I09-Surface and Interface Structural Analysis
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Galo J.
Paez Fajardo
,
Daniela E.
Dogaru
,
Hrishit
Banerjee
,
Muhammad
Ans
,
Matthew J. W.
Ogley
,
Veronika
Majherova
,
Gerard
Bree
,
Innes
Mcclelland
,
Shohei
Hayashida
,
Pascal
Puphal
,
Masahiko
Isobe
,
Bernhard
Keimer
,
Pardeep K.
Thakur
,
Tien-Lin
Lee
,
Dave C.
Grinter
,
Pilar
Ferrer
,
Serena A.
Cussen
,
Matthias
Hepting
,
Louis F. J.
Piper
Diamond Proposal Number(s):
[33459, 35075, 36917, 30201]
Open Access
Abstract: Describing lithium-based battery positive electrodes based on different transition metal or oxygen-redox regimes can cause confusion in understanding metal–ligand hybridization, oxygen dimerization and degradation processes. Therefore, it is urgent to investigate the electronic structure of these materials and identify the role each cation and anion has in charge compensation at the subnanoscale. Here, using X-ray resonance photoemission spectroscopy, single-impurity Anderson models, spectral simulations and theoretical calculations, we examine redox mechanisms in positive electrodes during lithium-based battery operation. This approach reconciles the redox description of two positive electrode active materials—LiMn0.6Fe0.4PO4 and LiNiO2—in terms of varying degrees of charge transfer using the Zaanen–Sawatzky–Allen framework. In LiMn0.6Fe0.4PO4, the lack of strong hybridization indicates that the capacity results from the depopulation of metal 3d states, that is, conventional metal redox. However, in cells with LiNiO2-based positive electrodes, negative charge transfer dominates, and redox occurs through the formation and elimination of ligand-hole states. These results clarify the role of oxygen in Ni-rich systems and provide a framework to explain how the charge/discharge capacities are linked to oxygen-dominated states in highly covalent systems, without the need to consider oxygen dimerization.
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Jun 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[37961]
Open Access
Abstract: In the present work, we report the exsolution of CoFe nanoalloy nanoparticles from Co and Fe co-doped lanthanum aluminate perovskite oxide, LaAl0.90Co0.05Fe0.05O3, and assess the perovskite oxide as an oxygen reduction reaction (ORR) electrocatalyst. We optimized both intrinsic and extrinsic material properties of perovskites to achieve good electrocatalytic performance in the kinetic and mass-transfer controlled region. Firstly, we demonstrated that the near surface segregation of B-site cation (Co) under reducing environment at low temperature (at 500 °C), believed to represent the initial stage of exsolution, led to high ORR activity in the mass-controlled region, with specific and mass activities of 4.9 mA/cm2 and 37.5 A/g (@0.4 V versus RHE), respectively. Secondly, reducing the particle size of perovskite oxide increased surface exposure to the reducing environment promoting the CoFe nanoalloy particle exsolution. The results demonstrate that cation enrichment in subsurface region, near grain boundaries contributes more effectively to ORR activity than exsolution in the form of nanoparticles in this perovskite oxide composition. Nevertheless, achieving fast charge transfer-kinetics without the use of precious metals still remains a challenge with lanthanum aluminates, as indicated by onset potentials of 0.84 V and 0.81 V (versus RHE) for the pristine and reduced perovskite oxide, respectively. Notably, impregnation of perovskite oxide with 0.2 wt. % Pt followed by heat treatment in reducing atmosphere at 500 °C increased the onset potential to 0.9 V. Overall, this study suggests that non-precious metal-doped lanthanum aluminate, LaAl0.90Co0.05Fe0.05O3, exhibits strong electrocatalytic activity and is further enhanced through impregnation treatment.
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Jun 2026
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Gaurav C.
Pandey
,
Ashok S.
Menon
,
Valeria
Calani San Miguel
,
José J.
Arroyo‐gómez
,
Harry
Gillions
,
Rebecca
Sellers
,
Matthew J. W.
Ogley
,
Eleni
Fiamegkou
,
Satish
Bolloju
,
Sahil
Tippireddy
,
Mirian
Garcia-Fernandez
,
Steven
Huband
,
Louis F. J.
Piper
Diamond Proposal Number(s):
[38432]
Open Access
Abstract: The electrochemical performance of single-crystalline (SC) Ni-rich layered oxide cathodes is fundamentally limited by bulk Li+ diffusion within micrometre-sized particles. During high-voltage cycling—necessary for high-energy applications—intraparticle Li+ diffusion is further impeded by oxygen-loss-induced surface reconstruction from the layered phase to spinel/rock-salt structures. Therefore, to fully understand how bulk Li+ transport kinetics influences electrochemical degradation, it is necessary to establish the correlation between surface reconstruction and bulk delithiation during the anisotropic structural evolution (i.e., expansion of the layers followed by their contraction) of the cathode particles during long-term cycling. In this work, we accomplish this using multi-rate operando X-ray diffraction studies of SC Ni-rich layered oxide cathodes aged under different voltage windows in single-layer pouch full cells. We quantify how increased surface reconstruction leads to greater heterogeneity in bulk delithiation, thereby promoting phase separation and exacerbating electrochemical capacity fade. These results provide a direct mechanistic link between surface degradation and bulk delithiation in such cathodes and offer a framework for non-destructively probing kinetics-dependent degradation under practically relevant conditions to guide strategies for improved cycling stability.
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May 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Understanding and tuning the local coordination environment of Fe−N4 macrocyclic catalysts are essential for advancing non-precious metal oxygen reduction reaction (ORR) electrocatalysis. Here, we present a comprehensive experimental and theoretical investigation of three structurally distinct Fe macrocycles, iron(tetraphenylporphyrin) chloride (FeTPP), iron(II) phthalocyanine (FePc), and iron aza-bridged bis-1,10-phenanthroline hexaaza-macrocycle (Fe(Phen2N2)), to unravel how bridging atom identity and coordination geometry impact ORR activity in alkaline media. These measurements identified FePc/CNT as the most active catalyst, followed closely by Fe(Phen2N2)/CNT, with FeTPP/CNT exhibiting the lowest performance. Density functional theory simulations further demonstrated that shorter Fe−N bonds and more electronegative bridging atoms correlate with weaker *OH adsorption and higher theoretical limiting potentials. Axial coordination can alter the adsorption energetics of ORR intermediates, thereby enhancing ORR activity. Together, these results highlight the critical influence on the ORR mechanism of macrocycle bridging atoms, coordination symmetry, and axial ligation, providing molecular-level insights to guide the rational design of Fe−N4 catalysts for alkaline fuel cell applications.
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May 2026
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DIAD-Dual Imaging and Diffraction Beamline
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[28349, 35126]
Abstract: Thick electrodes are a promising route to increase battery energy density by increasing the fraction of active material relative to inactive components. However, at high cycling rates, greater mass transport limitations in thick electrodes can lead to poor capacity utilisation and reduced power density. Although advanced electrode structuring strategies have been explored, many require expensive manufacturing changes or complex post-processing. An alternative approach uses standard battery manufacturing methods to sequentially coat active materials with different particle sizes or compositions. In this work, polycrystalline LiNi1/3Mn1/3Co1/3O2 (NMC111) particles of two sizes were used to fabricate particle size-graded bilayer electrodes. An impedance-based finite element model was developed to evaluate transport properties in the graded structures and was validated using electrochemical impedance spectroscopy (EIS) and rate tests. Operando synchrotron diffraction revealed a more homogeneous state of charge when smaller particles were positioned near the separator and larger particles near the current collector. Together, the modelling and experimental results show that simple particle size grading improves ion transport and reaction uniformity, enhancing capacity utilisation. This approach offers a practical pathway to improve the power performance of next-generation battery electrodes.
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May 2026
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[35312]
Abstract: Lithium batteries with enhanced energy density and safety require solid electrolytes having stability with High voltage cathodes and Li metal. Here, halide solid electrolyte Li3YCl6 is doped with Fluorine to simultaneously increase the cathodic and anodic stability. The anodic and cathodic stability was confirmed cyclic voltammetry, impedance spectroscopy and operando pressure measurement. Further, operando X-ray photoelectron spectroscopy (XPS) during Li plating on Li3YCl5.9F0.1 was done to study effect of Fluorine on reaction kinetics driving the evolution of interphase with Li metal and its composition. Li3YCl5.9F0.1 shows stable plating striping for more than 500 h and has very high critical current density of 8 mA/cm2. Li3YCl5.9F0.1 based ASSB operating at high voltage of 4.8 V vs Li maintains a high discharge capacity of 124 mAhg-1 at C/3 rate at room temperature after 180 cycles confirming excellent electrochemical performance. Further, Li3YCl5.9F0.1 as separator enable Li metal based ASSB.
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May 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[15151]
Open Access
Abstract: The development of efficient and durable electrocatalysts for the formic acid oxidation reaction (FAOR) is central to the progress of direct formic acid fuel cells (DFAFCs). Here, we investigate how the synthesis sequence and reduction pathway influence the surface and electronic structure of PdAgNi(OH)2/C nanocomposites and, consequently, their FAOR performance in acidic media. Binary Pd/Ni(OH)2 catalysts with Pd/Ni(OH)2 mass ratios of 30:70, 50:50, and 70:30 were first screened, revealing 50:50 as the optimal composition. Partial substitution of Pd by Ag (Pd40Ag10 and Pd30Ag20 on Ni(OH)2(50)/C) was then combined with either sequential or simultaneous NaBH4-assisted reduction. Structural characterization by XRD, TEM, and XANES/EXAFS show that simultaneous coreduction tightens the Pd–Ag–Ni interfacial coupling, enhances Pd dispersion, and increases the contribution of Pd–O and Pd–Ni scattering paths, indicative of strong metal–oxide interactions. Electrochemical measurements demonstrate that the Pd30Ag20Ni(OH)2(50)/C catalyst prepared by simultaneous reduction exhibits the highest mass activity toward FAOR (6164 mA mgPd–1), a ca. 23-fold enhancement over commercial Pd/C, together with improved stability under potential cycling. These results demonstrate that controlling the synthesis sequence is an effective method for tuning the interfacial electronic structure of multicomponent Pd-based catalysts, providing practical guidelines for designing FAOR electrocatalysts for DFAFCs and related liquid-fuel energy conversion devices.
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May 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34243]
Open Access
Abstract: A key challenge for incorporation of oxide-based solid electrolytes into batteries remains the brittle nature of the ceramic, which makes scalable, low-cost fabrication of thin (<20 µm) separators challenging. solution-based processing, involving the direct liquid-to-solid transformation of a precursor solution into a ceramic film through deposition and annealing, offers an attractive route to overcome these fabrication challenges while significantly reducing processing temperatures compared to conventional solid-state methods. However, the relationship between the initial choices made in precursor chemistries and the crystallization behavior remains poorly understood, limiting control over the phase formation process. Here, we investigate how the precursor decompositions influence the structure evolution during annealing and crystallization of solution-processed Li-garnet solid electrolyte films. The results reveal a sequence of solvent and precursor decompositions with the Li-precursor, LiNO3, decomposition occurring last and in parallel with the nucleation of La2Zr2O7 as the first crystalline metal-oxide phase. Upon Li-precursor decomposition, the latter is lithiated to form the desired highly conductive cubic Li6.25Al0.25La3Zr2O12 phase. This simultaneity of crystallization and decomposition events demonstrates the importance of the initial precursor choices to control the crystallization process. Through this work, we contribute to fundamental ceramic materials science by establishing a systematic methodology for studying solution-processing and providing a foundation for future precursor design of next-generation solid electrolyte battery components.
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May 2026
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
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Ainara
Aguadero
,
Federico
Baiutti
,
Monica
Burriel
,
Markus
Kubicek
,
Alexander Karl
Opitz
,
Juergen
Fleig
,
David
Munoz-Rojas
,
Christophe
Vallée
,
Marceline
Bonvalot
,
Alexia
Popescu
,
Nicola H
Perry
,
Francesco M.
Chiabrera
,
Álex
Morata
,
Juan Carlos
Gonzalez-Rosillo
,
Alexander
Stangl
,
Ramon
Escobar-Galindo
,
Mattias
Krause
,
Sivakkumaran
Sukumaran
,
Sarah
Fearn
,
Richard J.
Chater
,
Stephen J.
Skinner
,
John
Kilner
,
Sören
Möller
,
Martin
Finsterbusch
,
Manoj Kumar
Ghosalya
,
Samuli
Urpelainen
,
Christoph
Baeumer
,
Santosh
Kumar
,
Veronica
Celorrio
,
Diego
Gianolio
,
David C.
Grinter
,
Pilar
Ferrer-Escorihuela
,
Georg
Held
,
Jordi
Cabana
,
Sandrine
Lyonnard
,
Dorthe
Bomholdt Ravnsbaek
,
M. Rosa
Palacin
,
Montserrat
Casas-Cabanas
,
Julie
Villanova
,
Aline
Léon
,
Qiucheng
Xu
,
Jakub
Drnec
,
Brian
Seger
,
David R
Diercks
,
Nejc
Hodnik
,
Lluís
Yedra
,
Sonia
Estrade
,
Francesca
Peiró
,
Neus
Domingo
,
Maciej O
Liedke
,
Enric
Menéndez
,
David J.
Keeble
,
Jakub
Čížek
,
Ralf F.
Ziesche
,
Oriol
Sans Planell
,
Nikolay
Kardjilov
,
Ingo
Manke
,
Daniele
Pergolesi
,
Jochen
Stahn
Open Access
Abstract: A strong societal and political drive is motivating the development and optimization of novel
energy
conversion and storage systems for decarbonization. The successful implementation of solid
state devices such as fuel cells and secondary batteries depends, however, on achieving
ambitious targets in terms of performance, reliability and cost competitiveness. Research and
technology are addressing these needs through a holistic approach including exploration of new
materials and nanoarchitectures, as well as system engineering. These significant efforts require
the support of appropriate characterization tools capable of assessing nanometer-scale
phenomena such as concentration profiles of ionic and electronic charges, local chemical
compositions and their evolution over time across interfaces.
This roadmap provides an overview of selected advanced characterization techniques for
energy materials and devices. Specific focus is put on in situ/operando methods for probing
electrochemical phenomena in real-time under realistic working conditions. Experts in the field
provide an extensive review of the current state of the art in 2025 and the current and future
challenges for the characterization of local chemistry and kinetics in the bulk of the material, in
nanoarchitectures (e.g. thin films) and at the interfaces (e.g. grain boundaries, phase contacts,
solid/liquid and solid/gas interfaces) . The aim is to provide a detailed guide to the techniques,
describing opportunities and bottlenecks for their practical deployment and examples of
successful
applications.
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May 2026
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I11-High Resolution Powder Diffraction
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Open Access
Abstract: Polymorphism plays a critical role in determining the performance of bio-derived phase-change materials (PCMs). In this work, we investigate the polymorphism of methyl behenate, a fatty acid ester with potential for sustainable phase-change material for thermal energy storage. Three previously unknown polymorphs were identified, and their thermophysical properties were characterised by differential scanning calorimetry and hot-stage microscopy, highlighting the strong influence of polymorphism on the material properties. The structure of two polymorphs were determined using laboratory and synchrotron powder X-ray diffraction. The comparison with a related fatty acid ester reveals common structural trends, suggesting emerging structure–property relationships within this class of materials. These results provide new insights into ester-based PCMs and support the rational design of sustainable thermal energy storage materials.
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May 2026
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