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Enhanced cycle life and expanded voltage window in aqueous proton full cells using TiO2 negative electrodes with cationic vacancies
No full textInternational audienceAqueous batteries face the challenge of limited energy density due to parasitic gas production from hydrogen and oxygen evolution reactions, particularly at the negative electrode. This study investigates the electrochemical properties and mechanisms of proton intercalation in anatase TiO2 featuring vacancies (Vac-TiO2), stabilized via a low-temperature sol–gel process. XRD refinement analysis, supported by thermal analysis, estimated 17% cationic vacancies, while 1H MAS NMR spectroscopy revealed stabilization of these vacancies by OH groups. The presence of cationic vacancies led to changes in the oxide anion sublattice, which accommodate proton insertion. Electrochemical assessments in acetate buffer electrolyte demonstrated Vac-TiO2’s ability to delay the hydrogen evolution reaction and enhance proton capacity, validated by pH-dependent studies, DFT calculations, and kinetic analyses. Notably, the occurrence of undercoordinated oxide anions was shown to induce the insertion of H+ at higher potential values, and the insertion mechanism was suggested to occur via a solid-solution mechanism. Owing to these features, Vac-TiO2 exhibited superior cyclability and performance compared to pure anatase TiO2, highlighting its potential for sustainable proton intercalation processes. In half-cell configurations, Vac-TiO2 showed a high Coulombic efficiency (CE exceeding 90% after 48 cycles), while full cells (MnO2||Vac-TiO2) demonstrated an excellent cycling stability (CE exceeding 95.4% over 1000 cycles), high power density (10.5 kW·kg–1 vs 6.2 kW·kg–1), and improved self-discharge. This study paves the way for innovative approaches to improving proton intercalation materials, positioning Vac-TiO2 as a viable candidate for next-generation energy storage solutions
Integration of lithium-ion battery recycling into manufacturing through digitalization: A perspective
No full textThe lithium-ion batteries (LIBs) industry has expanded quickly despite technological constraints. Additionally, raw materials supply, end-of-life (EoL) management, and the creation of LIB manufacturing policies are receiving attention. All these concerns could be addressed simultaneously by integrating recycling of EoL cells from the early stages of the LIB manufacturing. This article presents perspectives on how to achieve this holistic integration through the means of digitalization. Various challenges of LIB recycling, and different digitalization tools are discussed, shedding light on the latter’s potential applications and outcomes. Through the use of the discussed tools to create advanced Digital Twins, it would be possible to screen different recycling processing conditions and materials to achieve higher efficiency, increased safety, at a lower cost. In this regard digitalization of LIB recycling process, emerges as the key for achieving a collaborative, sustainable, and efficient battery value chain in the European Union. Lastly, in the view of the growing LIB market, this article is thought to be of interest for recycling stakeholders as they move towards a more circular economy model
Deciphering the Formation Process of 2D to 3D Halide Perovskite Thin Films
No full textInternational audienceThe challenge of obtaining high-performing organo-metal halide perovskite (MHP) thin films of various dimensions for different applications persists. For this purpose, a comprehensive understanding of the growth mechanism and crystallization process of 2D to 3D MHP films during thermal annealing, as the crucial step of most MHP film preparations, is required. Here, we investigate the formation mechanism of MHP which composition varies from 2D to 3D. For this systemic description, eight different initial precursor solution systems and two organic cation spacers have been investigated. They have allowed us to unveil the complex relationship between the growth direction of various phases and the direction of solvent removal. Then, we have comprehensively analyzed the internal structure changes of the MHP low-dimension phases and found a phase splitting phenomenon and revealed a partial spacer elimination during thermal annealing. Our original findings reveal various 2D phase transitions from the film surface to the bottom by a sequential process involving the partial elimination of spacer, phase decomposition, and recrystallization. These generalizable results provide valuable insights for future synthesis optimizations and to produce high-performance MHP film-based devices for a wide range of applications
MARINE BIOMINERALIZATION FOR ENHANCED CORROSION RESISTANCE: INSIGHTS FROM THE ANR MICOATEC PROJECT
No full textInternational audienceConcerns about marine pollution and ecological threats caused by traditional corrosion protection technologies have driven the development of new environmentally friendly anti-corrosion solutions. In recent years, it became clear that microorganisms have the potential to positively impact corrosion behavior, a phenomenon known as MICI (microbiologically influenced corrosion inhibition) [1,2].Although research on MICI mechanisms is still in the beginning, two main mechanisms have been outlined: direct and indirect inhibition. In the first one, the microorganisms are responsible for the segregation of slow-release inhibitors or surfactants or consume oxygen, which affects the cathodic reaction process. The second one, indirect inhibition mechanism, is associated to the formation of a protective layer on the surface of the material due to metabolic activity of microorganisms. In this context, biomineralization attracted the attention of researchers as a solution to inhibit metal corrosion. Being aware of the potential of this microbial induced mineralization phenomenon, the French ANR MICOATEC project (www.micoatec.eu) established a new approach for the development of a bioinspired anticorrosion solution for metal protection based on the biomineralization process observed on an Al-Mg surface during exposure in marine field. The main goal is to translate the natural biotic process into an abiotic technological process for corrosion protection, without replicating the biofilm itself or incorporating active biocompounds into a coating matrix (figure). Three specific objectives were outlined:(1) Understanding the interactions of aluminium alloys with marine biological activity which leads to the formation of a layer that can inhibit corrosion (protective layer).(2) Mastering the growth process and the physico-chemical properties of the protective layer on the alloy surface under the influence of biological activity.(3) And in the longer term, providing the industry with a bioinspired technology for anticorrosion coatings that is more environmentally friendly in order to increase the lifespan of metal structures.The work of the multidisciplinary consortium has led to numerous results in research activities associated with the growth process (WP1) and anti-corrosion properties (WP2) of the protective layer, giving the bases for replication steps (WP3). Among the most important results, we can cite:(i)The Al-Mg surface modifications showed to be strongly influenced by the type of fouling present, notably photosynthetic, such as algae. (ii)The anticorrosion properties of the formed layers are intimately linked to their structure and chemical composition. (iii)Replication in a biotic environment (seawater + salt marshes) is currently being mastered. MICOATEC has allowed to confirm marine biomineralization as a potential new approach for the development of anti-corrosion solutions inspired from biological interactions with metal.Keywords: Aluminium alloy; Marine Corrosion inhibition; Biomineralization; Bioinspired protection solutionAcknowledgements: This work was financially supported by the ANR, in the framework of the MICOATEC project (ANR-19-CE08-0018) coordinated by R.Basséguy-LGC.References:1. Y. Lou et al. “Microbiologically influenced corrosion inhibition mechanisms in corrosion protection: A review”, Bioelectrochemistry, 141 107883 (2021).2. J. Wang et al. “ Research progress on microbiological inhibition of corrosion: A review”, Journal of cleaner production, 373, 1 336658 (2022)
Magic-Angle Spinning NMR in a manganese sodium-ion cathode material and in surface-treated lithium titanate
No full textInternational audience1. AbstractHigh-resolution Magic Angle Spinning NMR can be performed on a wide variety of materials and providea wide range information on many atoms such as 6Li, 7Li or 23Na and correlation or relaxation experimentscan provide information on the localization of lithium or sodium ions and eventually probe phase separationin battery materials. [1,2]Moreover, in favorable systems such as lithium titanates, it has been shown that surface fluorination withXeF2 greatly improves the electrochemical properties. In such systems, high resolution MAS-NMR at highmagnetic field can help quantify the amount of fluorine in the structure, and the 19F chemical shift analysisyields information on the fluorine environment. Moreover, spin counting strategies based on HeteronuclearMultiple-Quantum Correlation experiments can provide the number of fluorine atoms which are coordinatedto lithium ions and help understand what kind of structures are created locally upon fluorination.[3]2. ExperimentalMost experiments on paramagnetic samples were realized at moderate magnetic field (4.7 T or 200 MHzfor 1H) with 1.3 mm rotor spinning around 60 kHz under N2 in Bruker spectrometers. For diamagneticsamples such as LTO, high magnetic fields (20 T or 850 MHz for 1H) provided a better signal-to-noise ratioand allowed spin counting experiments to be performed in 1.3 mm rotors.[1] B.Li, G.Rousse, L.Zhang, M.Avdeev, M.Deschamps, A.M.Abakumov, J.-M.Tarascon,Constructing “Li-rich Ni-rich” oxide cathodes for high-energy-density Li-ion batteriesEnergy Env. Sci. 16, 1210-1222 (2023)[2] Q.Wang, S.Mariyappan, G.Rousse, A.V.Morozov, B.Porcheron, A.Iadecola, R.Dedryvère, J.Wu, W.Yang,L.Zhang, M.Chakir, M.Deschamps, M.-L.Doublet, A.M.Abakumov, J.-M.TarasconUnlocking anionic redox activity in O3-type sodium 3d layered oxides via Li substitutionNat. Mater. 20, 353–361 (2021)[3] Y.Charles-Blin, D.Flahaut, J.B.Ledeuil, K.Guérin, M.Dubois, M.Deschamps, A.M.Perbost,L.Monconduit, H.Martinez, N.LouvainAtomic Layer Fluorination of the Li4Ti5O12 Surface: A Multiprobing SurveyACS Appl. Energy Mater. 2(9), 6681-6692 (2019
Trans‐Concerted Addition to Alkynes: the case of Ynamide Silylzincation
No full textInternational audienceAn original concerted antarafacial mechanism for the addition of diorganosilyl‐zinc reagents across the C–C triple bond in ynamides is computationally investigated using DFT calculations. This concerted mechanism, leading to a trans‐product in only one step, results in the formation of a Si–C and a Zn–C σ‐bonds on opposite sides of the π‐system. We demonstrate that the mechanism going through a η2‐vinyl intermediate and the proposal of a radical chain pathway are energetically unsustainable. The retained concerted antarafacial pathway is tested on experimental selectivities: the regioselectivity, in favor of the silyl β‐addition in ynamide, and stereoselectivity, which is cis‐ with (Me2PhSi)2Zn but trans‐ with [(Me3Si)3Si]2Zn, are well reproduced by DFT calculations. The regio‐ and stereoselectivity are discussed using the activation strain model and a chemical bonding analysis
Tensile and shear behavior of recycled AA 6060 aluminium chips by direct hot extrusion
No full textInternational audienceSolid state recycling of aluminium chips is a promising technique to reduce environmental impacts of secondary production. As the recycling process induces a highly oriented microstructure, this study aims to quantify the mechanical properties of extrudates and identify the role of chip boundaries in the fracture behavior. Tensile and shear tests are performed on heat treated AA 6060 alloy and analyzed using digital image correlation. The tensile behavior of the chip-based material is similar to its cast-based counterpart, reaching a yield strength of 230 MPa. Shear properties are close for small deformations, although the chip-based material have lower ductility due to the early onset of damage at the chip boundary. These results confirm the industrial relevance of this process for large scale recycling of aluminium
Lithium Diffusion‐Efficient Ionogels as Polymer Solid Electrolyte for Next‐Gen Lithium‐Ion Batteries
No full textInternational audienceThe search for safer next‐generation lithium‐ion batteries (LIBs) has driven significant research on non‐toxic, non‐flammable solid electrolytes. However, their electrochemical performance often falls short. This work presents a simple, one‐step photopolymerization process for synthesizing biphasic liquid–solid ionogel electrolytes using acrylic acid monomer and P 111i4 FSI ionic liquid. We investigated the impact of lithium salt concentration and temperature on ion diffusion, particularly lithium‐ion (Li + ) mobility, within these ionogels. Pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) revealed enhanced Li + diffusion in the acrylic acid (AA)‐based ionogels compared to their non‐confined ionic liquid counterparts. Remarkably, Li + diffusion remained favorable in the ionogels regardless of salt concentration. These AA‐based ionogels demonstrate very good ionic conductivity (>1 mS cm −1 at room temperature) and a wide electrochemical window (up to 5.3 V vs Li + /Li 0 ). These findings suggest significant promise for AA‐based ionogels as polymer solid electrolytes in future solid‐state battery applications
Spontaneous formation of polymeric nanoribbons in water driven by π‐π interactions
No full textInternational audienceA simple method was developed to produce polymeric nanoribbons and other nanostructures in water. This approach incorporates a perylene diimide (PDI) functionalized by hydrophilic triethylene glycol (TEG) as a hydrophobic supramolecular structure directing unit (SSDU) into the core of hydrophilic poly(N,N‐dimethylacrylamide) (PDMAc) chains using RAFT polymerization. All PDI‐functional polymers dissolved spontaneously in water, forming different nanostructures depending on the degree of polymerization (DPn): nanoribbons and nanocylinders for DPn = 14 and 22, and spheres for DPn > 50 as determined by cryo‐TEM and SAXS analyses. UV‐VIS absorption spectroscopy was used to monitor the evolution of the PDI absorption signal upon dissolution. In solid form, all polymers show a H‐aggregate absorption signature, but upon dissolution in water, the shortest DPn forming nanoribbons evolved to show HJ‐aggregate absorption signals. Over time, the J‐aggregate band increased in intensity, while cryo‐TEM monitoring evidenced an increase in the nanoribbon’s width. Heating the nanoribbons above 60 °C, triggered a morphological transition from nanoribbons to nanocylinders, due to the disappearance of J‐aggregates, while H‐aggregates were maintained. The study shows that the TEG‐PDI is a powerful SSDU to promote 2D or 1D self‐assembly of polymers depending on DPn through simple dissolution in water
Tailored functional monolayers made from mesoionic carbenes
No full textInternational audienceSignificant progress has been made over the last decades in surface functionalization of coinage metals using thiols and more recently N-heterocyclic carbenes. As shown in this work, mesoionic carbenes (MICs) provide straightforward access to a novel class of surface ligands including electroactive ones and thus materials. Importantly, MICs are easily accessed from triazolium salts (TS) onto which functional groups may be attached with little synthetic effort. Here, we present a library of TS that were further converted, in situ, into MICs and grafted onto gold surfaces. The modified surfaces were thoroughly characterized by advanced spectroscopic methods such as XPS, infrared and Tip-Enhanced Raman Spectroscopy. Through cyclic voltammetry at 100 Vs-1, we could evaluate the surfacic concentration of the grafted molecules for electroactive MICs. We also prepared mixed MIC/thiol self-assembled monolayers, which opens the route to multifunctional surfaces