I11-High Resolution Powder Diffraction
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Liam A. V.
Nagle-Cocco
,
Joshua D.
Bocarsly
,
Krishnakanth
Sada
,
Nicola D.
Kelly
,
Mathias A.
Kiefer
,
Emmanuelle
Suard
,
Sarah J.
Day
,
Cheng
Liu
,
Clare P.
Grey
,
Prabeer
Barpanda
,
Clemens
Ritter
,
Sian E.
Dutton
Diamond Proposal Number(s):
[33664, 28349]
Open Access
Abstract: Cryptomelane is a hollandite-like material consisting of K+ cations in an α-MnO2 tunnel-like crystallographic motif. Cryptomelane with stoichiometry KxMn8O16 (x ≈ 1.45) has been synthesized and its magnetic properties investigated using variable-temperature magnetic susceptibility, heat capacity, and neutron powder diffraction. Three distinct transitions at T1 = 184 K, T2 = 54.5 K, and T3 = 24 K are observed. At T1 there is a subtle tetragonal → monoclinic transition associated with emergence of a set of nonmagnetic superstructure peaks indexable to a
incommensurate modulation parallel to the α-MnO2 tunnels. Our findings are consistent with a relation previously reported in titanate hollandites, that
. Magnetic Bragg peaks emerge below T2 = 54.5 K, and their positions indicate an incommensurate modulated magnetic structure. The model consistent with the data is a dual-
structure with a ferromagnetic
component and an incommensurate
, with the latter most likely to be helical. The period of oscillation of the incommensurate magnetic component is in line with predictions based on a Heisenberg spin Hamiltonian [Mandal et al. Phys. Rev. B 2014, 90, 104420]. Below T3 = 24 K, there is a magnetic transition, which gives rise to a different set of magnetic Bragg peaks indicative of a highly complex magnetic structure.
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Oct 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[42410]
Open Access
Abstract: Photocatalytic reforming offers a route to valorize biomass and plastic waste into clean H2 under ambient conditions. However, the scalability of photocatalyst sheets is limited by high-temperature processing, binders and complex co-catalyst deposition. Here a [Co4Zr2O(OnPr)10(acac)4] single-source precursor is deposited onto Al-doped SrTiO3 and immobilized on glass substrates to fabricate photocatalyst sheets using multiple techniques, including high-throughput spray coating. The resulting sheets enable photoreforming of cellulose- and polyethylene terephthalate-derived feedstocks, producing H2 alongside value-added organics such as formate, acetate, glycolate and glycolaldehyde dimer. The system is demonstrated from the centimeter- to meter-squared scale, culminating in a 1-m2 outdoor reactor operating under natural sunlight. After 6 h, H2 yields reached 5.24 and 1.51 mmol m−2 for glucose and pretreated cellulose, respectively, with concurrent formation of oxygenates. Techno-economic analysis based on real-world data estimates an H2 cost of £0.93 mmol−1. This work advances scalable photocatalytic reforming and provides a step towards practical deployment.
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Jun 2026
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I11-High Resolution Powder Diffraction
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Heng
Wang
,
Rui
Wang
,
Christopher A.
O'Keefe
,
Erik
Bjorklund
,
Daniela
Proprentner
,
Joe C.
Stallard
,
Hwee Jien
Tan
,
Wesley M.
Dose
,
Louis F. J.
Piper
,
Robert S.
Weatherup
,
Angkur J. D.
Shaikeea
,
Clare P.
Grey
,
Michael
De Volder
Diamond Proposal Number(s):
[34243]
Open Access
Abstract: While electrochemical degradation mechanisms in lithium-ion batteries are well studied, the influence of mechanical factors remains poorly understood. Here we introduce a high-precision stack-pressure control and dilatometry tool to apply a uniform and constant stack pressure on electrodes independent of electrode swelling. By increasing stack pressure fourfold over typical initial values, we double the lifetime of graphite ‖ LiNi0.8Mn0.1Co0.1O2 cells, an industrially relevant battery chemistry, without altering active materials or electrolytes. This suggests that many lithium-ion batteries operate under sub-optimal stack-pressure conditions, leading to curtailed lifetimes. We demonstrate that different degradation mechanisms emerge outside the optimal pressure window: low stack pressure accelerates cathode cracking, whereas high pressure promotes lithium plating. Our findings highlight coupled mechanical–electrochemical degradation mechanisms and identify stack-pressure optimization as a practical solution for increasing cycling stability.
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Jun 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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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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James M. A.
Steele
,
Joshua D.
Bocarsly
,
Liam A. V.
Nagle-Cocco
,
George S.
Phillips
,
Farheen N.
Sayed
,
Giulio I.
Lampronti
,
Fabio
Orlandi
,
Pascal
Manuel
,
Iuliia
Mikulska
,
Clare P.
Grey
,
Sian E.
Dutton
Diamond Proposal Number(s):
[34243, 32018]
Open Access
Abstract: NaNiO2 is a promising cathode material for sodium-ion batteries due to its high theoretical capacity of 235.8 mAh.g–1. However, as with many Na-ion cathode materials, a series of poorly understood phase transitions occur on electrochemical cycling, inducing volume mismatch-based stress/strain, resulting in particle cracking, electrochemically disconnected particles and, therefore, irreversible capacity loss. This behavior is one key obstacle to developing long-lasting, high-performance Na-ion batteries. Although the series of phases that form as NaxNiO2 is electrochemically cycled have been previously identified, their structures remained unsolved, limiting our ability to understand and control the phase transition behavior. Here, we report structural solutions based on Rietveld refinement against high-resolution synchrotron x-ray diffraction (SXRD) and neutron powder diffraction (NPD) for the phases obtained on desodiation: P″3-Na1/2NiO2, O″3-Na2/5NiO2, and O‴3-Na1/3NiO2. Each phase contains a unique Na+/vacancy ordering, minimizing intralayer electrostatic repulsions between Na+ ions, and Nix+-charge ordering decreasing interlayer repulsions through the location of lower valence Nix+ nearer to vacancies. Using these structures, we conduct sequential Rietveld refinement against operando SXRD data, which supports prior identification of a transient P‴3-Na1/2<x<2/3NiO2 phase, not isolable ex situ. Operando data also identify the presence of a solid-solution phase O″3δ-Na1/3<x<2/5NiO2 and second-order behavior of the O″3-Na2/5NiO2 → O‴3-Na1/3NiO2 phase transition at the top of charge. This work provides unprecedented insight into structural evolution during electrochemical cycling in Ni-rich Na cathodes (and likely Li analogues), paving the way toward rational doping regimes designed to disrupt degradation-inducing phase transitions, increasing capacity and cycle lifetime, thus improving the performance of Co-free Na and Li cathodes.
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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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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[33172, 14239]
Open Access
Abstract: Recent reviews have highlighted borate polyanion systems as promising high-voltage cathode candidates for rechargeable Mg-ion batteries (RMBs) [Coordination Chemistry Reviews, 427, 213551 (2021)]. However, evaluating the electrochemical performance of cathodes for Mg-ion batteries is challenging, with many reports relying on an observed electrochemical capacity rather than demonstrating Mg-ion (de)intercalation. To address these two points, we study three classes of borate polyanions: orthoborates M3(BO3)2, ludwigites M3BO5, and pyroborates M2B2O5 and use a suite of experimental techniques to investigate de-magnesiation on charging vs Li metal with a Li electrolyte. We select five representative materials Mg2Mn(BO3)2, Mg2Ni(BO3)2, Mg2FeBO5, MgFeB2O5 and MgFe0.5Mn0.5B2O5. Whilst promising first charge capacities up to 200 mAh g−1 are observed for ball-milled cathodes cycled at 55°C in a Li containing electrolyte, extensive post-cycling analysis using ex-situ X-ray Photoelectron Spectroscopy (XPS) and ex-situ Synchrotron Powder X-ray Diffraction (SXRD), combined with operando X-ray Absorption Spectroscopy (XAS) and operando Online Electrochemical Mass Spectrometry (OEMS), show that the capacities obtained are not associated with Mg2+ mobility in the cathodes, de-magnesiation or transition-metal redox. The observed capacity originates from a process enhanced by ball-milling, which is common to all borate polyanions investigated in this work. This process is in part attributed to the irreversible reaction of an amorphous surface layer on the polycrystalline particle, rich in carbonate and glassy borate phases. Here we present the first systematic study of the viability of transition-metal borate polyanions as intercalation cathode materials for RMBs and conclude that, despite the promising electrochemistry, these materials do not de-magnesiate under our tested conditions.
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Sep 2025
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I11-High Resolution Powder Diffraction
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George S.
Phillips
,
James M. A.
Steele
,
Farheen N.
Sayed
,
Leonhard
Karger
,
Liam A. V.
Nagle-Cocco
,
Annalena R.
Genreith-Schriever
,
Gabriel E.
Perez
,
David A.
Keen
,
Jürgen
Janek
,
Torsten
Brezesinski
,
Joshua D.
Bocarsly
,
Sian E.
Dutton
,
Clare P.
Grey
Diamond Proposal Number(s):
[34243]
Open Access
Abstract: Lithium nickel oxide, LiNiO2 (LNO), and its doped derivatives are promising battery cathode materials with high gravimetric capacity and operating voltages. They are also of interest to the field of quantum magnetism due to the presumed S = 1/2 triangular lattice and associated geometric frustration. However, the tendency for Li/Ni substitutional defects and off-stoichiometry makes fundamental studies challenging. In particular, there is still a discrepancy between the rhombohedral (R3̅m) bulk structure and the Jahn–Teller (JT) distortions of the NiO6 octahedra inferred on the basis of local structural probes. Karger et al. (Chem. Mater. 2023, 35, 648–657) recently used Na/Li ion exchange to synthesize “defect-free” LNO by exploiting the absence of antisite disorder in NaNiO2 (NNO). Here we characterize the short- and long-range structure of this ion-exchanged material and observe splittings of key Bragg reflections at 100 K in X-ray and neutron diffraction (XRD and NPD), indicative of a monoclinic distortion induced by a cooperative collinear JT distortion, similar to that seen in NNO. Variable temperature XRD reveals a second-order phase transition from the monoclinic (C2/m) low-temperature structure to a rhombohedral (R3̅m) structure above ∼400 K. We propose that this collinear JT ordering is also present in solid-state synthesized LNO with the domain size and extent of monoclinic distortion controlled by defect concentration. This new structural description of LNO will help advance our understanding of its electronic and magnetic properties and the series of phase transformations that this material undergoes upon electrochemical cycling in Li-ion batteries.
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Jul 2025
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[28349]
Open Access
Abstract: An understanding of the nature of the grain boundaries and impurity phases contained in complex mixed metal oxide solid electrolytes is key to the development of improved and more stable solid-state batteries with reduced grain boundary resistances and higher ionic conductivities of the bulk sample. The Li-ion solid electrolyte Li7La3Zr2O12 (LLZO) is one of the most researched electrolytes in the field due to its high ionic conductivity, thermal stability, and wide voltage stability window. Despite its potential, the nature of the impurity and surface phases formed during the synthesis of LLZO and their role and influence on LLZO’s performance when used as an electrolyte remain poorly understood and controlled. In addition, there are limited characterization methods available for detailed studies of these impurity phases, particularly if these phases are buried in or close to the grain boundaries of a dense sintered material. Here, we demonstrate a solid-state nuclear magnetic resonance (ssNMR) and dynamic nuclear polarization (DNP) approach that exploits both endogenous and exogenous dopants to select for either specific impurities or separate bulk vs surface/subsurface phases. Specifically, the location of Al-containing phases within an Al doped LLZO and the impurity phases that form during synthesis are mapped: by doping LLZO with trace amounts of paramagnetic metal ions (Fe3+ and Gd3+), DNP is used to selectively probe Al- and La-containing impurity phases, respectively, allowing us to enhance the signals arising from the LiAlO2 and LaAlO3 impurities and to confirm their identity. A 17O DNP experiment using Gd3+ doped LLZO is performed to identify further La3+-containing impurities (specifically La2Zr2O7 and La2O3). Finally, a 7Li DNP irradiated 7Li–27Al dipolar-based heteronuclear multiple quantum correlation experiment is performed by using the radical TEKPol as the polarization agent. This experiment demonstrates that the poorly crystalline LiAlO2 that is found close to the surfaces of the LLZO composite is coated by a thin Li-containing impurity layer and thus not directly present at the surface.
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May 2025
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I11-High Resolution Powder Diffraction
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Jeremy P.
Lowen
,
Tharigopala V.
Beatriceveena
,
Joshua W.
Makepeace
,
Teresa
Insinna
,
Mark P.
Stockham
,
Bo
Dong
,
Sarah J,
Day
,
Clare P.
Grey
,
Emma
Kendrick
,
Peter R.
Slater
,
Paul A.
Anderson
Diamond Proposal Number(s):
[35016]
Open Access
Abstract: All-solid-state batteries utilising a Li-metal anode have long promised to be the next-generation of high-performance energy storage device, with a step-change in energy density, cycling stability and cell safety touted as potential advantages compared to conventional Li-ion battery cells. A key to enabling this technology is the development of solid-state electrolytes with the elusive combination of high ionic conductivity, wide electrochemical stability and the ability to form a conductive and stable interface with Li metal. Presently, oxide and sulfide-based materials, particularly garnet and argyrodite-type structures, have proved most promising for this application. However, these still suffer from a number of challenges, including resistive lithium metal interfaces, poor lithium dendrite suppression (at high current density) and low voltage stability. Here we report the first application of lithium imide, an antifluorite-structured material, as a solid electrolyte in a Li-metal battery. Low-temperature synthesis of lithium imide produces promising Li-ion conductivity, reaching > 1 mS cm-1 at 30 ˚C using a modest post-synthetic mechanochemical treatment, as well as displaying at least 5 V stability vs Li+/Li. In situ electrochemical operation of lithium imide with Li-metal electrodes reveals an apparent 1000-fold increase in its measured conductivity, whilst appearing to remain an electronic insulator. It is postulated that stoichiometry variation at the grain boundary may contribute to this conductivity improvement. Furthermore, the material is shown to possess impressive resistance to hard shorting under high current density conditions (70 mA cm-2) as well as the ability to operate in Li-metal battery cells. These results not only highlight the promising performance of lithium imide, but also its potential to be the basis for a new family of antifluorite based solid electrolytes.
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Apr 2025
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