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Ralf F.
Ziesche
,
James B.
Robinson
,
Henning
Markötter
,
Robert
Bradbury
,
Alessandro
Tengattini
,
Nicolas
Lenoir
,
Lukas
Helfen
,
Winfred
Kockelmann
,
Nikolay
Kardjilov
,
Ingo
Manke
,
Dan J. L.
Brett
,
Paul
Shearing
Open Access
Abstract: The ability to track electrode degradation, both spatially and temporally, is fundamental to understand performance loss during operation of lithium batteries. X-ray computed tomography can be used to follow structural and morphological changes in electrodes; however, the direct detection of electrochemical processes related to metallic lithium is difficult due to the low sensitivity to the element. In this work, 4-dimensional neutron computed tomography, which shows high contrast for lithium, is used to directly quantify the lithium diffusion process in spirally wound Li/SOCl2 primary cells. The neutron dataset enables the quantification of the lithium transport from the anode and the accumulation inside the SOCl2 cathode to be locally resolved. Complementarity between the collected neutron and X-ray computed tomographies is shown and by applying both methods in concert we have observed lithium diffusion blocking by the LiCl protection layer and identified all cell components which are difficult to distinguish using one of the methods alone.
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Nov 2020
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Open Access
Abstract: The understanding of dynamic processes in Li-metal batteries is an important consideration to enable the full capacity of cells to be utilised. These processes, however, are generally not directly observable using X-ray techniques due to the low attenuation of Li; and are challenging to visualise using neutron imaging due to the low temporal resolution of the technique. In this work, complementary X-ray and neutron imaging are combined to track the dynamics of Li within a primary Li/SOCl2 cell. The temporal challenges posed by neutron imaging are overcome using the golden ratio imaging method which enables the identification of Li diffusion in operando. This combination of techniques has enabled an improved understanding of the processes which limit rate performance in Li/SOCl2 cells and may be applied beyond this chemistry to other Li-metal cells.
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Oct 2020
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E01-JEM ARM 200CF
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Ruoyu
Xu
,
Jingwei
Xiang
,
Junrun
Feng
,
Xuekun
Lu
,
Zhangxiang
Hao
,
Liqun
Kang
,
Ming
Li
,
Yunsong
Wu
,
Chun
Tan
,
Yiyun
Liu
,
Guanjie
He
,
Dan J. L.
Brett
,
Paul R.
Shearing
,
Lixia
Yuan
,
Yunhui
Huang
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[17559, 19318, 19246, 20643]
Abstract: The lithium-sulfur (Li-S) batteries have high theoretical energy density, exceeding that of the lithium-ion batteries. However, their practical applications are hindered by the capacity decay due to lithium polysulfide shuttle effect and sulfur volume expansion. Here, we design a S@hollow carbon with porous shell/MnOx (S@HCS/MnOx) cathode to accommodate and immobilize sulfur and polysulfides, and develop a non-destructive technique X-ray computed tomography (X-ray CT) to in situ visualize the volume expansion of Li-S cathode. The designed cathode achieves a specific capacity of ~1100 mAh g-1 at 0.2 C with a fade rate of 0.18% per cycle over 300 cycles. The X-ray CT shows that only 16% volume expansion and 70% volume fraction of solid sulfur remaining in the S@HCS/MnOx cathode, superior to the commercial cathode with 40% volume expansion and 5% volume remaining of solid sulfur particles. This is the first reported visualization evidence for the effectiveness of hollow carbon structure in accommodating cathode volume expansion and immobilizing sulfur shuttling. X-ray CT can serve as a powerful in situ tool to trace the active materials and then feedback to the structure design, which helps develop efficient and reliable energy storage systems.
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Oct 2020
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I12-JEEP: Joint Engineering, Environmental and Processing
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Martin T. M.
Pham
,
John J.
Darst
,
Donal P.
Finegan
,
James B.
Robinson
,
Thomas M. M.
Heenan
,
Matt D. R.
Kok
,
Francesco
Iacoviello
,
Rhodri
Owen
,
William Q.
Walker
,
Oxana
Magdysyuk
,
Thomas
Connolley
,
Eric
Darcy
,
Gareth
Hinds
,
Dan J. L.
Brett
,
Paul
Shearing
Diamond Proposal Number(s):
[20903]
Abstract: It remains difficult to detect internal mechanical deformation and gas-induced degradation in lithium-ion batteries, especially outside specialized diagnostics laboratories. In this work, we demonstrate that electrochemical acoustic time-of-flight (EA-ToF) spectroscopy can be used as an insightful and field-deployable diagnostic/prognostic technique to sense the onset of failure. A 210 mAh commercial lithium-ion cell undergoing thermal abuse testing is probed with in situ and operando EA-ToF spectroscopy, together with simultaneous fractional thermal runaway calorimetry (FTRC) and synchrotron X-ray imaging. The combination of X-ray imaging and EA-ToF analysis provides new understanding into the through-plane mechanical deformation in lithium-ion batteries through direct visualisation and the acoustic ToF response. Internal structural changes, such as gas-induced delamination, are identified using EA-ToF spectroscopy due to variations in the attenuation and signal peak shifts. This is corroborated using X-ray imaging, demonstrating EA-ToF spectroscopy as a promising technique for detecting onset of battery failure.
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Jun 2020
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
E01-JEM ARM 200CF
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Jianwei
Li
,
Kit
Mccoll
,
Xuekun
Lu
,
Sanjay
Sathasivam
,
Haobo
Dong
,
Liqun
Kang
,
Zhuangnan
Li
,
Siyu
Zhao
,
Andreas G.
Kafizas
,
Ryan
Wang
,
Dan J. L.
Brett
,
Paul R.
Shearing
,
Furio
Corà
,
Guanjie
He
,
Claire J.
Carmalt
,
Ivan P.
Parkin
Diamond Proposal Number(s):
[24197, 22572]
Abstract: Cost‐effective and environment‐friendly aqueous zinc‐ion batteries (AZIBs) exhibit tremendous potential for application in grid‐scale energy storage systems but are limited by suitable cathode materials. Hydrated vanadium bronzes have gained significant attention for AZIBs and can be produced with a range of different pre‐intercalated ions, allowing their properties to be optimized. However, gaining a detailed understanding of the energy storage mechanisms within these cathode materials remains a great challenge due to their complex crystallographic frameworks, limiting rational design from the perspective of enhanced Zn2+ diffusion over multiple length scales. Herein, a new class of hydrated porous δ‐Ni0.25V2O5.nH2O nanoribbons for use as an AZIB cathode is reported. The cathode delivers reversibility showing 402 mAh g−1 at 0.2 A g−1 and a capacity retention of 98% over 1200 cycles at 5 A g−1. A detailed investigation using experimental and computational approaches reveal that the host “δ” vanadate lattice has favorable Zn2+ diffusion properties, arising from the atomic‐level structure of the well‐defined lattice channels. Furthermore, the microstructure of the as‐prepared cathodes is examined using multi‐length scale X‐ray computed tomography for the first time in AZIBs and the effective diffusion coefficient is obtained by image‐based modeling, illustrating favorable porosity and satisfactory tortuosity.
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Feb 2020
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B18-Core EXAFS
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Diamond Proposal Number(s):
[14239]
Open Access
Abstract: Several nano-sized mixed molybdenum/vanadium oxide monoclinic solid solutions were synthesised using a continuous hydrothermal flow process and studied with a wide range of physical characterization techniques including X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray absorption spectroscopy. The nanomaterials were tested as anodes for Li-ion batteries in the potential range 0.05–3.00 V vs. Li/Li+. Samples with nominal formulas of Mo0.5V0.5O2 and Mo0.33V0.67O2 showed excellent performance, especially at high current rates, due to their highly pseudocapacitive charge storage mechanism. At a specific current of 10 A g−1, Mo0.5V0.5O2 and Mo0.33V0.67O2 showed specific capacities of ca. 200 and 170 mAh g−1, respectively. Mo0.5V0.5O2 also showed good cyclability, with a specific capacity of 480 mAh g−1 after 150 cycles at a specific current of 0.5 A g−1. For cyclic voltammetries conducted at high scan rates, pseudocapacitive charge storage contributed more than 90% to the total charge storage for both samples. The scalability of the synthesis technique and excellent electrochemical performance at high power make these materials promising as negative electrode active materials for Li-ion batteries.
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Aug 2019
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B18-Core EXAFS
E01-JEM ARM 200CF
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Ruoyu
Xu
,
Liqun
Kang
,
Johannes
Knossalla
,
Jerrik
Mielby
,
Qiming
Wang
,
Bolun
Wang
,
Junrun
Feng
,
Guanjie
He
,
Yudao
Qin
,
Jijia
Xie
,
Ann-christin
Swertz
,
Qian
He
,
Søren
Kegnæs
,
Dan J.l.
Brett
,
Ferdi
Schüth
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[206191, 15151]
Abstract: Nanostructured carbons with different pore geometries are prepared with a liquid-free nanocasting method. The method uses gases instead of liquid to disperse carbon precursor, leach templates and remove impurities, minimizing synthetic procedures and the use of chemicals. The method is universal and demonstrated by the synthesis of 12 different porous carbons with various template sources. The effects of pore geometries in catalysis can be isolated and investigated. Two of the resulted materials with different pore geometries are studied as supports for Ru clusters in the hydrogenolysis of 5-hydroxymethylfurfural (HMF) and electrochemical hydrogen evolution (HER). The porous carbon supported Ru catalysts outperform commercial ones in both reactions. It was found that Ru on bottle-neck pore carbon shows highest yield in hydrogenolysis of HMF to 2,5-dimethylfuran (DMF) due to a better confinement effect. A wide temperature operation window from 110 °C to 140 °C, with over 75% yield and 98% selectivity of DMF has been achieved. Tubular pores enable fast charge transfer in electrochemical HER, requiring only 16 mV overpotential to reach current density of 10 mA cm.
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Jan 2019
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[11539]
Open Access
Abstract: Lithium-based rechargeable batteries such as lithium-ion (Li-ion), lithium-sulfur (Li-S), and lithium-air (Li-air) cells typically consist of heterogenous porous electrodes. In recent years, there has been growing interest in the use of in-situ and operando micro-CT to capture their physical and chemical states in 3D. The development of in-situ electrochemical cells along with recent improvements in radiation sources have expanded the capabilities of micro-CT as a technique for longitudinal studies on operating mechanisms and degradation. In this paper, we present an overview of the capabilities of the current state of technology and demonstrate novel tomography cell designs we have developed to push the envelope of spatial and temporal resolution while maintaining good electrochemical performance. A bespoke PEEK in-situ cell was developed, which enabled imaging at a voxel resolution of ca. 230 nm and permitted the identification of sub-micron features within battery electrodes. To further improve the temporal resolution, future work will explore the use of iterative reconstruction algorithms, which require fewer angular projections for a comparable reconstruction.
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Nov 2018
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[16110]
Abstract: Lithium sulfur (Li-S) batteries have great potential as a successor to Li-ion batteries but their commercialization has been complicated by a multitude of issues stemming from their complex multi-phase chemistry. In-situ X-ray tomography investigations enable direct observations to be made about a battery, providing unprecedented insight into the microstructural evolution of the sulfur cathode and shedding light on the reaction kinetics of the sulfur phase. Here, for the first time, the morphology of a sulfur cathode was visualized in 3D as a function of state of charge at high temporal and spatial resolution. Whilst elemental sulfur was originally well dispersed throughout the uncycled cathode, subsequent charging resulted in the formation of sulfur clusters along preferred orthogonal orientations in the cathode. The electrical conductivity of the cathode was found not to be rate-limiting, suggesting the need to optimize the loading of conductive carbon additives. The carbon and binder domain, and surrounding bulk pore phase were visualized in the in-situ cell, and contrast changes within both phases were successfully extracted. The applications of this technique are not limited to microstructural and morphological characterization, and the volumetric data can serve as a valuable input for true 3D computational modelling of Li-S batteries.
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Aug 2018
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B18-Core EXAFS
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Diamond Proposal Number(s):
[10306]
Open Access
Abstract: Comprehensive identification of the phases and atomic configurations of bimetallic nanoparticle catalysts are critical in understanding structure-properties relationships in catalysis. However, control of the structure, whilst retaining the same composition, is challenging. Here, the same carbon supported Pt3Sn catalyst is annealed under air, Ar and H2 resulting in variation of the extent of alloying of the two components. The atmosphere-induced extent of alloying is characterised using a variety of methods including TEM, XRD, XPS, XANES, and EXAFS and is defined as the fraction of Sn present as Sn0 (XPS and XANES) or the ratio of the calculated composition of the bimetallic particle to the nominal composition according to the stoichiometric ratio of the preparation (TEM, XRD, and EXAFS) . The values obtained depend on the structural method used, but the trend air < Ar < H2 annealed samples is consistent. These results are then used to provide insights regarding the electrocatalytic activity of Pt3Sn catalysts for CO, methanol, ethanol, and 1-butanol oxidation and the roles of alloyed Sn and SnO2.
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Apr 2018
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