B18-Core EXAFS
E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Conventional catalytic CO2 reduction into value-added products often encounters challenges such as high energy barriers and complex operational setups. Here, we introduce a sonocatalysis approach to CO2 reduction in water under ambient conditions. In an acoustic cavitation-induced high-energy local environment, the Cu nanoparticles incorporated on the ZnAl-layered double oxide create a favorable energy barrier for CO2 reduction in water, a CO production rate of 23.8 μmolCO g−1 h−1 with over 85% selectivity was achieved by ultrasonic irradiation of a CO2-saturated aqueous solution at room temperature. Furthermore, more acoustic cavitation was produced with 5% CO2 in argon dissolved in water, resulting in a higher CO productivity of 252.7 μmolCO g−1 h−1, 11 times larger than pure CO2. Hydrogen production also increased with acoustic cavitation, creating a syngas mixture with a CO to H2 ratio of 1.2 to 2.2. This approach produces a high sonochemical efficiency of 211.1 μmol kJ−1 g−1 L−1 for the ultrasound-driven fuel production from CO2 and water. These results highlight the use of cavitation to provide an alternative approach to CO2 conversion.
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May 2025
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I13-2-Diamond Manchester Imaging
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Mengzheng
Ouyang
,
Zhenyu
Guo
,
Luis E.
Salinas-Farran
,
Siyu
Zhao
,
Mengnan
Wang
,
Feiran
Li
,
Yan
Zhao
,
Kaitian
Zheng
,
Hao
Zhang
,
Guangdong
Li
,
Xinhua
Liu
,
Shichun
Yang
,
Fei
Xie
,
Paul
Shearing
,
Maria-Magdalena
Titirici
,
Nigel
Brandon
Diamond Proposal Number(s):
[34782]
Open Access
Abstract: Sodium-ion batteries (SIBs) are cost-effective alternatives to lithium-ion batteries (LIBs), but their low energy density remains a challenge. Current electrode designs fail to simultaneously achieve high areal loading, high active content, and superior performance. In response, this work introduces an ideal electrode structure, featuring a continuous conductive network with active particles securely trapped in the absence of binder, fabricated using a universal technique that combines electrospinning and electrospraying (co-ESP). We found that the particle size must be larger than the network's pores for optimised performance, an aspect overlooked in previous research. The free-standing co-ESP Na2V3(PO4)3 (NVP) cathodes demonstrated state-of-the-art 296 mg cm-2 areal loading with 97.5 wt.% active content, as well as remarkable rate-performance and cycling stability. Co-ESP full cells showed uncompromised energy and power densities (231.6 Wh kg-1/7152.6 W kg-1), leading among reported SIBs with industry-relevant areal loadings. The structural merit is analysed using multi-scale X-ray computed tomography, providing valuable design insights. Finally, the superior performance is validated in the pouch cells, highlighting the electrode’s scalability and potential for commercial application.
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May 2025
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I11-High Resolution Powder Diffraction
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Zhengyan
Lun
,
Alice J.
Merryweather
,
Amoghavarsha
Mahadevegowda
,
Shrinidhi S.
Pandurangi
,
Chao
Xu
,
Simon
Fairclough
,
Vikram
Deshpande
,
Norman A.
Fleck
,
Caterina
Ducati
,
Christoph
Schnedermann
,
Akshay
Rao
,
Clare P.
Grey
Open Access
Abstract: Extensive worldwide efforts have been made to understand the degradation behavior of layered Ni-rich LiNixMnyCo(1−x−y)O2 (NMC) cathodes. The majority of studies carried out to date have focused on thermodynamic perspectives and are conducted ex situ; operando investigations on aged materials, especially those that can resolve dynamic information in a single-particle level remain sparse, preventing the development of long-term stable NMCs. Here, we directly visualize the real-time Li-ion transport kinetics of aged Ni-rich single-crystal NMC under operando conditions and at single-particle level using a recently developed optical microscopy technique. For both fresh and aged particles, we identify Li-ion concentration gradients developing during the early stages of delithiation – resulting in a Li-rich core and Li-poor surface – as observed previously and attributed to low Li-ion diffusivity at high Li-occupancies. Critically, in contrast to fresh particles, the Li-ion gradients in aged particles become markedly asymmetric, with the Li-rich core shifted away from the center of mass of the particle. Using ex situ transmission electron microscopy, we show that cell aging produces an uneven build-up of a surface rocksalt layer. Supported by finite-element modelling, we attribute the asymmetric delithiation behavior of the aged particles to this uneven rocksalt layer, which impedes the Li-ion flux heterogeneously at the particle surface. Our results demonstrate a new mechanism that contributes to the capacity and rate degradation of Ni-rich cathodes, highlighting the importance of controlling the build-up of detrimental interfacial layers in cathodes and providing a rational for improving the long-term stability and rate capabilities of Ni-rich NMC cathodes.
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Mar 2025
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I09-Surface and Interface Structural Analysis
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Diamond Proposal Number(s):
[30759]
Open Access
Abstract: Metal-oxide coatings are a favoured strategy for mitigating surface degradation problems in state-of-the-art lithium-ion battery Ni-rich layered positive electrode materials. Despite their extensive use, a full, fundamental understanding of the role of coatings in reducing degradation and extending cycling lifetimes is currently lacking. In this work, the interactions between an atomic layer deposited (ALD) alumina coating on polycrystalline LiNi0.8Mn0.1Co0.1O2 (NMC811) and a carbonate-based battery electrolyte are studied. Solid-state nuclear magnetic resonance (ssNMR) heteronuclear experiments show that the Al2O3 coating transforms by reacting with electrolyte species present before and during electrochemical cycling, scavenging protic and acidic species. Density-functional theory calculations highlight the additional chemical effect of the coating in locally stabilising the structure of the NMC811, limiting oxidation of the oxygen atoms coordinated to both Al and Ni, thereby limiting the surface reconstruction process and improving the electrochemical performance. Improved NMC811 surface stability is confirmed by monitoring gaseous degradation species by online electrochemical mass-spectrometry and via X-ray spectroscopic analysis of the electrochemically aged samples to examine changes in Ni and O oxidation state and local structure. The combination of this experimental and theoretical analysis suggests that Al2O3 coatings have a dual role: as a protective barrier against attack from chemical species in the electrolyte, and as an artificial passivating layer hindering oxygen loss and surface phase transformations. This holistic approach, which provides a fundamental understanding of how the surface stability is improved by the coating, will aid the design of the state-of-the-art and future positive electrode materials.
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Jan 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[36104]
Abstract: The sulfion oxidation reaction (SOR) assisted seawater electrolysis has been proposed to be a potentially cost-effective approach to hydrogen production because SOR happens at an anodic potential significantly lower than that of the energy-demanding oxygen evolution reaction (OER). However, the key to unleash full potential of SOR for practical seawater electrolysis is to develop highly efficient and stable electrocatalysts able to sustain in harsh seawater environment at high current densities. Herein, we report the fabrication of nickel foam supported nickel telluride nanorod arrays covered conformally with an electrodeposited amorphous nickel molybdenum layer (NiTe@NiMo/NF), which exhibit outstanding SOR performance, capable of delivering 500 mA cm−2 at only 0.55 V vs. reversible hydrogen electrode (RHE) and operating at 500 mA cm−2 for 100 hours without degradation, in both simulated and natural seawater. Our comprehensive experimental and theoretical studies reveal that the NiTe@NiMo/NF electrode undergoes a dynamic reconstruction process, and the in-situ generated [MoO4]2− moieties can modulate and stabilize the catalytically active NiTe/NiOOH, improving the SOR activity and stability. Consequently, the asymmetric membrane electrode assembly comprising NiTe@NiMo/NF as the anode can deliver a current density as large as 5.0 A cm−2 at 1.33 V in alkaline natural seawater at 70 °C and operate at 1.0 A cm−2 below 1.0 V for 334 hours, holding great potential for energy-saving and cost-competitive hydrogen production from seawater.
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Dec 2024
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Gukhyun
Lim
,
Min Kyung
Cho
,
Jaewon
Choi
,
Ke-Jin
Zhou
,
Dongki
Shin
,
Seungyun
Jeon
,
Minhyung
Kwon
,
A-Re
Jeon
,
Jinkwan
Choi
,
Seok Su
Sohn
,
Minah
Lee
,
Jihyun
Hong
Abstract: Exploiting oxygen anion redox in Li-/Mn-rich layered oxides (LMR-NMCs) offers the highest capacity among cathode materials for Li-ion batteries (LIBs). However, its long-term utilization is challenging due to continuous voltage and capacity decay caused by irreversible phase transitions involving cation disordering and oxygen release. While extensive studies have revealed the thermodynamic origin of cation disordering, the mechanisms of oxygen loss and consequent lattice densification remain elusive. Moreover, mixed spinel-rocksalt nanodomains formed after cycling complicate the degradation mechanism. Herein, we reveal a strong correlation between phase transition pathways and oxygen stability at the particle surface in LMR-NMCs through a comparative study using electrolyte modification. By tailoring surface reconstruction pathways, we control the overall phase and electrochemistry evolution mechanisms. Removing polar ethylene carbonate from the electrolyte significantly suppresses irreversible oxygen loss at the cathode–electrolyte interface, preferentially promoting the in situ layered-to-spinel phase transition while avoiding typical rocksalt phase formation. The in situ formed spinel-stabilized surface enhances charge transfer kinetics through three-dimensional ion channels, maintaining reversible Ni, Mn, and O redox capability over 700 cycles, as revealed by electron microscopy, X-ray absorption spectroscopy, and resonant inelastic X-ray scattering. Deep delithiation and lithiation enabled by the surface spinel phase accelerate the bulk layered-to-spinel phase transition, inducing thermodynamic voltage fade without capacity loss. Conversely, conventional electrolytes induce layered-to-rocksalt surface reconstruction, impeding charge transfer reactions, which causes simultaneous capacity and (apparent) voltage fades. Our work decouples thermodynamic and kinetic aspects of voltage decay in LMR-NMCs, establishing the correlation between surface reconstruction, bulk phase transition, and the electrochemistry of high-capacity cathodes that exploit cation and anion redox couples. This study highlights the significance of electrochemical interface stabilization for advancing Mn-rich cathode chemistries in future LIBs.
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Nov 2024
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
I10-Beamline for Advanced Dichroism - scattering
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Lijin
An
,
Ruomu
Zhang
,
Prvanin N.
Didwal
,
Michael W.
Fraser
,
Leanne A. H.
Jones
,
Conor M. E.
Phelan
,
Namrata
Ramesh
,
Grant
Harris
,
Robert S.
Weatherup
,
Jack E. N.
Swallow
,
Peixi
Cong
,
Andrey
Poletayev
,
Erik
Bjorklund
,
Christophe J.
Sahle
,
Pilar
Ferrer
,
David C.
Grinter
,
Peter
Bencok
,
Shusaku
Hayama
,
Saiful
Islam
,
Robert
House
,
Peter D.
Nellist
,
Robert J.
Green
,
Rebecca J.
Nicholls
Diamond Proposal Number(s):
[33283, 33062, 32010]
Open Access
Abstract: Ni-rich layered oxide cathodes can deliver higher energy density batteries, but uncertainties remain over their charge compensation mechanisms and the degradation processes that limit cycle life. Trapped molecular O2 has been identified within LiNiO2 at high states of charge, as seen for Li-rich cathodes where excess capacity is associated with reversible O-redox. Here we show that bulk redox in LiNiO2 occurs by Ni-O rehybridization, lowering the electron density on O sites, but importantly without the involvement of molecular O2. Instead, trapped O2 is related to degradation at surfaces in contact with the electrolyte, and is accompanied by Ni reduction. O2 is removed on discharge, but excess Ni2+ persists forming a reduced surface layer, associated with impeded Li transport. This implicates the instability of delithiated LiNiO2 in contact with the electrolyte in surface degradation through O2 formation and Ni reduction, highlighting the importance of surface stabilisation strategies in suppressing LNO degradation.
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Sep 2024
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E02-JEM ARM 300CF
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Jihoo
Lim
,
Jaehui
Kim
,
Josh
Davies-Jones
,
Mohsen
Danaie
,
Eunyoung
Choi
,
Hongjae
Shim
,
Liang
Chen
,
Jincheol
Kim
,
Judy S.
Kim
,
Philip R.
Davies
,
Jan
Seidel
,
Martin
Green
,
Samuel D.
Stranks
,
Sang Il
Seok
,
Jae
Yun
Diamond Proposal Number(s):
[34931]
Abstract: Efforts to enhance the efficiency and stability of formamidinium lead triiodide (FAPbI3) perovskite solar cells (PSCs) have primarily focused on employing methylammonium chloride (MACl) as an effective additive. MACl significantly improves the crystallinity and lowers the δ-to-α phase transition temperature of FAPbI3, thereby contributing to the remarkable efficiency of these solar cells. However, upon evaporation with deprotonation of MACl during annealing, the highly reactive methylamine leads to the formation of N-methylformamidinium (MFA+) cations. Despite their potential for significant influence on the properties of FAPbI3 perovskites, the chemical and optoelectronic characteristics of MFA+ in FAPbI3 remain poorly understood. This study investigates the unexplored role of MFA+ in FAPbI3 perovskite with MACl incorporation through advanced nanoscale characterization techniques, including photo-induced force microscopy (PiFM), four-dimensional scanning transmission electron microscopy, and wavelength-dependent Kelvin probe force microscopy (KPFM). We reveal that MACl induces compositional heterogeneities, particularly formamidinium (FA+) and MFA+ cation inhomogeneities. Surprisingly, MACl selectively promotes the formation of MFAPbI3 at grain boundaries (GBs) and as clusters near GBs. Additionally, we confirm that MFAPbI3 is a wide bandgap, and charge carriers are effectively separated at GBs and clusters enriched with MFAPbI3. This is particularly interesting because MFAPbI3, despite its crystal structural similarity to yellow phase δ-FAPbI3, displays a high surface photovoltage, and does not deteriorate the solar cell performance. This study not only provides insights into the byproduct formation of MFA+ induced by local cation heterogeneity after employing MACl, but also guides a crucial perspective for optimizing formamidinium-based PSC design and performance.
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Aug 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
I21-Resonant Inelastic X-ray Scattering (RIXS)
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Mikkel
Juelsholt
,
Jun
Chen
,
Miguel A.
Pérez-Osorio
,
Gregory
Rees
,
Sofia
De Sousa Coutinho
,
Helen E.
Maynard-Casely
,
Jue
Liu
,
Michelle
Everett
,
Stefano
Agrestini
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Robert A.
House
,
Peter G.
Bruce
Diamond Proposal Number(s):
[27764, 29028]
Open Access
Abstract: LiNiO2 remains a critical archetypal material for high energy density Li-ion batteries, forming the basis of Ni-rich cathodes in use today. Nevertheless, there are still uncertainties surrounding the charging mechanism at high states of charge and the potential role of oxygen redox. We show that oxidation of O2− across the 4.2 V vs. Li+/Li plateau forms O2 trapped in the particles and is accompanied by the formation of 8% Ni vacancies on the transition metal sites of previously fully dense transition metal layers. Such Ni vacancy formation on charging activates O-redox by generating non-bonding O 2p orbitals and is necessary to form vacancy clusters to accommodate O2 in the particles. Ni accumulates at and near the surface of the particles on charging, forming a Ni-rich shell approximately 5 nm thick; enhanced by loss of O2 from the surface, the resulting shell composition is Ni2.3+1.75O2. The overall Ni oxidation state of the particles measured by XAS in fluorescence yield mode after charging across the plateau to 4.3 V vs. Li+/Li is approximately +3.8; however, taking account of the shell thickness and the shell Ni oxidation state of +2.3, this indicates a Ni oxidation state in the core closer to +4 for compositions beyond the plateau.
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Mar 2024
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
E01-JEM ARM 200CF
E02-JEM ARM 300CF
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Fangjia
Zhao
,
Jianwei
Li
,
Arunabhiram
Chutia
,
Longxiang
Liu
,
Liqun
Kang
,
Feili
Lai
,
Haobo
Dong
,
Xuan
Gao
,
Yeshu
Tan
,
Tianxi
Liu
,
Ivan P.
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[32905, 29340, 32058]
Open Access
Abstract: The design and synthesis of manganese oxide-based materials with high-rate performance and long cycle life is a major challenge for aqueous zinc-ion batteries (AZIBs). This research reports the presence of a synergistic collaboration between vacancies, lattice water and nickel ions on enhancing the hydrated protons hopping via the Grotthuss mechanism for high-performance zinc ion batteries. The Grotthuss mechanism allows for the efficient transfer of a proton charge without the actual movement of the molecule over long distances, resulting in high ionic conductivity. NiMn3O7·3H2O achieves a capacity of 318 mA h g−1 under 200 mA g−1 and 121 mA h g−1 under 5 A g−1 with a retention of 91% after 4000 cycles. The relationship between the remarkable performance and Grotthuss topochemistry is investigated using techniques including synchrotron X-ray absorption spectroscopy and density functional theory. Protons prefer to bond with O2− ions on the Mn–O layer, and proton transfer is favoured in the presence of vacancies. The continuous hopping of protons within the host material induces periodic, temporary local structural changes in the lattice. This dynamic behaviour alters the energy barriers for ions intercalation and deintercalation. Nickel ions facilitate the ongoing mobility of hydrated protons via Grotthuss hopping by preserving the system's electrical neutrality, which counterbalances the dynamic changes caused by proton migration. This study provides insight into the Grotthuss conduction mechanism for the development of high-performance cathode materials in AZIBs.
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Jan 2024
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