Time-of-flight Secondary Ion Mass Spectrometry Research Articles

Alterations of the chemical profile of cholesterol in cancer tissue as traced with ToF-SIMS.

Cancer has become one of the leading causes of death, with approximately ten million people worldwide dying from cancer each year. In most cases, cancer spreads to remote organs and develops a resistance to therapy. To reduce the deadly impact of cancer, novel targets for markers for early detection are necessary. Given the notable influence of rapid chemical turnover on isotope effects, the heightened turnover rate of cholesterol in cancer offers a promising way for investigation. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) offers a valuable tool of tracking cholesterol dynamics. Consequently, we employed ToF-SIMS to assess cholesterol alterations, aiming to uncover potential diagnostic vulnerabilities stemming from heightened cholesterol synthesis. Our study explored the chemical profile of cholesterol influenced by cancer cell metabolism using mammary glands from mice, both with and without cancer. Results revealed a significant increase in the fractional abundance of fragment cholesterol peaks (C27H45+) in cancerous tissues, indicating dysregulated cholesterol metabolism within cancer cells. This suggests potential structural weaknesses or incomplete synthesis. Further investigation into carbon isotope incorporation suggests that the isotopic patterns might be due to the integration of heavier carbon isotopes, although these patterns could be affected by other isotopic influences. Nevertheless, understanding isotope effect of cholesterol profiles have the potential to advance our understanding of cancer biology and improve diagnostic approaches.

Thermal transformation of date seeds from nonporous to porous materials: Insights on structural changes using chemical and physical characterization

The comprehension of the structure and morphology of carbonized bio-based materials remains incomplete. Diverse biomaterials have been employed in the carbonization process to create porous materials for various environmental remediation applications, such as air filtration and water treatment. This study explores the impact of pyrolysis temperature on the chemical structure, porosity, and morphology of date seeds. Molecular-level changes in the carbonized date seeds were investigated using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). Wide angle X-ray diffraction (WXRD) illustrated the transition from semi-crystalline to amorphous material. Concurrently, scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) surface area analyses were employed to monitor the alterations in morphology and porosity. The amorphous pyrolyzed date seeds displayed a BET surface area of 117 ± 13 m2 g−1. These findings contribute valuable insights into the structural transformations of date seed chemistry during the carbonization process.

Experimental and analytical procedures for the ToF-SIMS measurement data of membranous structures

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful analytical technique with great application potential in biomolecular matter research. SIMS measurements performed on biological samples, due to their complex structure and the content of many small and large atomic molecular compounds, suffer very rich and complex mass spectra of particles, which characterise the content and physio-chemical properties of examined samples. The proper description and understanding of features appearing in the spectra and, consequently, the final data confirming or rejecting the hypothesis put forward in the experiment, largely depend on the experimenter’s correct understanding of the technique itself and its limitations, knowledge of the tested material and its appropriate preparation. These issues mean that obtaining the right answer to the questions posed in the research hypothesis requires not only the correct conduct of experiments but also the appropriate processing of post-experimental data. This study aims to demonstrate the impact of various analytical and experimental procedures applied to reach proper conclusions from TOF-SIM measurements. These are different types of data normalization, the selection of a so-called region of interest (ROI), the selection of representative secondary ions and specific quantification methods, including a combination of experimental parameters. All these aspects were checked and discussed based on the results of the analysis of pancreatic <i>β</i> cells placed in a PBS solution on silicon wafers.

Delineating the Impact of Transition-Metal Crossover on Solid-Electrolyte Interphase Formation with Ion Mass Spectrometry.

Lithium-metal batteries (LMB) employing cobalt-free layered-oxide cathodes are a sustainable path forward to achieving high energy densities, but these cathodes exhibit substantial transition-metal dissolution during high-voltage cycling. While transition-metal crossover is recognized to disrupt solid-electrolyte interphase (SEI) formation on graphite anodes, experimental evidence is necessary to demonstrate this for lithium-metal anodes. In this work, advanced high-resolution 3D chemical analysis is conducted with time-of-flight secondary-ion mass spectrometry (TOF-SIMS) to establish spatial correlations between the transition metals and electrolyte decomposition products found on cycled lithium-metal anodes. Insights into the localization of various chemistries linked to crucial processes that define LMB performance, such as lithium deposition, SEI growth, and transition-metal deposition are deduced from a precise elemental and spatial analysis of the SEI. Heterogenous transition-metal deposition is found to perpetuate both heterogeneous SEI growth and lithium deposition on lithium-metal anodes. These correlations are confirmed across various lithium-metal anodes that are cycled with different cobalt-free cathodes and electrolytes. An advanced electrolyte that is stable to higher voltages is shown to minimize transition-metal crossover and its effects on lithium-metal anodes. Overall, these results highlight the importance of maintaining uniform SEI coverage on lithium-metal anodes, which is disrupted by transition-metal crossover during operation at high voltages.

Effect of polyaspartic acid as an environmental-friendly depressant on flotation separation of chalcopyrite from arsenopyrite

The selection of environmental-friendly and high-efficiency depressants is a major research priority for removing arsenic from copper concentrates. The polyaspartic acid (PASP, (C4H6O3N) n) was used for the selective separation of chalcopyrite from arsenopyrite to explore the depression mechanism of PASP using micro-flotation experiments, contact angle measurements, zeta potential measurements, fourier transform infrared spectroscopy (FT-IR), local electrochemical impedance (LEIS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The flotation results showed that recovery of chalcopyrite reached up 90.18 %, while the recovery of arsenopyrite was only 23.48 %, when the PASP was added. The contact angle measurements and zeta potential measurements showed that PASP selectively adsorbed on the surface of arsenopyrite, but was not adsorbed on the surface of chalcopyrite. The FT-IR tests further confirmed that the adsorption was chemical adsorption. The LEIS tests revealed that the conductivity of arsenopyrite surface increased with the addition of PASP, while chalcopyrite was almost unaffected. The ToF-SIMS analyses illustrated that the arsenopyrite with Fe and As sites was reacted with —NH– in the structure of PASP to form stable complexes. Finally, the mechanism diagram was designed to provide insight into the adsorption mechanism of PASP on the surface of arsenopyrite and its selective inhibition of arsenopyrite.

A New Approach in Surface Modification of Manganese Based Cathode Materials for Enhanced Performance in Zinc Aqueous Batteries

With the growing demand for sustainable and environmentally friendly energy storage solutions, zinc-aqueous batteries have emerged as promising alternatives to conventional lithium-ion batteries. Among the various cathode materials studied for zinc-aqueous batteries, manganese dioxide (MnO2) has garnered significant attention due to its high theoretical capacity, abundance, and non-toxic nature. However, the intrinsic limitations of MnO2, including low electrical conductivity and sluggish kinetics, have hindered its practical application. To address the aforementioned limitations, we present a new approach in surface modification of KxMnO2 cathode with improved electrochemical performance for zinc-aqueous batteries.In this study, the KxMnO2 cathode material’s surface has been fluorinated, that enhances capacity retention of the material and effectively improves the overall electrochemical performance. Structural and morphological characterizations of the surface modified KxMnO2 were performed using operando X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), X-ray Absorption Near Edge Spectroscopy (XANES) and thermogravimetric analysis (TGA). Furthermore, X-ray photoelectron spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) confirmed the successful fluorination of the material surface.Electrochemical tests, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), were conducted to evaluate the performance of the surface fluorinated KxMnO2 cathode in comparison to pristine KxMnO2. The results demonstrated a remarkable improvement in the specific capacity, rate capability, and cycling stability of the modified cathode. The improvement of electrochemical performance can be attributed to the effect of the fluorine element, which alleviates the structural degradation of KxMnO2 during cycling. The improved electrochemical performance of the KxMnO2 cathode paves the way for the development of high-performance, cost-effective, and environmentally friendly zinc-aqueous batteries.

Ionic Liquid Initiated Corrosion Products on Steel

Ionic liquids (ILs ) are achieving great interest as electrically addressable lubricants. The demands of lubrication of inaccessible systems, such as wind turbines, coupled with the lubrication paradigm shift engendered by electric vehicles makes IL lubricant additives extremely attractive. The interaction of ILs with steel surfaces and initiation of corrosion need to be urgently addressed, since ILs are in principle organic salts, and water is ubiquitous , even at ppm levels. In this study we have applied a set of surface sensitive advanced techniques, such as Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Confocal Raman Microscopy, Nano-IR and FTIR microscopy as well as scattering GISAXS, to investigate the formed corrosion products in tribo films containing designer ionic liquids at steel surfaces. The trihexyl-(tetradecyl)phosphonium-bis(oxalato)borate [P6,6,6,14][BOB] ionic liquid and a specially deposited AISI 52100 steel were used in this study. The IL breakdown and various surface-formed corrosion products were imaged and analyzed. The formation of iron oxides and various borate and phosphate-containing products, and their interrelation, is observed and mechanistically discussed.

Designing Fluorine-Free Electrolytes for Practical Sodium Metal Anodes and Seawater Batteries

Fluorine (F) is regarded as a key element in electrolytes for sodium metal anodes (SMAs) because of the formation of NaF containing solid–electrolyte interphase (SEI) layers; however, the high-cost and HF formation issues experienced by F-based electrolytes should be addressed. Herein, F-free, cost-effective 1 M NaBH4/ether-based electrolytes are proposed, motivated by the recent speculation that NaH is a “good SEI layer.” The time-of-flight secondary ion mass spectrometry (TOF-SIMS) results of sodium metal electrodes after galvanostatic cycling demonstrated that NaH is a major component of the SEI layer. In addition, the native oxide surface of sodium was converted into NaH and NaBO2 after soaking in the electrolytes, implying that “SEI reconstruction” occurred by chemical reduction. Accordingly, significantly longer cyclability was obtained in the Na‖Na symmetric cell (1200 h, 1 mA cm−2, 1 mA h cm−2) than in F-based electrolytes. In seawater batteries (SWBs), 1 M NaBH4/DEGDME (diethylene glycol dimethyl ether) delivers higher power density (2.82 mW cm−2 vs. 2.27 mW cm−2) and cyclability (300 h vs. 50 h) under 1 mA cm−2 than 1 M NaOTf/TEGDME (tetraethylene glycol dimethyl ether), which is commonly used in SWBs. In conclusion, two novel contributions of this study include the demonstration that NaH can work as a “good SEI layer” apart from NaF and the proposal of a cost-effective, F-free electrolyte for practical and large-scale SWBs.

Probing the Dynamic Na Metal/Nasicon Interface in Sodium-Ion Batteries

Interest in solid-state sodium-ion batteries (SSIBs) have resurged remarkably as a means of diversification in energy storage devices to address climate issues and further propelled by the movement of ‘Beyond-Li’. State of the art SSIBs not only offer energy security and sustainability but also comparable power and energy densities to their counter-parts. Yet to fully capitalise on the technology, the fundamental processes taking place between the anode and interface or ‘point of contact’ needs to be understood. Previous iterations of SSIBs have employed various solid-electrolyte candidates – most notable being beta-alumina – however with the recent advancements in synthesis and dopants more prominent solid-electrolytes have become interesting, one in particular being NaSICON (Sodium Super Ionic Conductor). NaSICON has several advantages, one of which is the reduction in operating temperatures of SSIBs due to its inherent fast sodium-ion transport1. This would broaden the potential applications of SSIBs, making the technology more accessible to a wider range of markets.Current perspectives on NaSICON solid-electrolytes have focused on optimising conductivity through means of additive dopants2 and synthesis procedures3. Yet at present, the understanding of the fundamentals of interfacial inhomogeneities that affect the performance of these materials in SSIBs is limited. With consideration of the direct implications on performance that surface chemistry has, understanding of this is paramount.Evaluation of the chemical evolution of the Na metal/NaSICON interface has been achieved through assessing the changes of the chemical landscape that take place at the surface and near-surface, through surface characterisation techniques that probe the area of interest at varying depths – X-Ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). This has been conducted on samples that have been electrochemically cycled and comparison made to samples in pristine condition. The compositions used to conduct this investigation are Na3Zr2Si2PO12 and Na3.4Zr2Si2.4P0.6O12 – the latter of which has been shown to have one of the highest room temperature sodium-ion conductivity4. Through this, the electronic structure, and hence chemical state, can be deduced alongside a 3D chemical map that will correlate surface chemical changes with electrochemical performance. Thus, a preliminary means of understanding the fundamentals of chemical evolution can be established. References Lu, G. Xia, J. P. Lemmon, Z. Yang, ‘Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives’, Journal of Power Sources, Vol. 195, p. 2431-2442, 2010. Samiee, B. Radhakrishnan, Z. Rice, Z. Deng, Y. Meng, S. Ong, J. Luo, ‘Divalent-doped Na3Zr2Si2PO12 natrium superionic conductor: Improving the ionic conductivity via simultaneously optimizing the phase and chemistry of the primary and secondary phases’, Journal of Power Sources, Vol. 347, p. 229-237, 2017. Jalalian-Khakshour, C. Phillips, L. Jackson, T. Dunlop, S. Margadonna, D. Deganello, ‘Solid-state synthesis of NASICON (Na3Zr2Si2PO12) using nanoparticle precursors for optimisation of ionic conductivity’, Journal of Materials Science, Vol. 55, 2020. Ma, C-L. Tsai, X-K. Wei, M. Heggen, F. Tietz, J. T. S. Irvine, ‘Room temperature demonstration of a sodium superionic conductor with grain conductivity in excess of 0.01 S cm−1 and its primary applications in symmetric battery cells’ J. Mater. Chem. A, Vol. 7, p. 7766-7776, 2019.

Deposition Mechanism, Structure and Corrosion Protection of ZrO2-Based Conversion Coatings on AA6060 Primary and Recycled Aluminum Alloys

Chemical conversion coatings (CC) are amongst the most common surface pretreatments for aluminium alloys before further organic coating steps. The presence of a conversion layer can increase the resistance towards underpaint corrosion such as filiform corrosion (FFC). Here we explore the deposition mechanism, structure and protective properties against FFC of a ZrO2-based CC on AA6060 aluminium alloy by means of electrochemical techniques as open circuit potential measurements, potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (dEIS). Surface composition and elemental distribution are characterized by X-ray photoelectron spectroscopy (XPS), Glow Discharge Optical Emission Spectroscopy (GD-OES) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The variation of important parameters such as charge transfer resistance and capacitance during the conversion layer deposition gives insight into the deposition mechanism. GD-OES and XPS shed light into the structure and composition of the formed CC layer constituted of a mixture of Zr (hydr)oxides based products, redistribution of alloy elements and the nature of deposited additives. Finally, FFC tests reveal a comparable performance between primary and recycled alloys.

Mitigating Chemo-Mechanical Degradation in Sulfide-Based All-Solid-State Batteries Comprising Sulfur Composite Cathode and Li–Si Alloy Anode

In this study, all-solid-state batteries consisting of an Li2S5–P2S5 (LPS) glass electrolyte, a sulfur/LPS glass/carbon composite cathode, and an Li–Si anode are prepared and tested under high cut-off voltage conditions (0.5–3.7 V) to elucidate the effect of LPS redox activity on the chemo-mechanical stability of LPS-based cells. The cell cycled in the voltage range 0.5–3.7 V exhibits unstable charging behaviors and voltage noise, with substantial LPS oxidative decomposition. X-ray photoelectron spectroscopy and impedance spectra analyses of a three-electrode system reveal that the cathode resistance is remarkably increased by the oxidative decomposition of LPS when the cell is charged to 3.7 V, which induces dendritic lithium growth at the anode side, resulting in a micro-short circuit through the electrolyte. Composite anodes of Li3PS4 glass+Li–Si alloy (Type 1) and Li3N+LiF+Li–Si alloy (Type 2) are also prepared for all-solid-state batteries (ASSBs) with LPS glass electrolyte and sulfur/LPS glass/carbon composite cathode. Using a three-electrode system, the anode and cathode potentials are separated, and their polarization resistances are individually traced. Even under high-cutoff-voltage conditions (3.7 V), Type 1 and 2 cells are stably cycled without voltage noise for >200 cycles. Although cathode polarization resistance drastically increases after 3.7 V charge owing to LPS oxidation, LPS redox behavior is fairly reversible upon discharge–charge unlike the non-composite alloy anode cell. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis reveals that the enhanced cyclability is attributed to uniform Li–Si alloying throughout the composite anode, providing more pathways for lithium ions even when these ions are over-supplied via LPS oxidation. These results imply that LPS-based cells can be reversibly cycled with LPS redox even under high-cutoff voltages, as long as non-uniform alloying (lithium dendrite growth) is prevented.

Adsorption of 2-Mercaptobenzothiazole Organic Inhibitor and Its Effects on Copper Anodic Oxidation in Alkaline Environment

2-Mercaptobenzothiazole (2-MBT) is well established as an effective organic corrosion inhibitor for the protection of copper and other metals. The presence of heteroatoms (2 sulphur and 1 nitrogen) in its structure, enables it to bond to the metallic substrate and form a protective barrier layer on the surface which restricts the pathways for the corrosive ions to the metal surface. However, despite numerous works discussing the inhibiting properties on copper, several questions remain, notably regarding the role played by the surface native oxide on the bonding mechanisms, the stability, and the inhibition efficiency of the organic film formed in various environments.In this work, the adsorption of 2-MBT on copper and its effects on anodic oxide growth in a strong alkaline medium (0.1 M NaOH solution) were investigated. Various cathodic pre-treatment methods were applied to modify and control the native oxide-covered Cu surface during the formation of the inhibitor layer. Cyclic voltammetry (CV) tests were performed to determine how the growth of anodic Cu(I) oxide is altered by the 2-MBT organic inhibitor layers pre-adsorbed in different pre-treatment conditions. Additionally, X-ray photoelectron spectroscopy (XPS) and time-of-flight – secondary ion mass spectrometry (ToF-SIMS) were used to investigate the bonding mechanisms of the 2-MBT molecule to the copper surface, including the role of surface native oxides in the formation of the interface with the inhibitor, the effect of increased exposure time to the inhibitor, the stability of the organic inhibitor layer upon anodic polarisation, and the oxide growth upon anodic polarization. The absence of chlorides eliminates their interference in the understanding the oxidation process in a 2-MBT-containing alkaline solution. Additionally, anodic oxidation is studied in the Cu(I) potential range, which allows us to evaluate the effects of 2-MBT on the oxide layer that forms directly on the bare metallic substrate.The results show that 2-MBT significantly impedes the growth of the passivating Cu(I) oxide by forming a multilayered organic film with the inner layer chemisorbed to the surface. A major factor influencing the formation and properties of the organic barrier layer is the presence and structure of the interfacial native oxides on which it forms. The 2-MBT molecules bond to the copper substrate mostly via its sulphur atoms along with a small fraction of the nitrogen atoms also bonding to the metallic substrate. Additionally, there is an interaction between the inhibitor molecules and copper released from the surface to form metal-organic complexes in the outer layers of the thicker films. Longer exposure times to the inhibitor of a surface with negligible oxides increased the efficiency of the organic barrier layer in impeding the growth of anodic oxide.Upon anodic polarisation, the 2-MBT barrier layer grows in thickness, with inclusion of Cu-2-MBT complexes. It is proposed that the thiolate form of 2-MBT, which is the dominant conformer in an alkaline environment, allows for additional bonding possibilities to the Cu atoms and Cu(I) ions of or released from the surface oxide, forming Cu-2-MBT complexes that deposit on the surface and thus increasing the thickness of the organic barrier layer. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Advanced grant agreement No. 741123, CIMNAS).

Characterization of Sulfur-Rich Microbial Organic Matter in Jurassic Carbonates Using Laser-Assisted Mass Spectrometry.

Laser desorption-ionization mass spectrometry (MS) shows great potential for in situ molecular analysis of planetary surfaces and microanalysis of space-returned samples or (micro)fossils. Coupled with pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) in ESA's ExoMars project, this technique could help assess further the origin of sulfur-bearing organic matter (OM) recently detected on Mars. To unravel this potential, we analyzed sulfurized microbial OM from ca. 150 million year-old carbonates with laser desorption-ionization mass spectrometry (single- and two-step: LDI-MS and L2MS), in comparison with time-of-flight secondary-ion mass spectrometry (ToF-SIMS), gas chromatography-mass spectrometry (GC-MS), and Py-GC-MS. We show that LDI-MS and L2MS readily detect sulfur-bearing moieties such as (alkyl)thiophenes and (alkyl)benzothiophenes. The mineral matrix, however, made the identification of sulfur-bearing molecules challenging in our L2MS experiment. The dominance of small aromatic hydrocarbons (≤14 carbons) in the LDI-MS and L2MS of the extracted soluble and insoluble OM and of the bulk rock is consistent with the low thermal maturity of the sediment and contrasts with the predominance of larger polycyclic aromatic structures commonly observed in meteorites with these techniques. We detected inorganic ions, in particular VO+, in demineralized OM that likely originate from geoporphyrins, which derive from chlorophylls during sediment diagenesis. Finally, insoluble OM yielded distinct compositions compared with extracted soluble OM, with a greater abundance of ions of mass-to-charge ratio (m/z) over 175 and additional N-moieties. This highlights the potential of laser-assisted MS to decipher the composition of macromolecular OM, in particular to investigate the preservation of biomacromolecules in microfossils. Studies comparing diverse biogenic and abiogenic OM are needed to further assess the use of this technique to search for biosignatures.

Construction of Stable Li2O‐Rich Solid Electrolyte Interphase for Practical PEO‐Based Li‐Metal Batteries

AbstractPolyethylene oxide (PEO)‐based solid polymer electrolytes (SPE) have garnered recognition as highly promising candidates for advanced lithium‐metal batteries. However, the practical application of PEO‐based SPE is hindered by its low critical current density (CCD) resulting from undesired dendrite growth. In this study, a PEO‐based SPE that exhibits an ultra‐high CCD (4 mA cm−2) is presented and enhanced lithium ionic conductivity through the incorporation of small amounts of P2S5 (PS). The crystalline Li2O‐rich and P/S‐containing solid electrolyte interphase (SEI) is revealed by cryo‐electron microscope (cryo‐EM) and Time of flight secondary ion mass spectrometry (TOF‐SIMS), which inhibits dendrite growth and adverse reactions between SPE and reductive lithium, thus offering a spherical growth behavior for dendrite‐free lithium metal anode. Consequently, utilizing the PS‐integrated SPE, a Li‐Li symmetric cell demonstrates reduced resistance during operation, enabling stable cycles exceeding 200 hours at 0.5 mA cm−2 and 0.5 mAh cm−2, a stringent test condition for PEO‐based electrolytes. Moreover, a Li/SPE/LiFePO4 (LFP) pouch cell exhibits 80% capacity retention after 100 cycles with 50 µm Li and 30 µm PEO electrolyte, showcasing its potential for practical applications.

MXene and silk fibroin peptide team up to build a 1+1>2 in situ SEI film

The utilization of solid-state lithium-ion batteries (SLIBs) is envisaged for the next generation of energy storage devices due to their exceptional energy density. Nonetheless, for practical applications of SLIBs, it is crucial to address the challenges associated with unstable interfaces and poor electrochemical performance. By employing silk fibroin peptide (SFP) and MXene, we successfully achieved the in-situ generation of uniform solid electrolyte interphase (SEI) films through the design of modified interfaces. The incorporation of -NH2 groups from SFP and the -F terminus from MXene facilitated the formation of Li3N and LiF, thereby enabling selective localization and controlled SEI film growth as confirmed by the time-of-flight secondary-ion mass spectrometry (TOF-SIMS) analysis. The Derjaguin-Müller-Toporov (DMT) modulus demonstrated the robustness of the SEI film. This phenomenon enhances interfacial stability, promotes lithium-ion nucleation, suppresses dendrite growth, and improves overall electrochemical performance during battery operation. The presence of -NH2 possessing a lone pair of electrons exhibited excellent lithophile properties that facilitated micro-complexes formation with lithium ions, thereby promoting lithium salt dissociation and facilitating the lithium-ion migration within systems. Furthermore, the interface-modified polymer electrolytes (PEs) demonstrated an impressive ionic conductivity of up to 1.16 × 10−3 S cm−1, along with a favorable transference number of lithium ions (tLi+) of 0.57. Notably, the modified PEs significantly contributed to stable battery operation at room temperature (RT), exhibiting an initial discharge capacity of 117.6 mAh g−1 at 5 C. This innovative strategy involving modification at the interface level represents a significant advancement towards achieving stable operation in high-energy SLIBs.

Deciphering the Nature of an Overlooked Rate‐Limiting Interphase in High‐Voltage LiNi0.5Mn1.5O4 Cathodes: A Combined Electrochemical Impedance, Scanning Electron Microscopy and Secondary Ion Mass Spectrometry Study

AbstractHigh‐voltage cathode active materials, such as LiNi0.5Mn1.5O4 (LNMO), are of major interest for the development of high‐energy lithium‐ion batteries. However, it has been reported that composite cathodes based on high‐voltage active materials suffer from high impedances and low rate capabilities. The origin of the high impedances has not yet been clarified. Here, we use a combination of electrochemical impedance spectroscopy (EIS), focused ion beam/scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (FIB/SEM/EDX) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) for showing that in the case of LNMO‐based cathodes, a major part of the cathode impedance is related to the formation of a passivating interphase on the Al current collector. Remarkably, the impedance of this interphase can be mitigated by the targeted formation of a distinct passivating interphase, namely on the surface of the LNMO particles. The interplay between these interphases is discussed.

Time‐of‐flight secondary ion mass spectrometry and X‐ray photoelectron spectroscopy protocol for the analysis of organic multilayers

With the development in the early 2000s of new cluster ion sputtering sources, a reliable analysis of organic multilayers and interfaces has become possible. Nowadays, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and X‐ray photoelectron spectroscopy (XPS) depth profiling are routinely used to investigate organic stacks. However, analysis beams can cause bond scission or beam‐induced degradations that accumulate in buried layers. We developed a correlative protocol that minimises damages related to analysis beams. It uses a shallow angle bevel crater fabricated inside the ToF‐SIMS analysis chamber. With this preparation method, the in‐depth information is displayed over the surface of the bevel crater. XPS profiles and high‐resolution spectra paired with ToF‐SIMS images enable an easy identification of the organic layers and complete understanding of their chemistry. The reduction of beam‐induced degradation is achieved by minimising the acquisition times, therefore beam exposure on materials. Finally, an important advantage of this preparation method is that the analysis can be performed on exactly the same spot by multiple techniques. Several ToF‐SIMS and XPS acquisitions can be carried out with various parameters (investigation of backscattered Arn+ cluster ion fragments, tandem MS imaging…) as well as analysis with other techniques that possess limitations in spatial resolution and/or inaptitude to probe buried layers such as Raman or AFM.

Profiling a Low Emissivity Glass Coating with ToF‐SIMS and Machine Learning

AbstractCharacterization of multilayer coatings in 3D presents many challenges, as composition can change by area and by depth. Compositional characteristics of the interior of multilayer coatings emerge during analysis, so are frequently discovered only through exacting retrospective investigations. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) can be used to elucidate such complex systems; however, data analysis is a challenge. In this work a detail presentation is done of 3D chemical characterization of a low emissivity (low‐E) double silver coating on glass using ToF‐SIMS and machine learning. An unsupervised machine learning technique, the self‐organizing map with relational perspective mapping, is used to visualize the chemical similarity between different layers of the low‐E film. Repeating layers are easily identified at the single‐voxel level, based on their entire mass spectra, and are classified as chemically indistinguishable. All major film components are identified, including the use of SnO2 as a dielectric, ZnO seeding layers, TiOx blocking layers, a Zn base layer, and a TiOx topcoat. The thin optically active silver layers are examined in detail, demonstrating subtle chemical changes with depth. This technique provides excellent insight into manufacturing processes and production challenges and has excellent potential in forensic applications.

Chemical and Topographical Changes upon Sub‐100‐nm Laser‐Induced Periodic Surface Structure Formation on Titanium Alloy: The Influence of Laser Pulse Repetition Rate and Number of Over‐Scans

Titanium and its alloys are known to allow the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi‐method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near‐infrared ps‐laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near‐surface chemical analyses hard X‐ray photoelectron spectroscopy (HAXPES) and depth‐profiling time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non‐ablative laser‐induced near‐surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat‐accumulation effects.

Solute Enrichment in the Fusion Zone during Resistance Spot Welding of a Third Generation Advanced High Strength Steel

Resistance spot welding is a critical joining technique in automobile assembly. The load carrying properties of spot welds are generally accepted to correlate with weld diameter, which increases with increasing weld current or duration. The formation of a softened layer, or weld halo, surrounding the fusion zone in a spot-welded third generation (Gen3) advanced high strength steel (AHSS) was recently reported in the literature. To optimize weld performance by schedule design, it is necessary to understand the halo formation characteristics and potential impacts. Accordingly, welding of a Gen3 AHSS was performed using weld times between 130 – 1300 ms. Microhardness mapping characterized weld microhardness and the evolution of the halo during welding. Electron probe microanalysis and timeof-flight secondary ion mass spectrometry enabled measurement of solute distributions through the weld halo, while scanning electron microscopy was used for microstructural characterization. The solidified structure was examined using light-optical microscopy, and with the microhardness and compositional data, used to infer the mechanism by which the halo forms during welding. It was found that the halo develops due to solute rejection from a cellular solidification front that advances towards the center of the fusion zone while weld current is applied. Extended weld times increase the size of the weld halo and the solute content of the inner fusion zone. The decrease in weld halo microhardness and the increase in inner fusion zone microhardness is largely explained by the changes in local carbon content associated with halo formation.