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An In Situ ATR‐FTIR Electrochemical Cell for the Study of Battery Processes: Design, Implementation, and Data Analysis
No full textInternational audiencePhenomena occurring in the electrolyte as well as the interfaces with the electrodes, such as Li + solvation/desolvation and solid–electrolyte interphase formation, govern the performance and safety of Li‐ion batteries. In this article, a dedicated, spring‐loaded operando attenuated‐total‐reflectance Fourier‐transform infrared cell is presented, enabling quantitative, time‐resolved probing of the electrode–electrolyte processes under electrochemical examination. The optical design is based on a 45 ∘ incidence diamond waveguide, while the electrochemical setup comprises a gas‐tight stainless steel body. The procedure for preparing the self‐supported electrode and the acquisition protocol are also presented, together with a reproducible analysis workflow for tracking solvated versus free electrolyte solvent species without baseline subtraction. Representative measurements on composite tin electrodes validate the ability of the setup to resolve band shifts and intensity changes linked to Li + coordination and electrolyte reduction. The methodology generalizes to diverse negative‐electrode chemistries and provides molecular‐level insight into battery phenomena under electrochemical operating conditions
A dual-phase strain-transformable zirconium alloy with exceptional yield strength (1.2 GPa) and low elastic modulus (70 GPa) via TWIP and phase reversion
No full textInternational audienceThe present study focuses on the development of a novel Zr-12Nb-3Sn alloy displaying a body-centered tetragonal (BCT) / β dual-phase microstructure and engineered to achieve a superior combination of high strength and low elastic modulus. The BCT phase is shown to play a critical role in enhancing strength without increasing elastic modulus. Comprehensive analyses using in situ straining electron backscatter diffraction (EBSD) experiment and transmission electron microscopy (TEM) were conducted to characterize the microstructure of the BCT phase and the associated deformation mechanisms, including dislocation slip, stress-induced reversion from BCT to β transformation, and mechanical twinning. The present findings reveal that the BCT phase and mechanical twinning both contribute to material strengthening, whereas the stress-induced reversion of the BCT phase to β acts as a mechanism for stress relaxation. As a result, the alloy demonstrates exceptional mechanical performance, achieving a yield strength exceeding 1200 MPa, an elastic modulus of approximately 70 GPa, and an elongation of ~13%
How Particle Size Affects Consolidation Behavior, Strain and Properties of Li 6 PS 5 Cl Fast Ionic Conductors
No full textInternational audienceSolid‐state battery fabrication requires the densification of solid electrolytes to achieve optimal cycling performance and high energy density. However, the underlying compaction mechanisms of these electrolytes remain poorly understood. Here, we investigate the effect of pressure consolidation on the ionic conductor Li 6 PS 5 Cl with particle size distributions (PSD) ranging from 4 to 40 µm. Heckel analysis reveals that samples with smaller PSDs exhibit higher compressibility at lower pressures. X‐ray diffraction peak profiling shows that applied pressure induces lattice strain, leading to peak broadening, while pair distribution function analysis demonstrates a reduction in coherence length upon pressing. Dark‐field X‐ray microscopy further provides spatially resolved orientation maps, uncovering intragranular structural variations within individual Li 6 PS 5 Cl agglomerates after compression. To better understand the origin of stress fluctuations, we performed discrete element method simulations using the experimental PSDs. The results indicate that smaller particles and broader PSDs experience higher stresses, whereas monodisperse systems do not exhibit significant stress fluctuations with position or particle size. This suggests that the high strain observed cannot be attributed solely to smaller particles, but rather to size inhomogeneity. Overall, these findings highlight that both particle size and its distribution play a critical role in processing solid electrolytes for solid‐state batteries
Bottleneck size manipulation through the introduction of large-radius alkali ions in Na sites of a NaSICON solid electrolyte: A computational proof of concept
No full textInternational audienceNaSICON electrolytes, such as Na1+xZr2(SiO4)x(PO4)3–x (NZSP), constitute promising candidates for solid-state battery (SSB) development. Research on such fast superionic conductors has primarily focused on two key phenomena acting specifically on Na+ ion migration: (i) the Na-concentration-driven modulation effect and (ii) the incidence of substitution. While numerous experimental and computational studies have established the fundamental role of concerted migration in ionic conduction, the precise influence of bottleneck size along with its dependence on NaSICON composition remains elusive. In view of participating in this research field and following an experimentally tested strategy, suggesting that the migration bottleneck can be expanded by partially substituting diffusing Na+ ions with larger-radius alkali elements, we investigated the impact of the introduction of such point defects (i.e. K+ or Cs+ replacing Na+) on structural and Na+ diffusion aspects in the NZSP crystal structure. A proof of concept of the interest linked to this unconventional doping approach has been searched for. Theoretical investigations relying on density functional theory (DFT) and subsequent kinetic Monte Carlo simulations were involved to unravel interrelations between the ionic radius of the substituting ion and bottleneck sizes, structural changes, diffusion pathways, and ionic conductivity features. Apart from an opening of the bottleneck along the migration path as a common feature, a clear differentiation between both kinds of substituents was evidenced on various aspects, K-NZSP outperforming the undoped counterpart and effectively enabling the maximization of ionic conductivity in these envisaged NaSICON-type matrices. Furthermore, the identification─emerging from this study─of a critical bottleneck size in such systems may contribute to provide a further key clue and lead to well thought-out crystal chemical engineering of improved materials for this research area.</p
LiPON-enabled interfacial engineering: stabilizing lithium metal anodes in halide all‐solid‐state lithium batteries
No full textInternational audienceDespite their enhanced safety and energy density, the practical deployment of halide‐based all-solid-state lithium batteries (ASSLBs) is limited due to their interfacial instability and parasitic side reactions between lithium metal anodes and solid electrolytes. In this study, we systematically explore the use of lithium phosphorus oxynitride (LiPON) as an interfacial functional layer to mitigate these degradation phenomena in halide‐based ASSLBs. LiPON thin films were deposited on lithium metal substrates via magnetron sputtering, resulting in a uniform and amorphous protective layer that effectively stabilizes the interface. Cells modified with LiPON exhibit stable cycling performance for over 2000 h, in stark contrast to unmodified cells, which undergo rapid degradation due to the formation of resistive by‐products such as LiCl. Surface analyses by X‐ray photoelectron spectroscopy, time‐of‐flight secondary ion mass spectrometry, and scanning electron microscopy indicate that the LiPON functional layer facilitates the formation of a robust and high-performing solid electrolyte interphase layer enriched in Li3N and Li3P species, while simultaneously suppressing deleterious reactions at the lithium/halide interface. These results highlight the importance of interfacial engineering in halide‐based ASSLBs and offer new insights and strategies for the development of future high-performance energy storage systems
Turning a solar cell into a catalyst: (Ag,Cu)(In,Ga)Se<sub>2</sub> p–n junction enabling ambient dry reforming of methane
No full textInternational audiencePhotocatalysis driven by solar energy offers a sustainable alternative to thermocatalysis for methane valorization, however large-scale deployment remains limited by catalyst efficiency and scalability. Meanwhile, photovoltaic technologies, though highly developed for electricity generation, still face challenges in costly energy storage and underutilized potential in direct solar-to-chemical energy conversion. In this context, CIGS thin-film solar cells emerge as promising candidates for photocatalytic applications due to their strong light absorption, tunable electronic properties, and industrial scalability. In the present work, we use a thin-film CIGS solar cell plates, re-designed as a monolithic photocatalyst, to drive DRM under ambient conditions. A 2 µm ptype (Ag,Cu)(In,Ga)Se2 (ACIGS) absorber deposited on a soda-lime glass/Mo substrate is overcoated with an ntype CdS layer, forming a p-n junction that couples strong light absorption with built-in charge separation. Under irradiation, ACIGS/CdS plates produce > 2 mmol g cat -1 syngas with ≈ 85 % CO selectivity at ambient conditions, without any external electric power or thermal input. Mechanistic evidence indicates deep CH4 dissociation to surface carbon and hydrogen, with subsequent CO2 reduction by surface carbon to CO. The catalytic plates are air-regenerable under light and exhibit notable stability. Turning a solar-cell design into the catalytic junction tackles efficiency and manufacturing hurdles for CH4/CO2 conversion. Because CIGS and CdS processes already exist at industrial scale, this approach provides a practical route to deployable solar chemical hardware; further gains are expected from junction optimization and selective co-catalysts
Addressing Bottlenecks to Achieve High‐Energy Sodium‐Ion Cells Using Tin Anodes
No full textInternational audienceSodium‐ion batteries (NIBs), as a complementary energy storage device for Li‐ion batteries, are swiftly making their way into high‐power applications market. However, further progress in NIBs requires high energy density. This requires a shift from commonly used hard carbon (HC) anodes to alloy anodes such as Bi, Sn, Sb, etc., while overcoming the problems these materials pose, with regard to volume changes and interfacial reactivity. Although ether‐ and glyme‐based electrolytes mitigate anode reactivity, their poor oxidative stability limits compatibility with high‐voltage cathodes such as Na 3 V 2 (PO 4 ) 2 F 3 (NVPF). Here, we identify glyme oxidation by‐products and detail their cross‐talk–induced poisoning in NVPF|Sn‐HC cells using operando, ex situ, and post‐mortem (electro)chemical characterizations. Based on these insights, we explore mitigation strategies (i) by reducing the Sn‐poisoning via protective SnO coating and (ii) arresting the cross‐talk phenomenon using a chemical trap such as Na‐metal, Na 15 Sn 4, or Na x C between the separators. Both approaches improve cell performance, albeit not fully suppressing electrolyte oxidation, with later enabling to reach near 100% capacity retention over 200 cycles at C/5, also giving some hope for achieving anode‐free Na‐ion cells. Although still present some shortcomings, these strategies offer promising directions for materials design, cell engineering, and electrolyte development toward high‐energy sodium‐ion batteries
Lithium Nitrate as a SEI-Stabilizing Additive in Single-Ion Conducting Polymer Electrolytes for Lithium–Metal Batteries
No full textInternational audienceSingle-ion conducting polymer electrolytes (SIPEs) are among the most promising candidates to realize lithium-metal batteries, which commonly suffer from the risk of lithium dendrite growth and continuous electrolyte decomposition at the lithiumelectrolyte interface. Herein, we report the introduction of lithium nitrate (LiNO3) as an additive into a SIPE based on a poly(ethylene oxide) backbone and grafted perfluorosulfonate anions. By comparing SIPEs with and without LiNO3 concerning, e.g., the charge transport, electrochemical stability, reversibility of the lithium stripping/plating process, electrode morphology and surface composition, it appears that the introduction of LiNO3 yields a thinner, but more robust solid electrolyte interphase, which greatly benefits the eventual performance, Coulombic efficiency, and reversibility of the lithium stripping and plating. The advantageous effect of LiNO3 is finally confirmed in Li|SIPE|LFP solid-state battery cells providing a substantially longer cycle life
Non-resonant plasmon energy transfer processes for catalysis
No full textInternational audienceHow can energy transfer catalysis move beyond fragile molecular light absorbers toward more robust and tunable systems? Here we show that tiny gold nanostructures can act as universal energy donors to activate otherwise inactive gold-based catalysts using light. By introducing a molecular mediator, we demonstrate that the localized energy within the nanoparticles can be passed along through a twostep mechanism, ultimately creating a reactive excited state in the gold complex, even when the light does not directly match its energy levels. Spectroscopic measurements confirm the formation and lifetime of this state and provide clear evidence of successful energy transfer. These results establish how plasmonic materials can drive catalytic reactions through controlled energy flow, opening new opportunities for designing durable and versatile systems for light-driven chemistry
Additive manufacturing by binder jetting of thick electrode for Li-ion battery
No full textInternational audienceBinder jetting (BJ) has drawn attention to its ability to quickly produce complex objects using minimal amount of additives, being suitable for ceramic materials with high porosity. Thanks to these advantages, this additive manufacturing (AM) technique is now of interest in the field of energy storage.A successful NMC622 (LiNi0.6Mn0.2Co0.2O2) thick electrode was fabricated using an aqueous formulation showing a final porosity of 35%. When cycled in half cell configuration versus lithium metal between 4.3 and 3 V at 0.2 mA/cm2, the printed electrode delivers a reversible capacity of 155.2 mAh/g after 10 cycles. These results, presented as a proof of concept, establish Binder Jetting as a possible route to manufacture thick and self-supported electrodes with an areal capacity of 8.33 mAh/cm2 at 0.2 mA/cm2