InCAEM will develop a singular infrastructure open to all the scientific community for research in advanced energy materials in order to address the scientific challenges of the European Green Deal. The project started in October 2022 and will have the infrastructure ready by end of 2025. It includes new equipment, infrastructure and staff.

New instruments to be installed in the ALBA premises are a high resolution (scanning) transmission electron microscope for in situ studies in gas and liquid environments and a scanning probe microscopies platform including tip-enhanced Raman spectroscopy capabilities and flexible sample environments. Advanced data infrastructures will be installed both at ALBA and at PIC-IFAE for in situ and ex situ data processing, respectively. In addition, we will carry out the adaptation of existing beamlines to perform correlative experiments, and develop methods and pipelines for multi-modal approaches.

Compatible operando sample environments for complementary characterization tools together with advanced data analysis will provide excellent opportunities for true multi-modal and multi-length scale characterization of functional materials aimed at developing new sustainable materials to be used in batteries, electric vehicles or solar cells, among others. While (S)TEM and scanning probe microscopies offer unsurpassed spatial resolution and a variety of contrast mechanisms, X-ray-based techniques provide highly specific chemical, structural, electronic and magnetic information with high efficiency so that larger fields of view, thicker samples and faster processes can be studied.

The possibility to perform experiments in situ during relevant processes such as reactions, sample growth, thermal treatment or electrochemical cycles, and the correlation of results from different instruments with identical experimental conditions will permit linking the structural, compositional and morphological aspects of the same (nano)structures and of their surroundings for a comprehensive understanding of their structure-function relationship.

We will present the project and the opportunities it will bring for the user community with the help of selected application examples.

Battery technology has become increasingly important in recent years due to the growing demand for portable electronic devices and electric vehicles, and to improve the performance and lifespan of batteries it is essential to understand the complex processes that occur during their operation. NOTOS is a beamline from ALBA Synchrotron Light Source devoted to X-ray Absorption Spectroscopy (XAS), X-Ray Diffraction (XRD) which has been designed to study the electronic structure and the short- and long-range order in a wide range of scientific disciplines: chemistry, catalysis/electrocatalysis, energy science, nanomaterials, condensed matter, and environmental science. The available energy range is now 4.5-30 keV and the photon source is a bending magnet, but it will be extended up to 35 keV thanks to a partial refurbishment of the optics and the change of the bending magnet with a SuperBend source in the framework of the ALBA-II upgrade. In addition to the capability to perform XAS and XRD investigations separately, the beamline allows quasi-simultaneous XAS-XRD experiments. Examples of XAS and XRD measurements on commercial electrodes (phospho-olivine LiFePO4 and NMC111) are presented showing the performances of the beamline in operando. Finally, as real research case, we discuss the structural stability of Bimetallic Cu-doped Gold Nanoclusters in electrochemical CO2 reduction. 

The characterization of the electronic structure of nanomaterials, ideally in operando in an electrolyte, is essential for electrochemical applications such as in energy storage and conversion. To this aim, soft X-ray spectroscopies are particularly relevant as they enable the selective characterization of either the electrolyte or the material of interest thanks to their element specificity.¹ Furthermore, the high chemical sensitivity of X-ray absorption spectroscopy coupled to the high spatial resolution (<30 nm) offered by soft X-ray spectromicroscopy enables the chemical imaging of nanomaterials, which can provide precious information about local inhomogeneities at the nanoscale.² In this talk, I will introduce synchrotron-based in situ soft X-ray spectromicroscopy techniques and explain how they can be applied to investigate carbon nanomaterials. A special emphasis will be provided on in situ cells allowing characterization under controlled atmosphere or in liquid in the soft X-ray range. These techniques will be illustrated by our recent work on the characterization of two class of nanomaterials: (i) nanoporous carbon materials in which the addition of nitrogen can modify the interaction with water molecules,³ and (ii) 2D titanium carbides MXenes, for which the chemical bonding between the Ti and C atoms remains poorly investigated. The role of hydration will be particularly discussed along future perspectives of X-ray spectromicroscopy.

We have developed new environmental liquid cells for Hard X-ray Photoelectron Spectroscopy (HAXPES) experiments at the HAXPES endstation of the GALAXIES beamline at the SOLEIL synchrotron radiation facility using on-purpose designed thin (15-25 nm) low-stress silicon nitride membranes. The membranes were fabricated at IMB-CNM-CSIC from 100 mm silicon wafers using standard lithography techniques and in order to facilitate fast positioning of the X-ray beam on the membrane, platinum alignment marks have been added to the chips hosting the membranes. We have selected rectangular membranes in order to achieve an optimal balance between producing large enough membranes ensuring mechanical stability as well as conforming to the elliptical shape of the synchrotron radiation beam, about 30 µm (V) × 100 µm (H), since in this configuration the strain depends mainly on the short dimension of the rectangle. Optimizing such dimensions, we have fabricated membranes with dimensions of about 20-90 um (V) x 530-600 um (H). The geometry of the HAXPES endstation, with horizontal polarization parallel to the analyzer axis and the intrinsic 54.7 degrees angle arising from the chemical etching of silicon for the fabrication of the membranes, imposes incidence angles of about 45 degrees.

Two types of liquid cells have been built: (i) a static one mounted on an Omicron-type sample holder with the liquid confined in the cell container, and (ii) a circulating liquid cell, inspired on an existing electrochemical cell installed at the LUCIA beamline [1]. The cells have been successfully tested in first exploratory experiments with aqueous solutions of salts (Na⁺, Cs²⁺, Cl^-), with dispersions of gold nanoparticles and in electrochemical experiments using a coin-cell configuration [2]. The membranes are mechanically robust and withstand the 1 bar pressure difference between the liquid inside the cell and vacuum and the intense synchrotron radiation beam during data acquisition if correctly handled. The lifetime of the membranes is beyond the time scale of the performed experiments in our tests (more than 6 hours). Our results open the door to regular HAXPES studies of liquids under circulation and potentially to other techniques using synchrotron radiation such as e. g., X-ray absorption and transmission.

In-situ techniques are key to elucidate the structure of the electrochemical interface, the active sites, and the reaction mechanisms of electrocatalytic reactions for sustainable energy conversion and storage. This talk will focus on the combination of electrochemical methods and different in-situ and operando surface-sensitive techniques including vibrational spectroscopy and synchrotron-based characterisation to understand and tune the structure-activity and structure-selectivity relationships for different electrocatalytic reactions of interest to produce renewable fuels and chemicals. These reactions include oxygen electrocatalysis for green hydrogen production and utilisation and the electrosynthesis of green fuels and value-added chemicals using electrochemical carbon dioxide, nitrate, and methane conversion.

First, I will present our work toward understanding and tuning the structure-activity relations on well-defined Pt-based surfaces for oxygen electrocatalysis by combining electrochemical methods, ex-situ surface science characterisation and in-situ grazing incidence X-ray diffraction [1,2]. Then, I will show our model studies on well-defined Cu-based electrocatalysts to assess the interfacial properties of the electrochemical CO2 and CO reduction reactions [3]. We have investigated new methods to evaluate and tailor the facet distribution on Cu-based catalysts [4]. Finally, I will discuss some approaches toward the in-situ investigations of the reaction mechanisms for the electrochemical nitrate reduction to produce ammonia and the co-reduction of CO2 and nitrates to produce sustainable fertilisers such as urea.

Copper-based nanostructures are active catalysts for the electrochemical reduction of CO₂ (CO₂RR) to energy-rich products, with morphology often correlated to the catalytic performance. This study investigates the synthesis, structural evolution, and catalytic behaviour of Cu₂O nanoparticles (NPs), integrating morphological control with electronic structure analysis to reveal the true role of morphology in CO₂RR. At the university of Salford, we have developed a surfactant-free synthesis method, which produces Cu₂O NPs with tuneable shapes, including sharp-edged nanocubes (NCs) and novel popcorn-like morphologies (nano-popcorns, NPCs), under varying pH and atmospheric conditions. In-situ techniques, such as X-ray absorption fine structure (XAFS) and UV-Vis spectroscopy, capture the dynamic interplay of dissolution and condensation equilibria, shedding light on the evolving chemical speciation of Cu during nanoparticle formation.

In-situ electrochemical liquid scanning transmission electron microscopy (EC-LSTEM) at Freiburg University, in collaboration with the group of Anna Fischer, has revealed distinct dynamic behaviours of the particles under CO₂RR, depending on their starting morphology. Herein, I will establish parallels between the chemistry involved during synthesis as a function of macroscopic parameters, as revealed by in-situ and ex-situ XAFS and TEM analysis, and the behaviour of the particles under CO₂RR. By bridging these observations, I aim to explain how the particle morphology evolution during CO₂RR is linked to the electronic structure of the electrocatalysts, and how these changes explain catalytic selectivity and stability.

Molecular electrochemistry has been complemented for several decades by spectroscopic measurements performed under in situ conditions, a method known as spectroelectrochemistry. Several spectroscopic techniques have been used in this configuration to provide structural insight in the understanding of molecular reactions mechanisms. In this talk, we will present how X-ray absorption spectroscopy, a synchrotron-based technique, can be instrumental in determining the local and electronic structure of electrochemically generated molecular species.

We will focus on the particular case of iron porphyrins, which are very efficient catalysts for the electrochemical reduction of CO₂ into CO.¹ We will first present a spectroelectrochemical cell specifically designed for the study of homogeneous molecular species generated electrochemically, together with a dedicated chamber for X-ray spectroscopic experiments. We will then present and analyze the X-ray absorption spectra collected on the starting Fe(III) species and its counterparts reduced by one, two or three electrons. Comparing the data collected under argon or CO₂ will provide clues on the interactions between this substrate and the metal center, as well as on the CO₂ reduction mechanism.² Finally, we will discuss the possibility to perform similar experiments with time-resolution on electrochemically generated molecular species.

In the last decades, copper has attracted considerable attention over other pure metal catalysts for its exceptional performance in the electrocatalytic reduction of CO₂ into valuable hydrocarbons and alcohols [1]. However, the selectivity of this reaction remains a key challenge for industrial applications. It is well-established that the selectivity is influenced by the oxidation state of the catalytic material [2], highlighting the importance of understanding and controlling the dynamics of electronic properties at the solid/liquid interface during CO₂ reduction reaction (CO₂RR). In-situ / operando spectroscopic techniques, such as X-ray absorption (XAS), are essential as they can provide important information about the chemical state of the elements of interest, though it is technically challenging in the soft X-ray regime.

To overcome these limitations, a strategy increasingly adopted to study solid/liquid interfaces under ultra-high vacuum conditions involves using electrochemical cells equipped with X-ray transparent Si₃N₄ membranes. These membranes allow the separation of the liquid phase from the vacuum while enabling X-ray spectroscopy. Such cells facilitate the investigation of changes in the oxidation state of catalytic material during electrochemical reaction by measuring XAS spectra at the core level edges, typically using total fluoresce yield (TFY) mode.

This strategy has been successfully implemented at BACH beamline, in collaboration with the technical service group of IOM-CNR [3]. The microfluidic electrochemical cell (ME-cell) features inlet and outlet channels, which allow for the renewal of the electrolyte, and a three-electrode system, comprising an Ag/AgCl leakless as reference electrode (RE), a Pt wire as counter electrode (CE) and a working electrode (WE) made of an Au-coated Si₃N₄ membrane onto which the catalytic material is deposited.

Stability studies of electrodeposited copper nanoparticles (CuNPs) were carried out in alkaline media, where dissolution and re-deposition phenomena were observed. Our results revealed that electrodeposited CuNPs on graphene substrates present higher stability after re-deposition, showing to be a more promising catalyst for CO2RR. Additionally, a significant effect on the chemical state of pristine CuNPs was identified after incorporating the well-known Nafion polymer as a binder. In-situ XAS measurements demonstrated that Nafion induces a persistent copper (II) oxidation state under near-catalytic conditions during CO₂RR, which disappears after the first cycle of activation, suggesting a dynamic transformation of the catalytic surface. Furthermore, in collaboration with the University of Trieste, we observed that the Nafion deposition methodology (e.g., spin coating vs. drop-casting) impacts the product selectivity during the reduction mechanism of CO2.

Our results emphasize the importance of in situ XAS measurements to understand the stability of copper-based catalysts in alkaline media. Moreover our results highlight the critical role of polymer incorporation in tailoring the performance of Cu-based catalysts for CO2 reduction reaction.

The electrolytic splitting of water into its elements is Reaction No.1 in modern electrochemistry. Discovered by van Troostwijk, Nicolson, Carlisle, and Ritter, water splitting and its half-cell constituents - hydrogen evolution (HER) and oxygen evolution (OER) – later became the most widely explored electrochemical model reactions in ground-breaking works by Bockris, Parsons, Conway, and Gerischer. Over the past 2 decades, advanced characterization methods coupled to high performance computations have offered new molecular insights into the reactive interface of catalyst and electrolyte. Today, water splitting using renewable power is an emerging industrial process technology to generate “green” hydrogen, a versatile energy vector for the decarbonization of power generation, heat, mobility, and industry.

In this presentation, I will share some of our recent work on the design and ex/in-situ characterization of electrocatalytic materials, interfaces and mechanisms for the electrochemical oxygen evolution reaction (OER). Catalytic materials such as Iridium oxide and Nickel oxides along with similarities and differences in their mechanisms in acid and alkaline environments will be discussed.

Transport electrification has resulted in an expansion of the Li-ion battery application from Wh to kWh storage. This has brought up additional requirements to improve performance (e.g. power, cycle life) enhance of sustainability and decrease of cost. Blending different active materials at the same cell electrode, an empirical approach commonly used for primary cells, has been readily applied to commercial EV Li-ion batteries mostly on the positive side. The global aim is to promote positive synergetic effects between the different electrode components, which have unfortunately received limited attention at the fundamental research level.

Materials with fast reaction kinetics, such as LiMn₂O₄ (LMO) can sustain significantly higher effective rates than the nominal rate applied to the electrode. This has motivated the widespread commercial use of NMC:LMO blends as LiNi_xMn_yCo_zO₂ (x+y+z=1, NMC) despite having slow kinetics, exhibits high capacity (especially for large amounts of Ni) and the addition of LMO lowers overall costs while enhancing power performance. Olivine LiMPO₄ (M=Fe, Mn) based blends have a lower presence in commercial cells to date but they have also deserved attention at the laboratory scale as they can as well exhibit fast kinetics and are based on low cost abundant transition metals.

Results will be presented related to different blends, consisting of combinations of LMO, NMC, LiFePO₄ (LFP) and LiFe_0.35Mn_0.65PO₄ (LFMP). Electrochemical experiments coupled to time-resolved synchrotron operando X-ray diffraction experiments enable to capture charge transfer events between blend components which are dependent on both voltage profile and kinetics of individual blend components. The results demonstrate the significant impact of the voltage profiles of individual materials on the current distribution, with the effective C-rate of each component varying throughout the state of charge (SoC).

Finally, systematic operando synchrotron X-ray diffraction and absorption experiments will be presented for NMC and LFP with diverse experimental conditions (cell type, radiation energy etc.) to illustrate the existence of beam-induced effects which may bias interpretation of results. These range from total reaction inhibition to partial hindrance and negligible deviations from the expected mechanism, and have been consistently observed across various experimental conditions, photon energies, photon fluxes and exposure times. The total radiation dose per cycle seems to be a useful predictor of the magnitude of beam-induced electrochemical delay and could serve as a guideline to define reliable measurement protocols.

Thanks to the operating high voltages and delivered capacities, Li-rich transition metal (TM) oxide cathodes are among the most promising materials for next-generation lithium-ion-batteries, where Co-free Li-rich cathodes join reduced costs with competitive performances. However, their cycle-life remains limited, and the individual role of TMs is still not fully understood. The investigation of the TM chemical species evolution along the first charge for the Li_1.2Mn_0.56Ni_0.16Co_0.08O₂ and Li_1.2Mn_0.6Ni_0.2O₂ systems have been accessed by means of operando multi-edge XAS. The charge compensation mechanism has been studied and the effect induced by removing Co has been revealed. Statistical data analysis methods reveal that the absence of Co results to accelerate and complete the Ni oxidation along the first charge and to inhibit the undesired spinel formation and oxygen release at the end of the first voltage plateau. The reasons of the oxygen release in the Co-containing electrode and its relation to structural modifications will be presented.

Aqueous Zn-MnO₂ batteries with mildly acidic electrolytes are a promising alternative to Li-ion batteries for large-scale energy storage due to their low cost and high safety and still remarkable energy density. These advantages arise from the high capacity of the Zn metal anode and its potential allowing plating in aqueous electrolytes. Zn is in addition widespread, cost-effective and easily recyclable. Among possible cathode materials, MnO₂ stands out due to its abundance, environmental advantages, and long-standing use, in Zn/MnO₂ alkaline batteries. The demonstration of rechargeability in mildly acidic electrolytes has expanded its potential for energy storage.

Despite their promise, the mechanism of mildly acidic Zn/ MnO₂ batteries is complex and remains debated. Early studies ruled out Zn²⁺ intercalation, instead suggesting proton intercalation or a dissolution-precipitation process involving MnO₂ dissolving into Mn²⁺ and the simultaneous formation of Zinc Hydroxide Sulfate (ZHS, ZnSO₄[Zn(OH₂)]₃·xH₂O) during discharge. This dissolution-precipitation mechanism, capable of a two-electron transfer, offers a higher theoretical capacity compared to intercalation. However, practical capacities are often closer to those of a one-electron process. Furthermore, during charging, the process is not simply reversed; the electrochemical profile reveals distinct stages, including at least two plateaus and a pseudocapacitive region, indicating a more intricate mechanism. Similar multistage profiles are observed in subsequent discharges.

Clarifying the overall reaction mechanism and the factors limiting practical capacity is challenging due to the poorly crystalline nature of many involved Mn compounds, often hygroscopic, which limits structural information from diffraction and ex-situ studies.

X-ray absorption (XAS), which is capable of detecting bulk speciation of most elements regardless of crystalline state even when embedded in heterogeneous matrix is therefore a very powerful technique for such investigation, and we applied it in several different modalities. We studied the mechanism by operando XAS at the Mn and Zn K-edges to follow speciation simultaneously and quantitatively in the cathode and in the electrolyte, essentially confirming the nowadays mostly accepted dissolution/deposition mechanism, however showing some deviations in the ZHS formation rate, and quantifying parasitic H₂ evolution reaction.  In addition, the significant evolution of the absorption fine structure region (EXAFS) of the Mn K-edge suggested existence of Mn(III) intermediate. Further evidence of Mn(III) was provided by soft X-ray microscopy, providing access to the Mn-L edge with higher sensitivity to the oxidation state. Operando conditions were in this case consistent with more detailed ex-situ data. Finally, magnetic moment derived from Mn K_β X-ray emission also confirm presence of Mn(III). Principal component analysis suggests that actually several kinds of reduced Mn species do exist, which can be associated with MnO₂ initial defects, reaction intermediates and newly formed species.

The complementarity of operando and ex-situ techniques and the beam effects present in this system will be also discussed. Overall, such pieces of information provide a more complete overview of the reaction complexity. Nonetheless, understanding these processes is key to optimizing Zn-MnO2 batteries for large-scale, sustainable energy storage applications.

Redox Flow Batteries (RFBs) are among the most promising and innovative solutions to face the intermittency issues come from the renewable energy. Specifically, their peculiar design physically separates the power-generating stack from the energy capacity stored in the electrolyte. This feature allows for flexibility, modularity, and easy upgrades according with the necessity/application. Indeed, the RFBs can be designed from kW to MW with sufficient extended duration (> 10 hours), assessing superior safety in comparison with Li-ion batteries.

Nowadays, Vanadium Redox Flow Batteries (VRFB) dominates the market, thought their widespread application is hindered for economic, low energy/power density values and sustainability drawbacks. In this fashion, an emerging strategy from scientific community is the replacement of the vanadium by water-soluble molecules. Herein, polyoxometalates (POMs) offer exceptional advantages, enabling unusual capability to accept/donor a large number of electrons under reversible and stable manner. Additionally, their solubility in water is remarkable and the synthesis process is quite straightforward and suitable for large production.

Herein, the POM based on K₆[Fe₄(H₂O)₂(PW₉O₃₄)₂]·20H₂O (hereafter Fe4(PW9)2) has been demonstrated for the first time in RFB as redox active specie for the negative half-cell. The synthesis of Fe4(PW9)2 has been carried out following the steps published previously [1]. After that, the POM was stabilized in a buffer electrolyte at pH 5, using 1 M concentration of (lithium acetate and acetic acid) as supporting electrolyte. This POM is able to transfer up to 10 e-, operating at low potentials (ca. to -1 V vs Ag/AgCl) with excellent reversibility. Particularly, the Fe³⁺/Fe²⁺ redox processes appeared between 0 to 0.2V vs Ag/AgCl, involving 4 electrons; and the W⁵⁺/W⁶⁺ redox processes started below -0.5 V vs Ag/AgCl, comprising two plateaus of 3 electrons each one, the second one limited by competing H2 evolution, and possibly involving structural rearrangements affecting the corresponding oxidation potential. The long-term stability of the Fe4(PW9)2 operating in the protentional range between -0.5 to -1 vs. Ag/AgCl has been demonstrated, showing the feasibility of the Fe4(PW9)2 electrolyte operates up to 44 h achieving excellent reversibility. Finally, in operando measurements using X-ray absorption/fluorescence radiation with the individual monitoring of the Fe K-edge and W L-edge energies confirm the dynamic structure, reversibility and oxidation states at several current densities applied.