B18-Core EXAFS
|
Abstract: Dual-atom catalysts (DACs) surpass the limitations of single-atom catalysts by harnessing synergy between adjacent metal sites. Herein, we propose a novel strategy employing d-p orbital synergistic modulation in Fe-Sb DACs. Combined density functional theory and molecular dynamics simulations reveal that the significant d-p orbital synergistic regulation between Fe and Sb sites promotes O2 adsorption and activation, lowers the energy barrier for Osingle bondO bond cleavage, and optimizes water desorption. As a proof-of-concept, Fe/Sb DACs anchored on a nitrogen-doped carbon matrix (Fe/Sb-N-C) were synthesized. The atomic-level local coordination of Fe-Sb dual atoms was systematically characterized by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) analyses. The as-fabricated Fe/Sb-N-C exhibits exceptional alkaline oxygen reduction reaction (ORR) performance, featuring a half-wave potential of 0.92 V and outstanding durability. Aqueous Zn-air batteries equipped with Fe/Sb-N-C achieve a high maximum power density of 196 mW cm-2 and a specific capacity of 795 mAh g-1. Furthermore, quasi-solid-state Zn-air batteries demonstrate wide-temperature operability (-30 to 60 °C) and stability under high current densities. This work establishes d-p orbital synergy as a new paradigm for designing high-efficiency ORR catalysts, broadening their application in energy devices across extreme temperatures.
|
Sep 2026
|
|
E01-JEM ARM 200CF
|
Jianan
He
,
Adrian Chun Minh
Loy
,
Jining
Guo
,
Ali
Zavabeti
,
Lei
Dong
,
Jia Ming
Goh
,
Chao
Wu
,
Dingqi
Wang
,
Qining
Fan
,
Caiden J.
Parker
,
Martin J.
Taylor
,
Jitraporn
Vongsvivut
,
Longbing
Qu
,
Joshua D.
Butson
,
Gang Kevin
Li
,
Qinfen
Gu
Diamond Proposal Number(s):
[42384]
Abstract: The hydrogen evolution reaction (HER) exhibits pH- and electrolyte-dependent pathways, imposing intrinsic challenges on the development of catalysts that operate efficiently across wide pH conditions and in seawater electrolysis. Here, we report a dual-single-atom catalyst with proximate cooperative Pt and Ni sites on a MXene (Ti3C2Tx) platform that enables synergistic optimization of HER elementary steps. A one-step molten salt-assisted strategy, free of F-based chemicals, allows the construction of high-density, well-dispersed Pt and Ni single atoms on MXene with well-defined coordination environments. Atomic-resolution microscopy and x-ray absorption spectroscopy confirm the stabilization of isolated Pt and Ni sites, while in situ synchrotron-based FTIR and DFT calculations reveal that proximate Ni sites modulate the electronic structure of Pt, weakening hydrogen adsorption and promoting water dissociation. As a result, the PtSAsNiSAs/Ti3C2Tx delivers low overpotentials of 22.6 and 59.1 mV at 100 mA cm−2 in acidic and alkaline electrolytes, respectively, and maintains high activity in neutral electrolyte (282 mV) and alkaline seawater (73.2 mV) with stability up to 100 h, outperforming commercial 20% Pt/C. These findings demonstrate that leveraging the intrinsic surface chemistry of MXenes enables cooperative dual-single-atom architectures with synergistically optimized HER pathways, driven by inter-site electronic coupling across diverse pH conditions.
|
Aug 2026
|
|
I22-Small angle scattering & Diffraction
|
Diamond Proposal Number(s):
[30847, 26958]
Open Access
Abstract: Amphiphilic polymer conetworks (APCNs) are thin, flexible and breathable matrices with a heterogeneous nano-phase separated morphology, making them ideal candidates for applications such as wearable luminescent solar concentrators (LSCs) for sunlight harvesting. Such materials should possess a well-defined morphology, with domains at the nanoscale that allow the incorporation of luminophores at specific volumes. This improves the efficiency of Förster resonance energy transfer, a feature essential for state-of-the-art LSC systems. Although APCNs have been developed and investigated extensively over recent decades for different applications, we now focus on the specificities of using APCNs for LSCs, and how it influences the design process. We found that the phase ratio of an APCN strongly affects its transition temperature and hence, the extent of its influence on the mechanical properties at room temperature. Similarly, although the chemistry of the hydrophobic domain influences the mechanical properties, the extent of these changes depends on the molecular weights of the precursors. We also demonstrated that Dynamic Mechanical Thermal Analysis (DMTA) a suitable alternative method of investigate in the morphology and phase separation in APCNs for which the phase contrast is too low for small- angle neutron scattering (SANS) and small- angle X-ray scattering (SAXS). In-situ strain SAXS measurements indicated that the macroscopic deformation is reflected at the deformation of the nanoscale domains. Taken together, these results help to design APCNs with tunable morphologies and mechanical properties and suggest alternative characterization methods, which contribute to revealing the full property space of APCNs for applications in energy harvesting and beyond.
|
Aug 2026
|
|
I11-High Resolution Powder Diffraction
|
Diamond Proposal Number(s):
[36397]
Open Access
Abstract: A detailed understanding of solid-state reaction pathways is essential for connecting predictive frameworks, such as density functional theory and machine learning, with experimental synthesis. Microwave synthesis has emerged as a powerful route for preparing inorganic materials, yet the mechanisms governing microwave-driven processes remain poorly understood, particularly for metastable compounds whose formation is highly sensitive to synthesis conditions. Disordered rocksalt oxides (DRX) are high-temperature metastable phases of interest as next-generation Li-ion cathodes. Here, we investigate the microwave reaction pathway of mathematical equation. Combining ex situ phase identification using x-ray diffraction and solid-state NMR with in situ infrared thermography, we show that the reaction proceeds through a reentrant order–disorder–order transformation. Layered Li-Mn-O intermediates disorder above 945mathematical equation to form the DRX phase, while continued heating drives reordering back to layered structures. Infrared profiles reveal a distinct feature marking completion of the disordering transition, enabling precise reaction termination to maximize DRX phase purity. We further examine the impact of phase purity on the “mathematical equation-phase” transition during electrochemical cycling and find that residual layered phases minimally affect performance. These findings indicate that mathematical equation is only stable near 945mathematical equation, yet its electrochemical performance tolerates synthesis-induced impurities.
|
Aug 2026
|
|
B18-Core EXAFS
|
Open Access
Abstract: A room temperature, continuous coprecipitation process with in-line dynamic mixing (ACTIM) was used to synthesize a precursor (up to 0.42 kg h−1) to the high-voltage cathode LiNi0.5Mn1.5O4 (LNMO), consuming ~39% less energy at the coprecipitation step than a more conventional batch synthesis route. The coprecipitate was lithiated in air via a two-step heat treatment (500 °C/5 h and then 850 °C/12 h), followed by a third treatment at 650, 700 or 750 °C to tune cation disorder. X-ray Photoelectron Spectroscopy (XPS) gave surface Mn3+ fractions of ca. 38, 46 and 53% for the 650, 700 and 750 °C samples, respectively, with (Mn K-edge) X-ray Absorption Spectroscopy (XAS) indicating the same trend in the bulk. The 750 °C sample under electrochemical testing, delivered a specific capacity of 124, 116 and 81 mAh g−1 at 0.1, 1 and 5 C, respectively. Furthermore, adding 2.5 wt % multi-walled carbon nanotubes (MWCNTs) to the electrode raised the rate capability to 98 mAh g−1 at 5 C and 91 mAh g−1 at 10 C, with 98.4% capacity retention after 100 cycles at a 1 C current rate. The primary contribution of this work lies in demonstrating that a scalable, ambient temperature, energy-efficient continuous-flow coprecipitation process can produce LNMO cathodes with tunable disorder-related characteristics.
|
Aug 2026
|
|
I11-High Resolution Powder Diffraction
|
Matthew
Wright
,
Stephen
Browne
,
Enrique
Moya
,
Amelia R.
Reach
,
Aina
Sebastian
,
Aliya
Abulajiang
,
Roland
Yin
,
Julissa
Cesareo
,
Jacey
Li
,
Alejandro
Tarin
,
Sarah H.
Tolbert
,
Brent C.
Melot
,
Anton
Van Der Ven
,
Ram
Seshadri
Diamond Proposal Number(s):
[36397, 41364]
Abstract: Layered Na–Mn–Fe–O oxides are among the leading cathode candidates for Na-ion batteries owing to their low cost, earth-abundant constituents, and competitive electrochemical performance. Their rich structural chemistry, spanning O-type (octahedral Na) and P-type (prismatic Na) polymorphs with distinct stacking sequences, offers multiple avenues for property optimization. However, controllable access to specific polymorphs, particularly nonequilibrium ones, remains a synthetic challenge. Here we show that susceptor-assisted microwave heating can produce the P2, O3, and P3 phases of layered Na–Mn–Fe–O cathodes in minutes, with phase selectivity set by the nominal Na/M ratio of the precursor alone. The rapid reaction times suppress Na volatilization, preserving the target stoichiometry without the excess sacrificial Na precursors typically required by conventional solid-state routes. The high mobility of Na+ combined with the large size difference between Na and Mn/Fe, yields well-ordered frameworks with no evidence for antisite disorder between Na+ and the transition metals. Accessing all three structures from one rapid route enables a controlled comparison of how stacking sequence governs electrochemistry. On cycling, we observe Fe3+/Fe4+ redox and behavior consistent with Fe3+ migration into the Na layer at high voltage in all three polymorphs, with P2 showing the most stable high-voltage cycling. Operando diffraction shows that all three converge toward disordered O-type stacking on deep desodiation, and voltage-resolved distribution-of-relaxation-times analysis shows that Na+ diffusion kinetics are governed by stacking transitions and Na–vacancy ordering, with pronounced kinetic barriers at glide-type structural transitions. These results establish microwave synthesis as a versatile route to both equilibrium and nonequilibrium layered Na cathodes and clarify how stacking sequence and local disorder jointly control redox behavior and ion transport.
|
Aug 2026
|
|
I11-High Resolution Powder Diffraction
|
Matthias
Hartmann
,
Phuong Nam
Le Pham
,
Jacob C.
Hickey
,
Alexandra
Morscher
,
Marvin A.
Kraft
,
Max
Wacha
,
Eamonn T.
Connolly
,
Lucy K.
Saunders
,
Jürgen
Janek
,
Wolfgang G.
Zeier
,
Xabier
Martinez De Irujo Labalde
Diamond Proposal Number(s):
[35814, 38368]
Abstract: This work revisits the K+-ion-conducting K3–xSb1–xWxS4 (0 ≤ x ≤ 0.10) system and finds a more complex structural scenario than previously reported. K3SbS4 does not only crystallize in the reported Cmc21 space group but also in a structure best described in the R3c space group. Both polymorphs are present at room temperature, whereas variable-temperature synchrotron X-ray diffraction shows that only the R3c phase persists at elevated temperatures. Similarly, the substitution of Sb(+V) with W(+VI) stabilizes the high-temperature R3c polymorph. K3SbS4 further shows similar diffusion pathways for both polymorphs. It matches the measured transport properties dominated by W(+VI) substitution, increasing ionic conductivity up to 0.64 mS·cm–1 at 298 K for nominal K2.92Sb0.92W0.08S4 with an activation energy of 0.29 eV. This work emphasizes the need for a complementary understanding of atomic arrangement and microstructure in potassium-ion conductors.
|
Aug 2026
|
|
I07-Surface & interface diffraction
|
Diamond Proposal Number(s):
[36456]
Open Access
Abstract: Vacuum-deposited organic solar cells (OSCs) have lagged behind their solution-processed counterparts in achieving high power conversion efficiency (PCE), in particular as result of higher voltage losses. In this study, we demonstrate a bulk heterojunction OSC using SubNc as donor and DCV3T as non-fullerene acceptor, achieving a PCE of 2.6% and a remarkably low total voltage loss of 0.64 V, lower than the typical values exceeding 0.7 V observed in vacuum thermally evaporated fullerene-based systems. The device also exhibits non-radiative voltage losses comparable to leading non-fullerene-acceptor (NFA) based OSCs. Transient absorption spectroscopy confirms efficient Förster resonance energy transfer from DCV3T to SubNc, followed by electron transfer for exciton separation. Morphological Grazing Incidence Wide-Angle X-ray Scattering features suggest both blends have a preferential edge-on orientation of DCV3T molecules, and the blends with higher DCV3T content could suffer from suppressed out-of-plane lamellar crystallinity with possible connection with greater non-radiative losses. Our findings demonstrate the potential of designing low-voltage-loss evaporated OSCs by building on strategies from solution-processed NFA systems, while highlighting the continued need for new evaporable acceptors with optimised optoelectronic and morphological properties.
|
Jul 2026
|
|
B18-Core EXAFS
|
Zixuan
Li
,
Rui
Qi
,
Yee Chit
Wong
,
Longlong
Wang
,
Jun
Chen
,
Yi
Yuan
,
Reinhard J.
Maurer
,
Robert A.
House
,
Nicholas D. M.
Hine
,
Peter G.
Bruce
,
Alex W.
Robertson
Diamond Proposal Number(s):
[38258]
Open Access
Abstract: Multivalent batteries, particularly zinc-ion batteries (ZIBs), are promising candidates for high-energy–density energy storage. However, their development is hindered by a scarcity of suitable cathode materials capable of the reversible (de)intercalation of Zn2+. To address this challenge, we propose cation-disordered rocksalt (DRX) cathodes, which have demonstrated excellent performance in Li-ion batteries, as a versatile host framework for nonaqueous ZIBs. Specifically, a vacancy-containing Mn0.4Ti0.4O2 DRX cathode demonstrates a reversible capacity of 170 mAh g−1 in nonaqueous ZIBs. Our investigation reveals that the Zn2+ ionic diffusion mechanism within the DRX framework is intrinsically sluggish compared to monovalent ions like Li+ due to strong electrostatic repulsion. Therefore, to successfully unlock Zn2+ migration, we show that it is necessary to introduce cation vacancies into the host, which significantly reduces the ion migration barrier. Additionally, we suggest that anion engineering may further enhance diffusion kinetics. This work expands the cathode material landscape for ZIBs and provides general insights into the design of disordered hosts for multivalent ion storage.
|
Jul 2026
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[41187]
Abstract: The sulfur redox mechanism in solid-state lithium–sulfur (Li–S) batteries remains unclear, as it has been reported to vary under different operating conditions due to sluggish reaction kinetics. Herein, we investigate sulfur reactions in solid-state batteries using solid electrolytes with high ionic conductivities to mitigate kinetic limitations. A solid-state Li–S cell employing Li5.5PS4.5Cl1.5 exhibits an asymmetric voltage profile at 25 °C, with two voltage plateaus during discharge and poorly separated oxidation reactions during charge. Ex situ X-ray absorption spectroscopy (XAS) elucidates that these poorly separated oxidation reactions consist of overlapping conversion reactions, in contrast to the clearly distinguishable two-step conversion from S8 to Li2S via Li2Sx during discharge. In addition, operando impedance evolution, analyzed using a combined distribution of relaxation times (DRT) and distribution of phasances (DOP) model, reveals distinct relaxation processes during discharge and charge that arise from differences in the transport properties of the reaction products. This work demonstrates an intrinsic asymmetric sulfur redox mechanism in solid-state batteries that is difficult to resolve by conventional electrochemical measurements alone but can be clarified by combining XAS with impedance analysis using the DRT-DOP model.
|
Jul 2026
|
|
