Antonis Vamvakeros

Dr. Antonis Vamvakeros

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 January 2020 in Journal of Synchrotron Radiation
Verified
Journal Article
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GVGavin B. M. Vaughan
Gavin B. M. Vaughan
RBRobert Baker
Robert Baker
RBRaymond Barret
Raymond Barret
JBJulien Bonnefoy
Julien Bonnefoy
TBThomas Buslaps
Thomas Buslaps
MMMarco Di Michiel
Marco Di Michiel
ID15A is a newly refurbished beamline at the ESRF devoted to operando and time-resolved diffraction and imaging, total scattering and diffraction computed tomography. The beamline is optimized for rapid alternation between the different techniques during a single operando experiment in order to collect complementary data on working systems. The high available energy (up to 120 keV) means that even bulky and highly absorbing systems may be studied. The beamline is equipped with optimized focusing optics and a photon-counting CdTe pixel detector, allowing for both unprecedented data quality at high energy and for very rapid triggered experiments. A large choice of imaging detectors and ancillary probes and sample environments is also available.

31 January 2020 in Nature Communications
Verified
Journal Article
Open access
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DFDonal Finegan
Donal Finegan
AVAntonis Vamvakeros
Antonis Vamvakeros
CTChun Tan
Chun Tan
Thomas M.M. HeenanThomas M.M. Heenan
Thomas M.M. Heenan
SDSohrab R. Daemi
Sohrab R. Daemi
KSKandler Smith
Kandler Smith
The performance of lithium ion electrodes is hindered by unfavorable chemical heterogeneities that pre-exist or develop during operation. Time-resolved spatial descriptions are needed to understand the link between such heterogeneities and a cell’s performance. Here, operando high-resolution X-ray diffraction-computed tomography is used to spatially and temporally quantify crystallographic heterogeneities within and between particles throughout both fresh and degraded LixMn2O4 electrodes. This imaging technique facilitates identification of stoichiometric differences between particles and stoichiometric gradients and phase heterogeneities within particles. Through radial quantification of phase fractions, the response of distinct particles to lithiation is found to vary; most particles contain localized regions that transition to rock salt LiMnO2 within the first cycle. Other particles contain monoclinic Li2MnO3 near the surface and almost pure spinel LixMn2O4 near the core. Following 150 cycles, concentrations of LiMnO2 and Li2MnO3 significantly increase and widely vary between particles.

13 May 2019 in Nano Letters
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Journal Article
Closed access
DFDonal Finegan
Donal Finegan
AVAntonis Vamvakeros
Antonis Vamvakeros
LCLei Cao
Lei Cao
CTChun Tan
Chun Tan
Thomas M.M. HeenanThomas M.M. Heenan
Thomas M.M. Heenan
CBChunmei Ban
Chunmei Ban

2 April 2019 in Nature Communications
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Journal Article
Open access
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TLTao Li
Tao Li
Thomas M.M. HeenanThomas M.M. Heenan
Thomas M.M. Heenan
MRMohamad Fairus Rabuni
Mohamad Fairus Rabuni
BWBo Wang
Bo Wang
NFNicholas M. Farandos
Nicholas M. Farandos
KLKang Li
Kang Li
Ceramic fuel cells offer a clean and efficient means of producing electricity through a variety of fuels. However, miniaturization of cell dimensions for portable device application remains a challenge, as volumetric power densities generated by readily-available planar/tubular ceramic cells are limited. Here, we demonstrate a concept of ‘micro-monolithic’ ceramic cell design. The mechanical robustness and structural integrity of this design is thoroughly investigated with real-time, synchrotron X-ray diffraction computed tomography, suggesting excellent thermal cycling stability. The successful miniaturization results in an exceptional power density of 1.27 W cm−2 at 800 °C, which is among the highest reported. This holistic design incorporates both mechanical integrity and electrochemical performance, leading to mechanical property enhancement and representing an important step toward commercial development of portable ceramic devices with high volumetric power (>10 W cm−3), fast thermal cycling and marked mechanical reliability.

12 November 2018 in Nature Communications
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Journal Article
Open access
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AVAntonis Vamvakeros
Antonis Vamvakeros
SJS. D. M. Jacques
S. D. M. Jacques
MMM. Di Michiel
M. Di Michiel
DMD. Matras
D. Matras
VMVesna Middelkoop
Vesna Middelkoop
ABAndrew M. Beale
Andrew M. Beale
We report the results from the first 5D tomographic diffraction imaging experiment of a complex Ni–Pd/CeO2–ZrO2/Al2O3 catalyst used for methane reforming. This five-dimensional (three spatial, one scattering and one dimension to denote time/imposed state) approach enabled us to track the chemical evolution of many particles across the catalyst bed and relate these changes to the gas environment that the particles experience. Rietveld analysis of some 2 × 106 diffraction patterns allowed us to extract heterogeneities in the catalyst from the Å to the nm and to the μm scale (3D maps corresponding to unit cell lattice parameters, crystallite sizes and phase distribution maps respectively) under different chemical environments. We are able to capture the evolution of the Ni-containing species and gain a more complete insight into the multiple roles of the CeO2-ZrO2 promoters and the reasons behind the partial deactivation of the catalyst during partial oxidation of methane.

1 October 2019 in Journal of CO2 Utilization
Verified
Journal Article
Closed access
VMVesna Middelkoop
Vesna Middelkoop
AVAntonis Vamvakeros
Antonis Vamvakeros
DWDieter de Wit
Dieter de Wit
SJSimon D.M. Jacques
Simon D.M. Jacques
SDSimge Danaci
Simge Danaci
ABAndrew M. Beale
Andrew M. Beale