemistry with surface science is a real complex matter.
- that the parameter space in electrochemistry is orders of magnitudes larger than surface science.
- that there are too less groups and researchers, in general, to tackle all emerging problems.
- that the time is ticking: global climate change is not waiting to figure out all details.
- that we will need at least one generation to educate new students.
The Ugly is severe, interesting and challenging, as it becomes clear:
- that, instead of directly gaining more insights, often a multitude of additional questions emerge.
- that there is a complex interplay of fundamental atomic and molecular processes.
- that “known” textbook knowledge should be taken with a grain of salt.
- that some fundamentals are even missing completely: our research is still in its infancy.
- that there exists an enormous amount of literature describing a magnitude of different effects.
- that one needs expertise of several different fields to really understand one detail.
In my talk, I will present several recent examples, in which we thought that we had understood it. Often one last, small experiment was required to deliver the final confirmation. Oh boy, and how often have we been wrong. Nature confronts us with what we do not know! It will be a long and arduous journey, but similar to the early days in surface science, full with exciting and surprising puzzles from nature.
I hope that I can trigger your enthusiasm to join our important journey!
[1] H. Ibach, “Physics of Surfaces and Interfaces”, Springer (2006)
(Invited) Confined Electrodeposition Enables Additive Manufacturing of Metals at Micro- and Nanoscale
Authors: Momotenko Dmitry 
Published: February 2024

Additive manufacturing, also commonly known as 3D printing, is rapidly becoming a part of our everyday life: from DIY use by hobbyists to industrial manufacturing, 3D printing is experiencing a booming success. The technologies advance quickly with faster print rates, broader choice of materials and a constantly increasing accuracy and printing resolution. Impressively, state-of-the-art techniques take the printed feature sizes to the extreme: multiphoton optical stereolithography and focused electron or ion beams are now capable to produce objects with nanoscale resolution. Although at the cutting edge to printing finest details, these advanced manufacturing methods lack the capacity to process dense and pure electrical conductors – materials very much needed to push the limits of the technologies of the future – sensors, energy storage devices, logical gates and memory interfaces.
Electrochemical methods, which have an advantage to process a wider range of materials – conductors and semiconductors, bulk materials and colloids, at a first glance, have little to do with additive manufacturing. Electrodeposition, a well-established approach traditionally used to produce metallic coatings or thin films, is often integrated in microfabrication process but is limited to planar two-dimensional designs. However, when combined with state-of-the-art nanoelectrochemical approaches, electrodeposition can be taken into a three-dimensional realm, where it can be used to produce complex structures with micro- and nanoscale dimensions [1]. The key to achieve this is nanoscale confinement of precursor delivery that is combined with layer-by-layer additive processing. Liquid manipulation by pressure driven flow through nanoscale cantilevers [2] or intermittent meniscus formation using droplet cells [3] – a variety of nanoelectrochemical techniques can be used to fabricate metallic structures with various morphologies. The recent advances in these technologies including instrumental aspects, performance metrics such as resolution and print rates, as well as some materials characteristics are highlighted in this talk.

References

[1] J. Hengsteler, G. P. S. Lau, T. Zambelli, D. Momotenko, „Electrochemical 3D Micro- and Nanoprinting: Current State and Future Perspective.“ Electrochem.
Sci. Adv., 2:e2100123 (2023).
[2] G. Ercolano, C. van Nisselroy, T. Merle, J. Vörös, D. Momotenko, W. W. Koelmans, T. Zambelli, „Additive Manufacturing of Sub-Micron to Sub-mm Metal Structures with Hollow AFM Cantilevers.“ Micromachines,
11, 6 (2020)
[3] J. Hengsteler, B. Mandal, C. van Nisselroy, G. P. S. Lau, T. Schlotter, T. Zambelli, D. Momotenko, „Bringing Electrochemical Three-Dimensional Printing tot he Nanoscale.“ Nano Lett.,
21, 9093 (2021).
Co-Sintering of Lithium Aluminum Germanium Phosphate (LAGP) Glass/Powder Composite Electrolyte for Multilayer Ceramic Batteries
Authors: Park Young Ji , Kang Taewook , Kim Sun Woog 
Published: February 2024

Inorganic solid electrolytes are one of the key materials instead of organic liquid electrolytes for next-generation all-solid-state batteries (ASSBs). The advantages of ASSBs are long cycle life and high safety due to the non-flammable of the solid electrolyte. The ASSBs can be stacked layer by layer, reducing the volume in battery packaging and resulting in increased energy density. These ASSBs can be applied to wearable or healthcare or smart home devices in the form of multilayer ceramic battery (MLCB), in addition to energy storage devices and electric vehicles. However, the MLCBs are difficult to fabricate due to the high sintering temperature and high interfacial resistance of the solid electrolyte. The Li-based solid electrolytes of NASICON-type have received much attention as prospective solid electrolytes due to their high ionic conductivity and high stability against moisture. Especially, lithium aluminum germanium phosphate (LAGP) is potential solid electrolyte material in the NASICON family due to superior stability. LAGP glass electrolyte was selected to enable sintering at low temperatures and reduce resistance at the interface for the application to MLCB.
In this study, a LAGP-based solid electrolyte ceramic sheet was prepared using glass/powder composite at 750 °C. The obtained LAGP-based solid electrolyte exhibited a NASICON-type hexagonal structure and a total ionic conductivity of 1.45 × 10-4 S/cm at 25 ˚C. A Coin cell with the LAGP composite electrolyte, LiCoO2 (LCO) as cathode, and Li metal as anode was assembled. The coin cell was charged and discharged by using a battery cycler and the charge capacity was approximately 130 mAh∙g-1. Additionally, we prepared a LiMnPO4 glass-based cathode (LMP) using conventional melt quenching techniques and then stacked it layer by layer with the LAGP electrolyte and co-sintered at 650°C. After co-sintering the LAGP/LMP cell, it was confirmed that the interface between the LAGP composite electrolyte and the LMP cathode was well attached, and its ionic conductivity maintained a value similar to that of the LAGP composite electrolyte. Subsequently, an electrochemical analysis of the LAGP/LMP cell was performed.
Multiple Diffusion Processes in Lithium-Ion Battery Electrolytes
Authors: Lehnert Lukas , Latz Arnulf , Wagner Norbert , Nojabaee Maryam , Horstmann Birger 
Published: February 2024

Numerical simulations are a powerful tool for the development and improvement of Li-ion batteries[1]. Modelling the mass transport of the involved electrolytic solutions requires precise determination of the corresponding electrolyte parameter. However, the determination methods are still controversially discussed.
In this work, we attempt to measure the complete set of electrolyte parameter for a system of 0.5 M LiPF6 dissolved in a blend of ethylene carbonate and ethyl methyl carbonate (EC:EMC, 3:7 weight) at 20°C and 50°C. In order to determine the conductivity, the diffusion coefficient, the transference number and the thermodynamic factor we conduct a combination of concentration cell measurements, galvanostatic polarization experiments and electrochemical impedance spectroscopy[2].
While the conductivity and concentration cell measurements show comparable results to the literature, we find the potential response in the polarization experiments deviating from theoretical expectations. Applying galvanostatic polarization experiments to symmetrical metal Li | electrolyte + separator | Li metal cells result in slower, impeded diffusion processes. This indicates the presence of additional, undesired porous structures on the Li electrodes, preventing a reliable evaluation of the electrolyte parameters[3]. To spectrally resolve the diffusive processes, we conduct very low frequency impedance spectroscopy in an attempt to identify the impedance for the sole diffusion through the separator[4].
1. Max Schammer et al 2021 J. Electrochem. Soc. 168 026511
2. Johannes Landesfeind and Hubert A. Gasteiger 2019 J. Electrochem. Soc. 166 A3079
3. Talian et al. The Journal of Physical Chemistry C 2019 123 (46), 27997-28007
4. F. Wohde et al 2016 J. Electrochem. Soc. 163 A714
Figure 1: VLF-IS measurements with amplitudes of 60µA, 500µA and 10µA together wit the corresponding equivalent circuits, fits and Kramers-Kronig transformations at 20° C and 50°C respectively

Figure 1