bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Advances in XPS Analysis of Battery Materials
Authors: Artyushkova Kateryna , Zaccarine Sarah , Mann Jennifer 
Published: February 2024

Energy storage (batteries, capacitors) and conversion (solar cells) systems are increasing demand for vehicles, mobile electronics, and other areas as alternatives to fossil fuels.These systems are complex and multi-component with many materials and interfaces that are difficult to handle and characterize. To optimize materials properties and improve battery lifetimes, there is a pressing need for physicochemical characterization approaches with air-free handling capabilities, high spatial resolution, the ability to analyze buried interfaces without damaging the chemistry, and the need to bridge the gap by in situ and operando surface analysis.
Developments in X-ray Photoelectron Spectrometers (XPS) open up new capabilities to address these challenges. In this talk, I will discuss how we can overcome obstacles in analyzing battery materials using:

Inert environment transfer vessel: This allows for handling battery materials in an air-free environment, which is essential for preventing oxidation and other degradation reactions.

Microprobe X-ray source with <5 µm spatial resolution: This provides high spatial resolution for analyzing small areas of interest, such as SEI, dendrites and other features.

Hard X-ray source and cluster ion gun source: These allow for the analysis of buried interfaces not accessible by conventional soft X-ray XPS.

In situ energy gap measurements: These allow for the study of the changes in the electronic structure of battery materials as they are cycled, which can provide insights into the mechanisms of charge storage and discharge.

Operando XPS experiments: These allow for the study of the changes in the surface structure of battery materials as they are operating, which can provide insights into the factors that affect their performance.

Figure 1
Battery Thermalization for Operando Synchrotron Powder Diffraction: Application to the Ca-TiS2 System
Authors: Houdeville Raphaëlle , Fuentes Victor , Fauth Francois , Palacin M. R. 
Published: February 2024

Characterizing electrode materials and understanding its behavior during redox process is a key factor for battery improvement. In Situ techniques on Operando batteries are of particular interest since they do not only probe the material during the electrochemical process but avoid its hazardous and tedious extraction and transfer under inert atmosphere from an electrochemical cell to e.g. capillaries, to perform Ex Situ data collection. Synchrotron based techniques –absorption and diffraction – together with improved detectors, are now intensively used in such In Situ studies on Operando batteries since they allow fast and real time data acquisition during the electrochemical, ion (des-)insertion, process. So far most In Situ X-ray powder diffraction studies on Operando batteries are performed at room temperature using either coin cells or so called Leriche cells [1] (pouch cells, despite widely used for spectroscopy, are generally not favored for diffraction since the container material produce additional Bragg peaks). At ALBA we slightly modified both types of cells: Leriche type and more widespread used CR2032-type coin cells so as to perform data collection in temperature range -10° – 100° C. (see picture)
Both types of cell have been used to study the intercalation of calcium in TiS2, previously determined by Ex Situ powder diffraction [2]. We managed to collect powder patterns operando at 60°C, 45°C and room temperature. (Des-)Insertion of solvated Ca2+ in TiS2 was favoured by temperature, its signature being the appearance of a new phase with a first diffraction peak at very low angles (~17.7 Å in terms of d-spacing). The process was found to be solvent dependent and reversible upon oxidation, which differs from Li cells where a similar process was observed.[3]
Either of these thermalized cells can be used at CELLS-ALBA synchrotron for Power Diffraction on BL04-MSPD beamline or hard X-ray Absorption Spectroscopy (XANES/EXAFS) on BL22-CLEASS, and since 2023 also using simultaneous Powder Diffraction and hard X-ray Absorption Spectroscopy in BL16-NOTOS beamline. Moreover, the Leriche setup is also designed to fit for a use in laboratory X-ray diffractometers, in both reflection and transmission.

Leriche et al. (2010). J. Electrochem. Soc., 157(5), A606-A610.

Tchitchekova et al (2018). Chem. Mater 30, 847−856

Houdeville et al. (2021). J. Electrochem. Soc., 168, 030514

Figure 1
Electrodeposition Behavior of Al-Au Alloys in AlCl3-NaCl-KCl-Aucl Molten Salt
Authors: Sugizaki Masaya , Matsushima Hisayoshi , Ueda Mikito , Kawamura Midori 
Published: February 2024

Quartz Crystal Microbalance (QCM) has been used as a highly sensitive mass sensor. This study aims to form porous gold thin films on QCM elements and apply them to highly sensitive gas sensors by attaching selective media. Physical vapor deposition and chemical etching are known methods for forming porous Au thin films. In this study, the electrochemical formation of porous gold films in AlCl3-NaCl-KCl molten salts containing AuCl was investigated. There are few reports about electrodeposition and dissolution potentials of Au in the molten salt electrolyte. As a first step in this study, voltammogram measurements and constant potential electrolysis were performed in the electrolyte, and electrodeposition potentials of Au and Al-Au alloys were discussed.
An electrolyte in this study is a mixture of 61 mol% AlCl3- 26 mol% NaCl- 13 mol% KCl molten salt. The mixture salt was melted at 443 K and AuCl was added to the molten salt. A glassy carbon plate (GC) and a pure Al wire were used as the working electrode and reference electrode, respectively. The GC plate and Au mesh were used as the counter electrode for voltammogram measurement and constant potential electrolysis, respectively. Voltammogram measurements were carried out at potential range from -0.1 to 2.4 V vs. Al/Al(Ⅲ). Constant potential electrolysis was performed in the range from -0.2 to 0.3 V with an electric charge density of 40 C cm-2. The electrodeposits were observed by scanning electron microscopy (SEM) and determined the composition of Al and Au by energy dispersive X-ray spectroscopy (EDS).
Au ions concentration in the electrolyte was 2.5 mmol dm-3. In voltammogram measurements, a small cathodic current was observed at about 0.8 V, then gradually increased from 0.2 V. In the potential lower than 0 V, a drastical increase of cathodic current was observed, which was attributed to Al electrodeposition. When the potential was reversed, large anodic current flowed from 0 V and a small current peak was also observed at 0.2 V. These were considered to correspond to the dissolution of Al and Al-Au alloys, respectively. Furthermore, a relatively large anodic current peak was observed at about 2 V, which was expected to be due to the dissolution of Au. From the results of constant potential electrolysis, the Au concentration in the electrodeposits at -0.1 V and -0.2 V was less than 1 at%. At 0 V, the Au concentration in the electrodeposit increased sharply to 84 at%, and at 0.3 V it increased moderately to 89 at%. From SEM observation, the morphology of the electrodeposits at -0.1 V and -0.2 V was dense, while that at potentials more than 0 V was sponge-like.
Acknowledgements
This work was supported by JST SICORP and JPMJSC2108.
Controlling Selectivity in Electrocatalysis By Ionic Liquids: Oxidation of 2,3-Butanediol on Pt(hkl) Electrodes Modified By [C2C1im][Otf]
Authors: Yang Juntao , Yang Tian , Franz Evanie , Deng Xin , Fromm Lukas , Taccardi Nicola , Liu Zhi , Görling Andreas , Wasserscheid Peter , Brummel Olaf , Libuda Jörg 
Published: February 2024

In heterogeneous catalysis, ionic liquids (ILs) are used as chemical modifiers to control selectivity. In our work, we aim to apply the same concept to electrocatalytic systems.
As a model reaction, we studied the electrooxidation of 2,3-butanediol on the low-index Pt(111), Pt(100) and Pt(110) surfaces in an acidic environment. We modified the surfaces with the IL 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([C2C1Im][OTf]) dissolved in the aqueous electrolyte. The reaction mechanisms on the different surfaces were studied by electrochemical infrared reflection absorption spectroscopy (EC-IRRAS) in combination with density functional theory (DFT).
The oxidation of 2,3-butanediol is highly structure dependent. On Pt(111), the oxidation occurs in two steps, forming acetoin as an intermediate and diacetyl as the final product. On Pt(110), only the first oxidation step takes place, forming acetoin as the final product. No adsorbed COads is formed during the reaction on either surface. On Pt(100), the final product is acetoin. However, adsorbed COads is formed, which acts as a catalyst poison. On Pt(111), already low concentrations of IL (0.001 M) shift the selectivity towards acetoin from 19% to 56%.[1] We propose that the potential dependent co-adsorption of the [OTf]- anion suppresses the adsorption of OH species required for oxidation in the potential region of the second oxidation step. On the Pt(100) surface, IL suppresses the formation of poisoning COads while the surface remains active for the target reaction.[2] Our results demonstrate the potential of ILs to control selectivity in electrocatalytic reactions.
[1] T. Yang, J. Yang, X. Deng, E. Franz, L. Fromm, N. Taccardi, Z. Liu, A. Görling, P. Wasserscheid, O. Brummel, J. Libuda, Angewandte Chemie International Edition
2022, 61, e202202957.
[2] J. Yang, E. Franz, L. Fromm, N. Taccardi, A. Görling, P. Wasserscheid, O. Brummel, J. Libuda, in preparation.
(Invited) Effects of Nano-Structure on the Kinetics of the Oxygen Reduction over N-Doped Carbon
Authors: Nabae Yuta 
Published: February 2024

Nitrogen-doped carbon catalysts for the electrochemical oxygen reduction reaction (ORR) have great potential to substitute precious metal alloy catalysts for the electrochemical synthesis of H2O2 based on a fuel cell setup. Consequently, obtaining a kinetic understanding of nitrogen-doped carbon catalysts in acidic media is essential. Our research group has established a mathematically and experimentally modified RRDE approach to calculate the corresponding kinetic rate constants, which significantly reduced the calculation noise by avoiding a rotation speed study. Furthermore, the overestimation of the 4-e reduction process, which is related to the (2+2)-e pathway (k
2 + k
3) in the catalyst layer matrix, was corrected by studying the effect of the catalyst loading density. The established method was successfully applied to the ORR over Fe/N/C and N/C catalysts in acidic and alkaline media (Table 1). The results indicate that Fe/N/C catalysts follow mixed reduction pathways of 4-e and 2-e reductions in acidic media, and a pure 4-e reduction pathway in alkaline media, whereas the N/C catalyst exhibits a pure 2-e reduction pathway in acidic media, and mixed reduction pathways of 4-e and 2-e reductions in basic media.
Among the catalysts mentioned above, the N/C catalyst is the most promising for the electrochemical synthesis. To minimizing the effect of k
3, introducing mesoporous structure would be beneficial, because the H2O2 produced by k
2 can be smoothly eliminated without the further reduction to H2O by k
3 (Figure 1). In this context, we have synthesized a N-doped mesoporous carbon by pyrolyzing a N and C source in a mesoporous silica, KIT-6, as a hard-template. This synthesis resulted in a mesoporous carbon with a gyroid structure. The electrochemical study has revealed that this catalyst exhibits a quite high selectivity over 90 % to the 2-e reduction in acidic media.

Figure 1
(Invited) Advanced Photoelectron Spectroscopy on Battery Materials: Lessons Learnt on Silicon- Containing Electrodes
Authors: Jeschull Fabian , He Jiarong , Ghamlouche Ahmad , Gehrlein Lydia , Maibach Julia 
Published: February 2024

While Silicon (Si) is being incorporated more and more as an active material in commercial lithium-ion batteries, it is still a topic of intense research and the motivation for these research efforts remains unchanged: Silicon’s large volume expansion during cycling leads rapid capacity fading largely associated with changes in the Si surface chemistry and unstable solid electrolyte interphase (SEI). Using advanced photoelectron spectroscopy (PES) characterization, we have investigated crucial interfaces on Si model systems and Si-containing negative electrodes for Li-ion batteries. Here, we focus on two approaches to influence the SEI composition intrinsically: Binders and electrolytes.
Starting with pristine Si powders, we studied the effect of carboxylic acids as electrode slurry additives on the Si surface chemistry before and after electrochemical cycling [1] using synchrotron PES depth profiling. Further, we used photoelectron spectroscopy to confirm cross-linking in poly-acrylic acid-based binder for Si electrodes and showed that the cross-linking agent pentaerythritol had no negative effect on the SEI thus attributing improved cycling performance to increased binder cross-linking [2].
In silicon/graphite negative electrodes, we used PES to elucidate the influence of fluoroethylene carbonate (FEC) on the degradation phenomena in electrodes with varying silicon content [3]. Finally, photoelectron spectroscopy provided insights into what happens to the SEI on Si-containing electrodes if we replace the classical electrolyte solvent ethylene carbonate with either FEC or glyoxylic acetal-based alternatives [4, 5].
[1] F. Jeschull, H.Q. Pham, A. Ghamlouche, P.K. Thakur, S. Trabesinger, J. Maibach, J. Phys.
Energy
2023, 5 (2), 025002. https://doi.org/10.1088/2515-7655/acbbee.
[2] J. He, C. Das, F. Yang, J. Maibach, Electrochimica Acta
2022, 411, 140038. https://doi.org/10.1016/j.electacta.2022.140038.
[3] A. Ghamlouche, M. Müller, F. Jeschull, J. Maibach, J. Electrochem.
Soc.
2022. https://doi.org/10.1149/1945-7111/ac4cd3.
[4] L. Gehrlein, C. Njel, F. Jeschull, J. Maibach, ACS Appl.
Energy Mater.
2022, 5 (9), 10710–10720. https://doi.org/10.1021/acsaem.2c01454.
[5] L. Gehrlein, C. Leibing, K. Pfeifer, F. Jeschull, A. Balducci, J. Maibach, Electrochimica Acta
2022, 140642–140642. https://doi.org/10.1016/j.electacta.2022.140642.
In Situ Raman Spectroelectrochemical Investigation of Composite Si Nanoparticle-Based Anode for Li-Ion Batteries during (de)Lithiation Process
Authors: Vlčková Zuzana , Jindra Martin , Soukupová Gabriela , Lapka Tomáš , Sonia Farjana , Müller Martin , Červenka Jiří , Fejfar Antonín , Hassouna Fatima , Frank Otakar 
Published: February 2024

The key degradation processes in the composite anode for the Li-ion batteries (LIBs) prepared using Si nanoparticles (SiNPs) with two types of a conductive carbon-based matrix [carbon black (CB) and carbonized polypyrrole (CPPy)] were studied by in situ Raman spectroelectrochemistry (SEC). This combined technique provides non-destructive and real-time monitoring of the chemical and structural changes that occur during battery operation. These processes, such as the crystal lattice changes (expansion/contraction) and possible degradation/amorphization of silicon, the solid electrolyte interphase (SEI) layer formation on the electrode surface during the charge/discharge reactions, and the stability of the carbon-based matrix, significantly affect the performance of Si-based LIBs in many ways. Especially, the large silicon volume expansion (more than 300%) and associated stress cause mechanical instability resulting in rapid capacity fading. To overcome this challenge, various strategies have been proposed, including the use of CPPy as a conductive matrix to prevent large volumetric changes and also provide a pathway for electron transfer.
This study investigates the initial degradation mechanisms such as the formation of the SEI layer, as well as possible structural changes caused by the volume expansion of SiNPs. The shift of the first-order Raman peak of Si at 521 cm-1 which is assigned to crystalline silicon is related to the stress evolution in nanoparticles caused by the (de)lithiation-induced stress (tensile-to-compressive transition) in SiNPs and the native oxide on their surface. Additionally, the detailed in situ Raman measurement of the first lithiation cycle allowed us to detect the decomposition of the electrolyte (LiPF6 in EC/DMC) close to the Si surface which is associated with SEI layer formation. A decrease in the intensity of the Raman vibrational modes (700–1050 cm−1) of EC/DMC corresponding to the decomposition of the electrolyte was observed at reduction potentials of 0.8 V and 0.3 V vs. Li/Li+ corresponding to the same potentials determined by cyclic voltammetry. The Si-based anode containing CPPy as active carbon showed better electrochemical properties (higher charge/discharge capacity and cycling stability) in Li-ion batteries than Si/CB despite the higher conductivity of the latter. The correlation between the chemical structure of the active carbon and the electrochemical properties of the resulting Si-based anodes will be discussed.
Acknowledgment: This work was supported by the Czech National Foundation, Project No. 21–09830S.
(Keynote) Development of Advanced High Surface Area Metal Oxide Aerogels for Oxygen Evolution Reaction Electrocatalysis
Authors: Elbaz Lior 
Published: February 2024

The growing demand to shift energy production to sustainable sources poses some serious challenges. One of the biggest are the intermittent energy (wind and sun). To mitigate this issue, there is a critical need for large energy storage technologies, to store excess energy during the peak hours and carry it over for the rest of the day, weeks, and seasons. The best way to do so is through the Hydrogen Economy. At the heart of this scheme is green hydrogen production using water electrolysis.
There are two distinct chemical reactions that take place in water electrolyzers: the cathodic hydrogen evolution reaction (HER), and the anodic oxygen evolution reaction (OER). Both reaction require catalysts to execute at high rates, and while the HER is considered to be relatively facile and takes place at low overpotentials, the OER requires relatively high overpotentials and high loadings of precious metal catalysts. It is considered the bottleneck reaction. The OER is a four electrons oxidation reaction per generated O2 molecule and proceeds in four distinct reaction steps. This leads to a very sluggish reaction kinetics and high overpotentials to reach viable current densities.
In recent years, more and more non-precious metal OER catalyst have been developed. Most notably is the family of mixed nickel-iron oxyhydroxides (NiFeOOH), which are relatively cheap, selective and efficient catalysts in alkaline media, and their performance has been increased by optimizing the Ni:Fe ratio. One challenge that still remains is to increase the NiFeOOH surface area, and by that the electrochemically active site density (EASD).
In this regard, one class of materials that has been attracting the attention of materials’ scientists in recent years are aerogels. Aerogels can be made from many different materials, such as silicates, carbons, metal organic materials, bio-inspired molecules, metals, and metal oxides. They consist of distinct units which form a porous 3D covalent framework (COF). Because of their diversity, aerogels have many different applications, e.g. as insulators, sensors, or catalysts.
In this talk we will report the synthesis of NixFeyMzOOH aerogels, with a modified easy synthetic method via an epoxide route. These aerogels show much higher utilization of the material and overall increase in mass activity when catalyzing the OER when compared to other NiFeOOH derived materials. They were tested for their OER electrocatalytic activity and to the best of our knowledge these are the first aerogel materials that propagate OER themselves, rather than being used merely as support material for OER catalysts. The catalytic activity depends largely on the Ni:Fe ratio and not the surface area, which can lead to mass transport limitations when too high, showing an optimum for the ratio and the surface area.
Hollow TiO2 Supports for Enhanced Acidic Oxygen Evolution Activity
Authors: King Laurie , Belami Debora , Jonnalagadda Umesh , Fan Wenhao , Kwan James , Regmi Yagya 
Published: February 2024

The usage of scarce and expensive iridium as a catalyst for the acidic oxygen evolution reaction (OER) represents a significant barrier to up-scaling the deployment of proton exchange membrane water electrolysers (PEM-WEs). Accordingly, strategies such as nanostructuring catalysts to increase the electrochemical surface area (e.g. nanoparticles, single-atom catalysts, nanoclusters) as well as investigating mixed metal alloys and oxides (e.g. perovskites, pyrochlores) have been developed with promising half-cell performances. One further approach that has recently gained attention is the deployment of catalyst-supports whereby a high surface area support is used to scaffold the dispersed iridium catalyst.1 Analogous to the selection of a catalyst, the catalyst support must withstand the highly corrosive and oxidising conditions of a PEM-WE anode. Thus, metal oxides such as titanium dioxide are commonly deployed as catalyst-supports for acidic OER. The catalyst-support moiety must also be sufficiently conductive when integrated into the PEM-WE catalyst layers. Otherwise, the cell voltages required to generate sufficient activity will render the device impractical. Accordingly, strategies such as doping, or the addition of conductive layers between the catalyst and support have been investigated.2

In this study we investigate a unique support morphology that affords promising OER activity and stability in acidic electrolyte with high iridium mass activities. Specifically, we deploy a hollow TiO2 catalyst support,3 coated with a Au/Pd interlayer to provide electrical conductivity. The OER activity and stability is initially screened in a rotating disk electrode (RDE) configuration as a function of thermal treatments (reducing vs oxidising) as well as with at various Au/Pd (1 – 5 wt%) and Ir loadings (35 – 50 wt%). Our highest performing catalyst have a mass activity of around 480 A/gIr at 1.60 V vs RHE. The catalysts are subsequently investigated in a membrane electrode assembly (MEA) and subject to 10k accelerated stress test stability measurements. To understand the role of the support morphology, Au/Pd interlayer and iridium loadings on electrochemical performance, we also characterise the synthesised catalysts by (scanning) transmission electron microscopy (STEM/TEM), X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS) and electrical conductivity measurements. Collectively, we report the critical role of the Au/Pd interlayer to enable such high electrochemical performance. We also show that the hollow structure of the TiO2 support may be enhancing mass transport in the catalyst layers.

References

1 A. S. Pushkarev, I. V Pushkareva and D. G. Bessarabov, Energy & Fuels, 2022, 36, 6631–6625.
2 Y. N. Regmi, E. Tzanetopoulos, G. Zeng, X. Peng, D. I. Kushner, T. A. Kistler, L. A. King and N. Danilovic, ACS Catal., 2020, 10, 13125–13135.
3 U. S. Jonnalagadda, X. Su and J. J. Kwan, Ultrason. Sonochem., 2021, 73, 105530.