B18-Core EXAFS
E01-JEM ARM 200CF
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Zhangxiang
Hao
,
Jie
Chen
,
Xuekun
Lu
,
Liqun
Kang
,
Chun
Tan
,
Ruoyu
Xu
,
Lixia
Yuan
,
Dan J.l.
Brett
,
Paul R.
Shearing
,
Feng Ryan
Wang
,
Yunhui
Huang
Diamond Proposal Number(s):
[19072, 19246]
Open Access
Abstract: Despite progress of functionalized separator in preventing the shuttle effect and promoting the sulfur utilization, the precise and non-destructive investigation of structure-function-performance associativity remains limited so far in Li-S batteries. Here, we build consecutive multiscale analysis via combining X-ray absorption fine structure (XAFS) and X-ray computational tomography (CT) techniques to precisely visit the structure-function-performance relationship. XAFS measurement offers the atomic scale changes in the chemical structure and environment. Moreover, a non-destructive technique of X-ray CT proves the functionalized separator role for microscopic scale, which is powerful chaining to bridge the chemical structures of the materials with the overall performance modulation of cells. Benefiting from this consecutive multiscale analysis, we report that the uniform doping of Sr2+ into the perovskite LaMnO3-δ material changes the Mn oxidation states and conductivity (chemical structure), leading to effective lithium polysulfide trapping and accelerated sulfur redox (separator function), and resulting in outstanding cell performance.
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Apr 2022
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B07-B-Versatile Soft X-ray beamline: High Throughput
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Diamond Proposal Number(s):
[29340]
Abstract: The development of low-cost, robust and efficient non-noble metal electrocatalysts is still a pursuit for the hydrogen evolution reaction (HER). Herein, a self-standing electrocatalyst, Ni2P/CoP nanosheet, was fabricated directly on three-dimensional Ni foams by two facile steps, which illustrated both high activity and stability for HER in different electrolytes. Benefiting from the porous structures of nanosheets with large specific surface area and the hybrid Ni2P/CoP, the as-prepared electrocatalyst presented remarkable HER with overpotentials of 65.2 mV and 87.8 mV to reach a current density of -10 mA cm-2 in neutral and alkaline media, respectively. Density function theory calculations revealed a lower activation energy of water dissociation and efficient HER steps of hybrid Ni2P/CoP nanosheets compared with mono CoP. The self-standing electrocatalyst maintained excellent chemical stability. Additionally, the HER process in domestic wastewater was realized with more impressive performance by using Ni2P/CoP nanosheets compared with commercial Pt/C. Hydrogen was continuously generated for 20 h in mildly alkaline dishwashing wastewater. This work provides a feasible way to fabricate non-noble metal and self-standing hybrid bimetallic phosphides for HER in neutral and alkaline media, showing great potential for efficient hydrogen production by re-utilizing wastewater resources.
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Apr 2022
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Ralf F.
Ziesche
,
Jennifer
Hack
,
Lara
Rasha
,
Maximilian
Maier
,
Chun
Tan
,
Thomas M. M.
Heenan
,
Henning
Markötter
,
Nikolay
Kardjilov
,
Ingo
Manke
,
Winfred
Kockelmann
,
Dan J. L.
Brett
,
Paul R.
Shearing
Open Access
Abstract: In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings. This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs.
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Mar 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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William Q.
Walker
,
Kylie
Cooper
,
Peter
Hughes
,
Ian
Doemling
,
Mina
Akhnoukh
,
Sydney
Taylor
,
Jacob
Darst
,
Julia
Billman
,
Matthew
Sharp
,
David
Petrushenko
,
Rhodri
Owen
,
Martin
Pham
,
Thomas
Heenan
,
Alexander
Rack
,
Oxana
Magdysyuk
,
Thomas
Connolley
,
Dan
Brett
,
Paul
Shearing
,
Donal
Finegan
,
Eric
Darcy
Diamond Proposal Number(s):
[24112, 20903, 17641]
Abstract: Consideration of thermal runaway heat output variability is paramount for the development of safe lithium-ion battery assemblies. This study utilizes data gathered from fractional thermal runaway calorimetry (FTRC) experiments to conduct a comparative analysis of thermal runaway heat output for three cell formats (18650, 21700, and 33600) as a function of trigger method (heaters, internal short-circuiting device, and nail penetration). The analysis is based on comparisons for the calculated total energy yield, fractional energy yield, heat rate, and heat flux. This study reveals that nail penetration tends to result in higher thermal runaway heat output for larger cells (21700 & 33600); these experiments also tended to result in higher fractions of the total energy being released through the cell body. The smaller cells (18650) did not appear to have significant variation in heat output as a function of trigger method. This finding suggests that, for this cell type, worst-case scenario heat output could be achievable in assembly level testing regardless of the utilized trigger method. This study also demonstrates successful translation of FTRC results, as recorded in the Battery Failure Databank, into meaningful analysis that breaks down the influence of specific conditions on thermal runaway heat output.
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Mar 2022
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Abstract: Advanced batteries are critical to achieving net zero and are proposed within decarbonization strategies for transport and grid-scale applications, alongside their ubiquitous application in consumer devices. Immense progress has been made in lithium battery technology in recent years, but significant challenges remain and new development strategies are required to improve performance, fully exploit power density capacities, utilize sustainable resources, and lower production costs. Suitable characterization techniques are crucial for understanding, inter alia, three-dimensional (3D) diffusion processes and formation of passivation layers or dendrites, which can lead to drastic capacity reduction and potentially to hazardous short circuiting. Studies of such phenomena typically utilize 2D or 3D imaging techniques, providing locally resolved information. 3D X-ray imaging is a widely used standard method, while time-lapse (4D) tomography is increasingly required for understanding the processes and transformations in an operational battery. Neutron imaging overcomes some of the limitations of X-ray tomography for battery studies. Notably, the high visibility of neutrons for light-Z elements, in particular hydrogen and lithium, enables the direct observation of lithium diffusion, electrolyte consumption, and gas formation in lithium batteries. Neutron imaging as a non-destructive analytical tool has been steadily growing in many disciplines as a result of improvements to neutron detectors and imaging facilities, providing increasingly higher spatial and temporal resolutions. Further, ongoing developments in diffraction imaging for mapping the structural and microstructural properties of battery components make the use of neutrons increasingly attractive. Here, we provide an overview of neutron imaging techniques, generally outlining advances and limitations for studies on batteries and reviewing imaging studies of lithium batteries. We conclude with an outlook on development methods in the field and discuss their potential and significance for future battery research.
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Jan 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Matt
Sharp
,
John
Darst
,
Peter
Hughes
,
Julia
Billman
,
Martin
Pham
,
David
Petrushenko
,
Thomas
Heenan
,
Rhodri
Jervis
,
Rhodri Ellis
Owen
,
Drasti
Patel
,
Wenjia
Du
,
Harry
Michael
,
Alexander
Rack
,
Oxana
Magdysyuk
,
Thomas
Connolley
,
Dan
Brett
,
Gareth
Hinds
,
Matthew
Keyser
,
Eric
Darcy
,
Paul
Shearing
,
William Q.
Walker
,
Donal
Finegan
Diamond Proposal Number(s):
[24112, 20903, 17641]
Open Access
Abstract: Thermal runaway of lithium-ion batteries can involve various types of failure mechanisms each with their own unique characteristics. Using fractional thermal runaway calorimetry and high-speed radiography, the response of three different geometries of cylindrical cell (18650, 21700, and D-cell) to different abuse mechanisms (thermal, internal short circuiting, and nail penetration) are quantified and statistically examined. Correlations between the geometry of cells and their thermal behavior are identified, such as increasing heat output per amp-hour (kJ Ah-1) of cells with increasing cell diameter during nail penetration. High-speed radiography reveals that the rate of thermal runaway propagation within cells is generally highest for nail penetration where there is a relative increase in rate of propagation with increasing diameter, compared to thermal or internal short-circuiting abuse. For a given cell model tested under the same conditions, a distribution of heat output is observed with a trend of increasing heat output with increased mass ejection. Finally, internal temperature measurements using thermocouples embedded in the penetrating nail are shown to be unreliable thus demonstrating the need for care when using thermocouples where the temperature is rapidly changing. All data used in this manuscript are open access through the NREL and NASA Battery Failure Databank.
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Jan 2022
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I11-High Resolution Powder Diffraction
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Andrew Stephen
Leach
,
Alice
Llewellyn
,
Chao
Xu
,
Chun
Tan
,
Thomas M. M.
Heenan
,
Alex
Dimitrijevic
,
Karin
Kleiner
,
Clare P.
Grey
,
Dan J. L.
Brett
,
Chiu C.
Tang
,
Paul R.
Shearing
,
Rhodri
Jervis
Diamond Proposal Number(s):
[22498, 24122]
Open Access
Abstract: Understanding the performance of commercially relevant cathode materials for lithium-ion (Li-ion) batteries is vital to realize the potential of high-capacity materials for automotive applications. Of particular interest is the spatial variation of crystallographic behavior across (what can be) highly inhomogeneous electrodes. In this work, a high-resolution X-ray diffraction technique was used to obtain operando transmission measurements of Li-ion pouch cells to measure the spatial variances in the cell during electrochemical cycling. Through spatially resolved investigations of the crystallographic structures, the distribution of states of charge has been elucidated. A larger portion of the charging is accounted for by the central parts, with the edges and corners delithiating to a lesser extent for a given average electrode voltage. The cells were cycled to different upper cutoff voltages (4.2 and 4.3 V vs. graphite) and C-rates (0.5, 1, and 3C) to study the effect on the structure of the NMC811 cathode. By combining this rapid data collection method with a detailed Rietveld refinement of degraded NMC811, the spatial dependence of the degradation caused by long-term cycling (900 cycles) has also been shown. The variance shown in the pristine measurements is exaggerated in the aged cells with the edges and corners offering an even lower percentage of the charge. Measurements collected at the very edge of the cell have also highlighted the importance of electrode alignment, with a misalignment of less than 0.5 mm leading to significantly reduced electrochemical activity in that area.
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Jan 2022
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B18-Core EXAFS
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Diamond Proposal Number(s):
[24178]
Open Access
Abstract: Nickel-rich cathodes (LiNixMnyCo1-x-yO2, x > 0.6) permit higher energy in lithium-ion rechargeable batteries but suffer from accelerated degradation at potentials above 4.1 V versus Li/Li+. Here, we present a proof-of-concept in situ pouch cell and methodology for correlative 2D synchrotron transmission X-ray microscopy with 3D lab-based micro-CT. XANES analysis of the TXM data enables tracking of Ni edge energy within and between the polycrystalline NMC811 particles embedded in the operating electrode through its initial delithiation. By using edge energy as a proxy, state-of-charge heterogeneities can be tracked at the nanoscale, revealing the role of cracked particles as potential nucleation points for failure and highlighting the challenges in achieving uniform (de-)lithiation. We propose, in future work, to leverage the pouch cell design presented here for longitudinal TXM-XANES studies of nickel-rich cathodes across multiple cycles and operating variables and investigate the effect of dopants and microstructural optimization in mitigating degradation.
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Nov 2021
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I14-Hard X-ray Nanoprobe
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Diamond Proposal Number(s):
[20841, 23858]
Abstract: Battery electrodes are composed of many millions of particles. Lithium-ions entering and leaving these particles charge and discharge the battery. Defects in the particles reduce the battery’s capacity. This would impact electric vehicle range in automotive applications, for example, requiring drivers to stop more frequently to recharge. Therefore, it is crucial to investigate which particles
contain defects, whether different types of defects exist, and how we might prevent them forming.
Electrode particles are spheres with diameters on the order of tens of microns (smaller than a human hair). Due to their small size, investigating their properties requires high-resolution specialist facilities, such as those at the Hard X-Ray Nanoprobe beamline (I14) at Diamond Light Source. The defects have complex origins, requiring the use of multiple investigation techniques at once, for which I14 was specifically designed.
Batteries that are nickel-based (around 80%), with manganese and cobalt making up the other 20%, are of particular interest to the automotive industry. By analysing various particles at I14 and comparing the results with data collected in the labs at University College London (UCL), researchers found a correlation between the manganese content and the ordering of the particle’s crystals. However, they attributed the amount of cracking within the particle to the crystal orientations. Preventing the manganese from leaving the particles may maintain the crystal ordering. Aligning the crystals, or making larger single crystals, may avoid - or at least delay - particle cracking. Overcoming these issues would allow electric vehicles to travel for longer before needing to recharge.
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Jul 2021
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I20-EDE-Energy Dispersive EXAFS (EDE)
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Andrew S.
Leach
,
Jennifer
Hack
,
Monica
Amboage
,
Sofia
Diaz-Moreno
,
Haoliang
Huang
,
Patrick L.
Cullen
,
Martin
Wilding
,
Emanuele
Magliocca
,
Thomas
Miller
,
Christopher
Howard
,
Daniel
Brett
,
Paul
Shearing
,
Paul F.
Mcmillan
,
Andrea E.
Russell
,
Rhodri
Jervis
Diamond Proposal Number(s):
[22008, 15650]
Open Access
Abstract: A polymer electrolyte fuel cell (PEFC) has been designed to allow operando X-ray absorption spectroscopy (XAS) measurements of catalysts. The cell has been developed to operate under standard fuel cell conditions, with elevated temperatures and humidification of the gas-phase reactants, both of which greatly impact the catalyst utilisation. X-ray windows in the endplates of the cell facilitate collection of XAS spectra during fuel cell operation while maintaining good compression in the area of measurement. Results of polarisation curves and cyclic voltammograms (CVs) showed that the operando cell performs well as a fuel cell, while also providing XAS data of suitable quality for robust XANES analysis. The cell has produced comparable XAS results when performing a cyclic voltammogram to an established in situ cell when measuring the Pt LIII edge. Similar trends of Pt oxidation, and reduction of the formed Pt oxide, have been presented with a time resolution of 5 seconds for each spectrum, paving the way for time-resolved spectral measurements of fuel cell catalysts in a fully-operating fuel cell.
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May 2021
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