Boron activity in the inactive Li2MnO3 cathode material

Özkendir, Osman Murat; Harfouche, Messaoud; Ulfat, İntikhab; Kaya, C.; Çelik, Gültekin; Ateş, Şule; Aktaş, Sevda; Bavegar, Hadi; Çolak, Tuğba Kuru

doi:10.1016/j.elspec.2019.06.011

Cited by 7 publications

(2 citation statements)

References 11 publications

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“…The differences between the XANES (Zn K-edge and O K-edge) for ZnO nanostructures and ZnO bulk were compared with the theoretically calculated spectra for ZnO surfaces and bulk, and it was concluded that the difference in the XANES was mainly due to local geometry differences around the photoabsorbing sites (Š ipr & Rocca, 2011). Recently, the activity of B in inactive Li 2 MnO 3 cathode material has been investigated by some of us using XRD and XAFS techniques (Ozkendir et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy

Erat¹,

Özkendir²,

Yıldırımcan³

et al. 2021

J Synchrotron Radiat

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X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectra were recorded to investigate the electronic structure and local crystal structure of ZnO and ZnO:B powders produced via hydrothermal synthesis. ZnO and ZnO:B grow as micrometre-scale rods with hexagonal shape, as confirmed by scanning electron microscopy micrographs. The number of broken ZnO:B rods increases with increasing B concentration, as observed in the images, due to B atoms locating in between the Zn and O atoms which weakens and/or breaks the Zn–O bonds. However, no disorder within the crystallographic structure of ZnO upon B doping is observed from X-ray diffraction results, which were supported by EXAFS results. To determine the atomic locations of boron atoms in the crystal structure and their influence on the zinc atoms, EXAFS data were fitted with calculated spectra using the crystal structure parameters obtained from the crystallographic analysis of the samples. EXAFS data fitting and complementary k-weight analysis revealed the positions of the B atoms – their positions were determined to be in between the Zn and O atoms.

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Section: Introductionmentioning

confidence: 99%

Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy

Erat¹,

Özkendir²,

Yıldırımcan³

et al. 2021

J Synchrotron Radiat

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“…Various fields of research have exploited this instrument since its opening to users (July 2018): environmental science (Morales-Pe ´rez et al, 2021;El-Hasan et al, 2021;Shaltout et al, 2021), energy storage (Khan et al, 2021;Altin et al, 2021), materials science (Jamil et al, 2021;Erat et al, 2021;Filipponi et al, 2020;Altaf et al, 2020;Ozkendir et al, 2019Ozkendir et al, , 2020Bayri et al, 2020), as well as cultural heritage (Lorentz et al, 2020) and chemistry and catalysis (Hamo et al, 2021;Barzgar Vishlaghi et al, 2021;Amirzhanova et al, 2019;Bac et al, 2019;Uzunok et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Emergence of the first XAFS/XRF beamline in the Middle East: providing studies of elements and their atomic/electronic structure in pluridisciplinary research fields

Harfouche¹,

Abdellatief²,

Momani³

et al. 2022

J Synchrotron Rad

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XAFS/XRF is a general-purpose absorption spectroscopy beamline at the Synchrotron-light for Experimental Science and Applications in the Middle East (SESAME), Jordan. Herein, its optical layout is presented along with its powerful capabilities in collecting absorption and fluorescence spectra within a wide energy range (4.7–30 keV). The beamline is equipped with a conventional fixed-exit double-crystal monochromator that allows the collection of an X-ray absorption spectrum within a few minutes in step-by-step mode. An on-the-fly scanning mode will be implemented shortly where the acquisition time will be reduced to less than a minute per scan. The full automation of the beamline allows performing successive measurements under different conditions. The different experimental setups and special features available to users are reported. Examples of XRF and XAFS measurements are presented, showing the performance of the beamline under different standard conditions.

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Heavy Fluorination via Ion Exchange Achieves High‐Performance Li–Mn–O–F Layered Cathode for Li‐Ion Batteries

Cao

et al. 2021

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Lithium‐excess manganese layered oxide Li2MnO3, attracts much attention as a cathode in Li‐ion batteries, due to the low cost and the ultrahigh theoretical capacity (≈460 mA h g−1). However, it delivers a low reversible practical capacity (<200 mA h g−1) due to the irreversible oxygen redox at high potentials (>4.5 V). Herein, heavy fluorination (9.5%) is successfully implemented in the layered anionic framework of a Li–Mn–O–F (LMOF) cathode through a unique ion‐exchange route. F substitution with O stabilizes the layered anionic framework, completely inhibits the O2 evolution during the first cycle, and greatly enhances the reversibility of oxygen redox, delivering an ultrahigh reversible capacity of 389 mA h g−1, which is 85% of the theoretical capacity of Li2MnO3. Moreover, it also induces a thin spinel shell coherently forming on the particle surface, which greatly improves the surface structure stability, making LMOF exhibit a superior cycling stability (a capacity retention of 91.8% after 120 cycles at 50 mA g−1) and excellent rate capability. These findings stress the importance of stabilizing the anionic framework in developing high‐performance low‐cost cathodes for next‐generation Li‐ion batteries.

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Boron activity in the inactive Li2MnO3 cathode material

Cited by 7 publications

References 11 publications

Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy

Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy

Emergence of the first XAFS/XRF beamline in the Middle East: providing studies of elements and their atomic/electronic structure in pluridisciplinary research fields

Heavy Fluorination via Ion Exchange Achieves High‐Performance Li–Mn–O–F Layered Cathode for Li‐Ion Batteries

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