bluuebunny/crossref_metadata_2025 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
Electrochemical Synthesis of Core-Shell Nanoparticles by Seed-Mediated Selective Deposition
Authors: Park Joon Ho , Ahn Hyun
Published: February 2024

Conventional solvothermal synthesis of core–shell nanoparticles results in them being covered with surfactant molecules for size control and stabilization, undermining their practicality as electrocatalysts. Here, we report an electrochemical method for the synthesis of core–shell nanoparticles directly on electrodes, free of surfactants. By implementation of selective electrodeposition on gold cores, 1st-row transition metal shells were constructed with facile and precise thickness control. This type of metal-on-metal core–shell synthesis by purely electrochemical means is the first of its kind. The applicability of the nanoparticle decorated electrodes was demonstrated by alkaline oxygen evolution catalysis, during which the Au–Ni example displayed stable catalysis with low overpotential.
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.
Anionic Effects on Li-Ion Activity and Intercalation Kinetics in Highly Concentrated Electrolytes
Authors: Dokko Kaoru , Ugata Yosuke , Ueno Kazuhide , Watanabe Masayoshi
Published: February 2024

Certain highly concentrated electrolytes (HCEs) enhance the charge-transfer reaction rate at the electrode/electrolyte interface in Li-ion batteries. The solvation structure of Li+ in HCEs significantly affects the electrochemical interfacial reaction kinetics.1 However, the effects of different anions on these kinetics have not yet been fully understood. In this study, we investigated the effects of anionic species on the liquid structure and electrochemical reactions of HCEs composed of various Li salts and propylene carbonate (PC).2 Raman spectra revealed that both PC and anions were coordinated to Li+ ions in HCEs and that the concentration of uncoordinated (free) PC changed depending on the anionic species. Consequently, the activity of Li+ in the electrolyte changed depending on the anionic species. The use of Li salts with weakly Lewis basic anions increased the activity of Li+ and decreased the concentration of free PC in HCEs.The activity of Li+ in the electrolyte significantly affected the Li+ intercalation/deintercalation reaction rate of the LiCoO2 thin-film electrode. Electrochemical impedance spectroscopy revealed that the interfacial reaction rate of LiCoO2 was enhanced in the HCEs with anions having weaker Lewis basicity owing to the higher Li+ ion activity. In addition to the Li+ ion activity, the electrolyte viscosity also gives a significant effect on the charge-transfer kinetics at the electrode/electrolyte interface. The effects of salt concentration and anionic species on Li+ ion activity, electrolyte viscosity, and reaction kinetics in the HCEs will be discussed in detail.

Acknowledgements
: This study was partially supported by the JSPS KAKENHI (Grant No. JP19H05813, JP21H04697, and JP22H00340).

References

Y. Kondo et al., ACS Appl. Mater. Interfaces 2022, 14, 22706-22718.

Y. Ugata et. al., J. Phys. Chem. C 2023, 127, 3977-3987.
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).
Electrochemical Performances Ti4Ti5O12/Si Composite Anodes for Li-Ion Batteries
Authors: Merazga Saloua , Boudeffar Fatima , Achouak Bouaoua , Larabi Amina , Mebarki Mourad , Berouaken Malika , Gabouze Noureddine
Published: February 2024

LTO /Si anode material for lithium-ion batteries were successfully synthesized by two-step hydrothermal method and ball milling synthesis , using tetrabutyl titanate, lithium acetate,silicone powder. In this work, LTO/Si composites with different weight ratios (50%,70%) were prepared and tested as anodes of Li-Ion Batteries.The electrochemical properties of the electrodes were investigated using by cyclic voltammetry , charge-discharge galvanostatic and impedance spectroscopy .Both the anodic and cathodic peaks from LTO and silicon were seen in the composites.LTO/SI Composites with higher Si contents (LTO =30 %et Si = 70%) have higher specific capacity .the results confirme that This material can be used as a high-power anode material in lithium-ion batteries.
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
Lithium-Ion Batteries Enhancing Cycling Performance of Silicon Graphite Anodes Using Carbon Nanotubes
Authors: Kinyanjui Francis , Hakim Charifa
Published: February 2024

Silicon graphite anodes have emerged as promising candidates to replace conventional graphite anodes due to their higher theoretical capacity and ability to store more lithium ions. However, the significant volume expansion of silicon during lithiation and delithiation cycles results in severe mechanical degradation and rapid capacity fade, limiting their practical application. Additionally, the realisation of electrodes with high Si content are further limited by poor diffusion kinetics, resulting in an insufficient rate capability performance and lithium trapping.

In this study carbon nanotubes (CNTs) are incorporated into the silicon graphite anode matrix as a strategy to mitigate these issues and enhance the cycling performance of LIBs. The CNTs, with their unique mechanical, electrical, and chemical properties, offer numerous benefits, including enhanced structural integrity, improved electrical conductivity, and increased lithium-ion diffusion kinetics. We investigated the effect of different ratios of CNTs on the cycling performance of silicon graphite anodes. The electrochemical performance of the composite electrodes were systematically evaluated using galvanostatic cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Preliminary results show that the addition of CNTs to silicon graphite anodes significantly improves their cycling stability and rate capability. The composites exhibit reduced capacity fade, improved coulombic efficiency, and enhanced rate performance compared to silicon graphite anodes absent of the CNTs, facilitated by faster lithium-ion diffusion kinetics, leading to improved electrochemical performance.
A Step Towards the Impossible – the Combination of High Ionic Conductivity and Mechanical Stability in Highly Crystalline Solid Polyketone Electrolytes
Authors: Andersson Rassmus , Johansson Isabell Lee , Hernández Guiomar , Mindemark Jonas
Published: February 2024

Implementation of solid polymer electrolytes (SPEs) is believed to be one pathway forward in the development of lithium-metal batteries (LMBs) that are both safe and possesses high capacities. This combination is possible since the free-standing SPE maintains its mechanical integrity during electrochemical and thermal exposure while utilizing lithium metal as the negative electrode, thus accessing the extremely high theoretical capacity of lithium metal. The main drawback for SPEs are however the poor ionic conductivity compared to the liquid electrolytes used in lithium-ion batteries today.[1] The low ionic conductivity for SPEs stems from the conduction mechanism of the ions, which is a slower process in SPEs compared to in liquid electrolytes. In general, the conductivity in SPEs are confined to the amorphous regions, where segmental motion of the polymer chains facilitates the ion transport; while the crystalline regions restrict the movements of the polymer chains and impairs the ion transport.[2]

The highly crystalline polyketone poly(1-oxoheptamethylene) (POHM) is a material that has shown interesting characteristics for implementation as a SPE in batteries. In earlier studies, the polyketone revealed an extensive improvement of the ionic conductivity upon increasing the salt concentration, although the crystallinity remained with a high melting point.[3]

Herein this study, the effect of the crystallinity on the characteristics and the performance was investigated further. To understand its effect, a second less hydrogenated version of POHM was synthesized, POHM-75, which is fully amorphous at high salt concentrations. The characteristics of the polyketones were in addition also compared with the more well-studied SPEs, that is polyethylene oxide (PEO) and poly(trimethylene carbonate) (PTMC). Focus of the presentation is on the interplay between the ionic conductivity and mechanical stability for the polyketones, for which something different to the normally observed tradeoff between the two properties is observed. The electrochemical performance of the polyketones are furthermore evaluated when implemented as SPEs in LMBs at extreme temperature environments, a possible application area for mechanically stable SPEs.

[1] D. Zhou, D. Shanmukaraj, A. Tkacheva, M. Armand, G. Wang, Chem
2019, 5, 2326-2352.

[2] M. A. Ratner, P. Johansson, D. F. Shriver, MRS Bulletin
2011, 25, 31-37.

[3] T. Eriksson, H. Gudla, Y. Manabe, T. Yoneda, D. Friesen, C. Zhang, Y. Inokuma, D. Brandell, J. Mindemark, Macromolecules
2022, 55, 10940-10949.

Figure 1
Revisiting the Anodic Stability of Aluminum Current Collectors in High-Voltage Li-Ion Batteries
Authors: Etman Ahmed S. , Nyholm Leif
Published: February 2024

High-voltage Li-ion batteries are anticipated to play a crucial role in the present transition towards electric vehicles, owing to their high energy density. However, a big challenge is the anodic stability (often referred to as corrosion) of the positive electrodes current collector, aluminum (Al), at potentials > 3.0 V vs. Li+/Li). In this work, we present a systematic study on the corrosion of 12 µm-thick Al foil (©Gränges, Sweden) up to 5.0 V vs. Li+/Li in a series of carbonate electrolytes containing lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl) imide (LiFSI) or lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salts. The selection of the 12 µm foil was motivated by the need to decrease the mass or volume of the dead weight components (i.e., current collector) to increase the energy density of the battery.

The electrochemical behavior was investigated using voltammetric techniques, and the results indicated that the anodic oxidation of the 12 µm Al foil was similar to that of the conventionally used 20 µm-thick Al foil. Notably, the first anodic oxidation scan exhibited a two-step oxidation after 3.5 V vs. Li+/Li, suggesting carbonate solvent oxidation and a liberation of H+ ions attacking the native surface Al2O3 layer followed by oxidation of metallic Al. A passivation was observed on the subsequent scans in 1.0 M LiPF6 solutions due to formation of surface layer of AlF3, as confirmed by X-ray photoelectron spectroscopy (XPS) analyses. [1,2]

However, in 1.0 M solutions of the imide salts (i.e., LiFSI or LiTFSI) a continuous anodic oxidation of aluminum was seen between 3.5 and 5.0 V vs. Li+/Li on the first few scans. After this the magnitude of the anodic current decreased significantly. The latter observations can be attributed to formation of soluble Al(TFSI)
x
or Al(FSI)
x
complexes [3] and a gradual saturation of the electrolyte. The voltammetric experiments showed that the magnitude of the anodic current increased when increasing the volume of the used imide electrolyte, supporting the saturation hypothesis.

Results and analyses regarding the anodic oxidation of Al in a series of carbonate solvents and using different salt concentration, as well as effect of the use of carbon coated Al will also be presented.

References:

[1] S. T. Myung, Y. Sasaki, S. Sakurada, Y. K. Sun, H. Yashiro, Electrochim. Acta
2009, 55, 288.

[2] C. Bizot, M.-A. Blin, P. Guichard, J. Hamon, V. Fernandez, P. Soudan, J. Gaubicher, P. Poizot, Electrochem. commun.
2021, 126, 107013.

[3] M. Morita, T. Shibata, N. Yoshimoto, M. Ishikawa, J. Power Sources
2003, 119–121, 784.
Understanding Lithium-Ion Battery Degradation through P2D Model Parameters Evolution
Authors: Sordi Gabriele , Rabissi Claudio , Casalegno Andrea
Published: February 2024

Despite its commercial level, lithium-ion battery ageing is still a hot topic in the research community. Indeed, the relation between ageing and the operating conditions and loads in a real-life operation is under investigation and the corresponding residual life prediction is still a challenging task.

In this work, a combined approach with experiments and modeling is applied. A wide driving cycle campaign is carried out, involving 12 different profiles to test different combinations of temperature, C-rate, SoC and DoD, whose values were defined after a literature review about the most common values in a real application, and highlight their effect on battery ageing. Two calendar ageing campaigns at the same temperatures are also conducted to quantify the acceleration of the degradation rate due to cycling and analyse if the degradation path is different.

For the interpretation of the results, the P2D model is employed. No explicit description of the main degradation mechanisms is applied. Indeed, the degradation is described through the variation of the physical parameters of the usual model implementation, like a reduction of lithium inventory or active electrode material or a variation of reaction rates and diffusion constants. A specific sequence of tests has been developed as check-up procedure. As detailed in 1, it is a trade-off between testing time and the operating conditions that maximise the identifiability of the parameters of the model.

Therefore, the parameter identification problem is performed periodically upon check-ups and parameters trend over time/cycles is derived. Since it is a physical model, every parameter has a physical meaning and its evolution can be associated to a certain range of degradation phenomena. In this way, the model can support the identification of the most likely phenomena that are ongoing in the battery and the value of the parameters constitutes a new concept of state of health, more comprehensive than the residual capacity value.

Finally, the model interpretation is proved in two ways. First, a validation dataset is provided, to evaluate the capabilities of the calibrated model in reproducing the behaviour of an aged cell under different operating conditions with respect to the check-up procedure. Then, some cells undergo post-mortem analyses to verify the origin of degradation and measure the values of the physical parameters, like optical and chemical analyses, q-OCP discharges of harvested electrodes in coin cell setup for thermodynamic parameters or EIS for kinetic parameters.

This approach, though not suitable on-board, provides a novel physics-based method for a reliable analysis of lithium-ion batteries degradation.

1
G. Sordi, C. Rabissi, A. Casalegno, Reliable thermal-physical modeling of lithium-ion batteries: consistency between high-frequency impedance and ion transport. Under Review
(Invited) Electrochemical Deionization for Water Desalination and Direct Lithium Extraction
Authors: Liu Xitong
Published: February 2024

Electrochemical deionization based on carbonaceous and intercalation electrodes has been proposed as a promising candidate for desalinating saline water and for selectively separating toxic or valuable ionic constituents from water. In this talk, I will first introduce our work on the performance evaluation and techno-economic assessment for electrochemical desalination of brackish water. Parametric models were established to estimate the unit cost of water desalination and energy efficiency in electrochemical desalination with different configurations, and results were compared against brackish water reverse osmosis. In the second part of the talk, I will present our work on the development of selective electrochemical separation systems, focusing on the recovery of lithium from water streams. We investigated the selectivity of lithium separation in electrolyte solutions with different cation concentration ratios as well as in simulated brines. Results show that lithium chloride with a purity of >95% can be extracted from high-salinity brines in the presence of competing monovalent and divalent cations.
Organic Faradaic Desalination Cell Based on Polyimide Symmetric Electrodes
Authors: Fombona Pascual Alba , Patil Nagaraj , Garcia - Quismondo Enrique , Goujon Nicolas , Mecerreyes David , Marcilla Rebeca , Palma Jesus , Lado Julio J.
Published: February 2024

Capacitive deionization (CDI) is an energy-efficient and environmentally friendly deionization technology. However, the maximum desalination capacity of conventional carbon-based CDI systems is in the range of 5–25 mg g-1, which compromises the use of this technology in practical applications [1]. Faradaic deionization (FDI) is a promising electrochemical technique, based on storing the ions within the particles/layers of the electrode materials either by intercalation and/or faradic reactions. By this mechanism, FDI has expanded the deionization values above 50 mg g-1. In the last ten years, research on FDI has primarily focused on battery electrode materials, especially in inorganic intercalation compounds, typically used for energy storage [2]. However, inorganic materials have several drawbacks, such as decomposition and dissolution issues, which affect long-term performance along with safety and sustainability aspects and consequently might limit their practical deployment.

As an alternative, we introduce in this work for the first time an all-polymer deionization cell in combination with a rocking-chair desalination (RCD) mechanism with the aim of boosting the deionization performance [3]. A proof-of-concept next generation technology is accomplished by using a redox-active naphthalene-polyimide (poly[N,N′-(ethane-1,2-diyl)-1,4,5,8-naphthalenetetracarboxiimide], named as PNDIE), which is a well conductive and free-standing electrode material, as anode and cathode in a symmetric FDI system. Our approach relies on the synergistic combination of smart redox polymer selection i.e. PNDIE, and the advance configuration of this material into a buckypaper electrode architecture. A detailed electrochemical characterization under various operational conditions in three electrodes standard half-cell and in two electrode coin-cell configurations was performed. The results of those experiments provide critical information to build an all-polymer rocking chair system with practical PNDIE electrodes (92.2 mgPNDIE; 9.6 cm2). This novel FDI lab-cell demonstrated a remarkable desalination capacity (155.4 mg g-1 at 0.01 A g-1) together with a high salt-removal rate and productivity (3.42 mg g-1 min-1 at 0.01 A g-1 and 62 L h-1 m-2, respectively). In addition, long-term stability experiments provided salt adsorption capacity retention values over 95 % after 100 cycles (23 days). Compared to the state-of-the-art deionization technologies (CDI, Hybrid CDI and FDI) the reported technique exhibits superior electrochemical and deionization performance. These results support the idea of using organic materials as a viable alternative for robust and sustainable “water-energy” electrochemical applications.

References:

[1] Y. Lui, ACS Nano, 2021, 15, 13924-13942

[2] Q. Li, Adv. Sci., 2020, 7, 2002213

[3] A. Fombona-Pascual, Chemical Engineering Journal, 2023, 461, 142001

Figure 1
Electrocoagulation Technique for Treating Swine Slaughterhouse Wastewater from Batch to Semicontinuous Operation Mode
Authors: Sandoval Miguel A , Coreño Oscar , García Verónica , Salazar Ricardo
Published: February 2024

In this study, industrial swine slaughterhouse wastewater was treated by electrocoagulation process using batch and semicontinuous operation systems. Electrochemical technique was carried out in batch operation mode during 2.5 h applying different current densities in sulfate and chloride media. After finding the best operating parameters in batch mode (lab-scale), the process was transferred to a semicontinuous pre-pilot scale process using a filter-press FM01-LC type electrochemical reactor fitted with flat plate aluminum electrodes. In this stage, distinct current densities and mean linear flow rates were assessed.

Total organic carbon, chemical oxygen demand, total phosphorus, total nitrogen, and potassium among other parameters were analyzed during both treatments. The industrial swine slaughterhouse wastewater contained TOC 333 mg L–1, COD 1765 mg L–1, TP 13.55 mg L–1, TN 327 mg L–1, K 45 mg L–1, turbidity 102 NTU, color –absorbance 0.90 A.U. at 415 nm–, conductivity 1.9 mS cm–1, and pH 6.9. The highest TOC removal efficiency (72.7%), in semicontinuous process, was found at j = 25 mA cm-2 and ur
= 0.64 cm s-1 with an energy consumption of 19.80 kW h m-3. Residual COD and TP concentrations met the international standard limits. Moreover, complete discoloration and disinfection were achieved. EDXRF, SEM, EDAX, XRD, and FTIR analyzes indicate pollutants were removed by adsorption on aluminum/iron hydroxides/oxyhydroxides.
Electrochemically Induced CO2 Capture Enabled By Aqueous Organic Redox Chemistry
Authors: Jing Yan , Amini Kiana , Xi Dawei , Jin Martin , Alfaraidi Abdulrahman , Gordon Roy G. , Aziz Michael J.
Published: February 2024

Investigations are ongoing to determine whether electrochemically-driven CO2 capture with inexpensive redox-active molecules in aqueous electrolyte in a scalable flow cell system has the potential to cost-effectively reach impactful scale.

Water-soluble redox organic molecules “Q” can potentially capture CO2 from diffuse and point sources in an electrochemical flow cell. For example, proton-coupled electron transfer of these molecules (Q+2H++2e- → QH2) can raise the electrolyte pH, leading to the capture of CO2 from air; subsequent electrochemical oxidation of the reduced molecules (QH2 → Q+2H++2e-) acidifies the electrolyte, resulting in the release of pure CO2
[1-2]. The thermodynamic analysis indicates that an idealized cycle requires the minimum work input varying from 16 to 75 kJ/molCO
2 as throughput per cycle increases, with the potential to go substantially lower if CO2 capture or release is performed simultaneously with electrochemical reduction or oxidation. The method appears safe and scalable, as it utilizes non-toxic, non-corrosive, non-volatile and potentially low-cost organic molecules.

An alternative CO2 capture mechanism, which appears to operate in parallel to this pH swing mechanism, is a nucleophilicity swing in which the electrochemically reduced species spontaneously forms a CO2 adduct, Q(CO2)2
2
-, which releases its CO2 upon electrochemical oxidation.

In spite of the advantages in thermodynamic minimum and sustainable electrochemical processes, oxygen intolerance of the reduced molecules (QH2) has limited its application to direct air capture (DAC) due to reversible chemical oxidation of QH2 back to Q by atmospheric oxygen. Here, we report reduced Q species with improved resistance to oxidation by air. The air tolerance of the reduced Q with captured CO2 was evaluated under air exposure and tracked by 1H NMR. From day-1 to day-9, an NMR sample was loosely capped and stored in lab air. There was no sign of chemical changes in the NMR spectra for the first 5 days, and the peaks of Q in the oxidized state did not appear before the ninth day. The air stability of Q(CO2)2
2
- within the first five days suggests the feasibility of utilizing Q for a CO2capture/release cycle in the presence of oxygen that takes << 5 days.

We will report the results of molecular engineering efforts to further improve molecular stability of the reduced form under oxygen.

[1] Jin, S.; Wu, M.; Gordon, R. G.; Aziz, M. J.; Kwabi, D. G. pH swing cycle for CO2 capture electrochemically driven through proton-coupled electron transfer, Energy Environ. Sci., 2020, 13, 3706-3722.

[2] Jin, S.; Wu, M.; Jing, Y.; Gordon, R. G.; Aziz, M. J. Low energy carbon capture via electrochemically induced pH swing with electrochemical rebalancing, Nature Communications, 2022, 13, 2140.