B18-Core EXAFS
E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[42584]
Open Access
Abstract: Sluggish kinetics of redox reactions and slow ion transport restrict the performance of lithium-sulfur (Li─S) batteries. Here, we fabricate cathodes containing vertically aligned porous structures hosting atomically dispersed Fe─N4 single-atom catalyst (SAC) sites on graphitic carbon nitride (g-C3N4). Density functional theory (DFT) calculations suggest that the Fe─N4 sites strengthen Li2S adsorption, optimize electronic structure, and lower the reaction energy change associated with liquid-solid transition and Li2S oxidation. Experimental results demonstrate that the atomically dispersed Fe─N4 sites in the vertically aligned porous cathodes made by directional ice templating (DIT) accelerate Li+ ion transport and enable high sulfur loading while exposing abundant catalytic centers, resulting in strong polysulfide affinity, promoted nucleation and decomposition of Li2S bidirectional redox catalysis, and suppressed polysulfide shuttle effect. Benefiting from this structural-catalytic synergy, the cathode delivers a high capacity of 1299.2 mAh g−1 at 0.1 C, and the capacity is retained at 505.9 mAh g−1 after 1 000 cycles at 0.5 C, with a low capacity decay rate of ∼0.042% per cycle. This study highlights a scalable strategy to integrate SAC with vertically aligned porous electrode architecture that promotes fast kinetics of sulfur redox in both directions and mass transport for Li─S batteries.
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Sep 2026
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E02-JEM ARM 300CF
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Leyuan
Zhang
,
Dongfang
Cheng
,
Pu
Zhang
,
David G.
Hopkinson
,
Zhaozong
Wang
,
Ao
Zhang
,
Chen
Li
,
Ran
Wang
,
Rongli
Liu
,
Christopher S.
Allen
,
Johanna
Nelson Weker
,
Yu
Huang
,
Philippe
Sautet
,
Xiangfeng
Duan
Diamond Proposal Number(s):
[32750]
Open Access
Abstract: Lithium–sulfur batteries are fundamentally constrained by the sluggish 16-electron sulfur reduction reaction. Electrocatalytic sulfur reduction reaction is inherently complex, involving multiple lithium polysulfide intermediates (Li2Sn, n = 2–8), each with distinct adsorption and activation requirements, leading to unbalanced polysulfide conversion and severe shuttle effect. Although cascade catalysis has been proposed as a potential solution, the precise pathway and its mechanistic role in regulating polysulfide conversion remain elusive. Here we elucidate and experimentally validate the complete cascade pathway of sulfur reduction on Fe,N,S-codoped holey graphene as a model catalyst. Density functional theory reveals that Fe sites preferentially bind and activate long-chain polysulfides, while N,S-C sites accelerate the conversion of Li2S4 to Li2S2/Li2S. Such site-specific synergy balances sulfur reduction kinetics and suppresses polysulfide accumulation. Combined kinetic analysis and operando Raman spectroscopy directly reveal how synergistic cascade catalysis governs the reaction pathway, modulates key intermediates, and enables balanced polysulfide conversion. Together, these results establish cascade catalysis as a mechanism-driven design strategy for lithium–sulfur battery electrodes, where regulation of the reaction pathway suppresses polysulfide shuttling and enables enhanced cycling stability.
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Jul 2026
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E02-JEM ARM 300CF
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Luke T.
Norman
,
William J.
Cull
,
Craig T.
Stoppiello
,
Christopher S.
Allen
,
Johannes
Biskupek
,
Maxwell A.
Astle
,
Rhys W.
Lodge
,
Ute
Kaiser
,
Jesum
Alves Fernandes
,
Graham A.
Rance
,
Andrei N.
Khlobystov
Diamond Proposal Number(s):
[25251]
Open Access
Abstract: The formation of inorganic nanomaterials is highly sensitive to the local environment. When environmental conditions are carefully selected, they enable precise control over the composition, shape and dimensionality of inorganic nanostructures, which, in turn, influences their functional properties. In this study, we explore the impact of single-walled carbon nanotubes (SWNTs) on the sequential transformation of triosmium dodecacarbonyl (Os3(CO)12) into osmium iodide (OsI) and subsequently osmium disulphide (OsS2). Initially, the nanotubes form a van der Waals complex with Os3(CO)12, allowing the molecules to retain their structure and properties, unaffected by the presence of the SWNT, as determined by direct imaging using high-resolution transmission electron microscopy (HRTEM) and evaluation of metal atom valence states by X-ray photoelectron spectroscopy (XPS). When iodine is introduced, it triggers a chemical transformation of the metal carbonyl to iodide (OsI) in a NaCl-like cubic phase. The nanotubes play a crucial role by providing electrons from their valence band, as evidenced by resonance Raman spectroscopy. The structure of OsI depends significantly on its position relative to the nanotube: disk-like particles measuring 4–6 nm form on the exterior, while sub-nanometer-wide wires form within the internal cavity, the latter exhibiting tumbling motion within the SWNT, resulting in different projections in HRTEM images. The hybrid OsI-SWNT material shows ionic character and readily reacts with hydrogen sulphide, converting into OsS2. During this reaction, SWNTs regain their electrons and become charge neutral. OsS2 nanoparticles consist of two distinct phases: a standard pyrite-like cubic phase forms the core of the particles, while a hexagonal phase creates the shell (c-OS2@h-OsS2). Inside SWNTs, however, OsS2 forms a nanowire that is one unit cell wide and twists along the length of the nanotube. The nanotube serves as a protective shell for the undercoordinated osmium atoms located at the edges of the nanowire. We showed that in inorganic transformations, the SWNT acts both as a template for the growth of osmium-based nanoparticles and an analytical platform for the detailed characterisation and comparison of nanostructures formed with and without spatial constraints, facilitating the discovery of new crystal phases such as OsI and hybrid nanostructures of c-OS2@h-OsS2 reported in this study.
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Apr 2026
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E02-JEM ARM 300CF
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Sam
Sullivan-Allsop
,
Nick
Clark
,
Wendong
Wang
,
Rongsheng
Cai
,
William
Thornley
,
David G.
Hopkinson
,
James G.
Mchugh
,
Ben
Davies
,
Samuel
Pattisson
,
Nicholas F.
Dummer
,
Rui
Zhang
,
Matthew
Lindley
,
Gareth
Tainton
,
Jack
Harrison
,
Hugo
De Latour
,
Joseph
Parker
,
Joshua
Swindell
,
Eli G.
Castanon
,
Amy
Carl
,
David J.
Lewis
,
Natalia
Martsinovich
,
Christopher S.
Allen
,
Mohsen
Danaie
,
Andrew J.
Logsdail
,
Vladimir
Fal’ko
,
Graham J.
Hutchings
,
Alex
Summerfield
,
Roman
Gorbachev
,
Sarah J.
Haigh
Diamond Proposal Number(s):
[33252, 35552]
Abstract: The structure and dynamics of adsorbed atoms (adatoms) at solid-liquid interfaces determine the performance of advanced catalysts, electrochemical devices, molecular separation technologies, and metal extraction from waste streams. However, in situ investigations of atomically dispersed metals in various chemical environments have been prevented by insufficient imaging resolution and solvent incompatibility. In this study, we combined a specimen design that provides atomic resolution in liquid-phase electron microscopy with deep learning–enabled analysis to explore the interactions between gold adatoms, graphite support, and the solvent collectively. We tracked the locations of >106 graphite-supported gold adatoms, dimers, and larger clusters in five solvents. Although their initial atomic dispersion was determined by the solvent polarity, fast drying kinetics at low temperature was required for optimizing catalytic performance.
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Apr 2026
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[39072]
Open Access
Abstract: Potassium-ion batteries (KIBs) are a promising beyond–lithium-ion chemistry, offering advantages similar to sodium-ion systems in terms of earth-abundant materials and safety, with the additional benefit of reversible graphite intercalation and potential for improved low-temperature performance. These features make KIBs attractive for low-cost electric vehicles and stationary battery energy storage systems. However, they currently fall short of the cycle life required by these applications. A major source of capacity fade is instability of the solid electrolyte interphase (SEI), which is influenced by electrolyte chemistry, temperature, and the electrochemical history of the cell. Many studies use potassium metal as a proxy to investigate SEI behaviour on graphite. On potassium metal, the SEI can form chemically via direct reaction with the electrolyte or electrochemically during potassium plating. In contrast, during charging of a graphite electrode, SEI formation occurs exclusively through electrochemical reduction. It therefore remains unclear to what extent the SEI formed on potassium metal is representative of that formed on graphite. Here, we employ X-ray photoelectron spectroscopy (XPS) to probe differences between chemical and electrochemical SEI formation on potassium metal, graphite, and inert electrodes in two contrasting potassium bis(fluorosulfonyl)imide (KFSI)-based electrolytes: 1 m KFSI in tetraethylene glycol dimethyl ether (G4) and 1 m KFSI in 1,3-dioxane (13-DX). Four-dimensional scanning transmission electron microscopy (4D-STEM) phase mapping provides complementary structural insight. We establish relationships between SEI chemistry, electrolyte composition, electrode material, formation pathway, and applied potential, offering guidance for rational electrolyte design.
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Apr 2026
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[37041, 56733]
Open Access
Abstract: 2D Prussian blue and its analogues hold great promise for applications in catalysis, energy conversion, sensing, and memory devices, thanks to their open frameworks, surface activity, and directional ion transport. However, synthesizing high-quality and large-area 2D films remains a major challenge. Here, we present a robust and scalable liquid-liquid interfacial synthesis that enables the formation of continuous, 2D flakes of Prussian blue (Fe3+[Fe2+(CN)6]0.75) with tunable thicknesses from ∼2 nm to several hundred nanometers. The controlled reduction of [Fe3+(CN)6]3− to [Fe2+(CN)6]4− enables slow, directed growth of 2D-FeFe layers. Unlike films formed from nanoparticles, this method yields high-quality flakes suitable for integration into devices. As a demonstration, we incorporated these films into Ag filament-based electrochemical metallization memristors. The 2D-FeFe devices ≥50 nm thick exhibited reliable bipolar electrical switching, with high Roff/on ratios (∼106), >6 h retention, and stability over 150 cycles. Strikingly, switching was observed across 1.5 µm lateral gaps, far exceeding conventional silver filament formation distances, highlighting the superior ion transport and structural integrity of these 2D frameworks. This scalable approach to 2D Prussian blue, which has the potential to be extended to other related coordination polymers, offers exciting opportunities beyond memristors, enabling integration into technologies where thin-film compatibility, directional ion transport, and high surface activity are critical, such as catalysis, energy storage, and neuromorphic computing.
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Jan 2026
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E02-JEM ARM 300CF
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Evan David Innes
Tillotson
,
William
Thornley
,
William
Talbott
,
Alexander S.
Eggeman
,
Daria
Kriuchkova
,
Sam
Sullivan-Allsop
,
Matthew
Smith
,
Xuzhao
Liu
,
Ashley
Slattery
,
Pei Lay
Yap
,
Dusan
Losic
,
Zhun
Xu
,
Huan
Wang
,
Jim
Ciston
,
Alexander
Rakowski
,
Stephanie M.
Ribet
,
Benjamin H
Savitzky
,
Manfred Erwin
Schuster
,
Christopher S.
Allen
,
Danielle
Douglas-Henry
,
Valeria
Nicolosi
,
Andrew
Herzing
,
Jacques
O'Connell
,
Ezra J.
Olivier
,
Jan
Neethling
,
Yichao
Zou
,
Ercin Cagan
Duran
,
Rongsheng
Cai
,
Duc-The
Ngo
,
Roman
Gorbachev
,
Jonas
Haas
,
Michael
Schlegel
,
Jannik C.
Meyer
,
Alba
Centeno
,
Amaia
Pesquera
,
Amaia
Zurutuza
,
Sungsu
Kang
,
Jungwon
Park
,
Ivan
Erofeev
,
Utkur
Mirsaidov
,
Colin
Ophus
,
Christian
Rentenberger
,
Thomas
Waitz
,
Jani
Kotakoski
,
Abhijit
Roy
,
Raul
Arenal
,
Andrew
Pollard
,
Sarah
Haigh
Diamond Proposal Number(s):
[29951]
Open Access
Abstract: Standardisation of data collection and analysis is essential to enable commercialisation of 2D materials in a wide range of technologies. Selected area electron diffraction (SAED) in the transmission electron microscope (TEM) is one of the key methods for distinguishing monolayer from bilayer and few-layer graphene by comparing the 1st and 2nd order diffraction spot intensities. Yet there are many factors that can affect the reliability of data collection and interpretation, causing the measurement of monolayer samples to deviate from the literature boundary condition of I{-2110}/I{1-100}<1 for monolayer graphene. Here we present the results of a large interlaboratory SAED comparison study, where 15 international laboratories measured and analysed nominally identical samples of chemical vapour deposited (CVD) graphene. Large variations were observed in the measured ratios of diffraction spot intensities, with the largest variance associated with poor quality SAED data resulting from poor specimen handling and storage. To inform the reliable determination of monolayer thickness from SAED patterns we provide a description of best practice for specimen handling, TEM operation, data collection and analysis. This work was undertaken within VAMAS Technical Working Area (TWA) 41: Graphene and related 2D materials - Project 9, the results of which have been directly incorporated into ISO/TS 21356-2 for the characterisation of graphene sheets. We find that when this methodology is followed, monolayer graphene can be distinguished from bilayer or thicker material with high confidence where analysis of a single SAED pattern gives I{-2110}/I{1-100}<1.2, even in the absence of precise specimen tilting.
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Dec 2025
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[33430]
Open Access
Abstract: The electrochemical reduction of N2 in aqueous media and ambient conditions would present a great advancement in the defossilization of the fertilizer and energy sector, if the obstacles to this technology were not as significant as they are at present. Some recent reports have raised doubts about whether the electrochemical nitrogen reduction reaction (eNRR) is even possible in aqueous media. Herein, a type of metal-organic framework (MOF)-derived Fe and Zn single atom catalyst for the eNRR is revisited, which has been reported more than once in recent literature to be active for eNRR in aqueous media. Electrochemical measurements reported here show the inactivity of the investigated iron-based catalysts for the eNRR in neutral aqueous media when contaminations are excluded. In stark contrast, the reduction of NOx contamination to ammonia is shown to be a possible reason for false positive results. The reduction of nitrate to ammonia (NO3-RR) is itself an emerging field of research that investigates the conversion of nitrate from wastewater to ammonia. For the NO3-RR, the MOF-derived catalysts show good activity and selectivity, which depends on the iron site density in the catalyst. An ammonia yield of 19.1 mg h−1 mgcat−1 at −1.0 V versus RHE and a maximum faradaic efficiency (FE) of 100% at −0.9 V versus RHE is achieved.
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Dec 2025
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E01-JEM ARM 200CF
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Diamond Proposal Number(s):
[33481]
Open Access
Abstract: A novel heterostructured hexagonal-boron nitride (h-BN) flake-coating on multi-wall carbon nanotubes (MWCNT/BN) is reported and synthesized by chemical vapor deposition (CVD). Comprehensive characterization using X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM), combined with electron energy loss spectroscopy (EELS), revealed the atomic structure and growth mechanism, which is further validated by molecular dynamics simulations. The resulting MWCNT/BN structure comprises three distinct layers: an inner carbon nanotube (CNT) core, coaxial BN nanotubes (BNNTs) surrounding the CNT core, and outer BN flakes extending from the BNNTs. We propose that BN layers first form coaxial BNNTs on the CNT surface; as deposition proceeds, BN accumulation generate in-plane and out-of-plane compressive stresses in the h-BN layers. When these stresses exceed a critical threshold, local buckling or cracking occurs, BN flakes emerge and grow further. This work elucidates, for the first time, the formation mechanism of BN nanoflakes on MWCNTs and confirms that the structure is a van der Waals heterostructure. The approach also offers a new route for synthesizing coaxial MWCNT@BN with only a few h-BN layers. Notably, the BN flake coatings provide efficient phonon transport pathways and a large surface area, making this heterostructure highly promising for applications in thermal dissipation.
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Dec 2025
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[16967, 37411]
Open Access
Abstract: Atomic-scale wetting governs material formation at the nanoscale but remains poorly understood under confinement, where classical capillarity models fail. The growth of metallic nanowires within multi-wall carbon nanotubes (MWCNTs) exemplifies this challenge, requiring precise control over wetting, nucleation, and vapour-phase condensation. Here we show that nanowire formation proceeds through a two-stage mechanism: curvature-driven nucleation at open tube ends followed by capillary-driven elongation sustained by continuous vapour condensation. Using in situ atomic-resolution transmission electron microscopy (ARTEM) coupled with a deep learning convolutional neural network (CNN) capable of classifying liquid, solid and intermediate SnxO phase transitions, we directly capture the cascade of thermally induced nanowire growth within CNTs. Growth requires a wetting interface (contact angle, θ <90°) between liquid SnxO and the nanotube wall—conditions not described by Kelvin or Lucas–Washburn models. These results establish a predictive framework for vapour-phase nanowire encapsulation, linking nanoscale wetting dynamics to the fabrication of advanced nanomaterials.
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Nov 2025
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