On the Beneficial Effect of MgCl2 as Electrolyte Additive to Improve the Electrochemical Performance of Li4Ti5O12 as Cathode in Mg Batteries

Magnesium batteries are a promising technology for a new generation of energy storage for portable devices. Attention should be paid to electrolyte and electrode material development in order to develop rechargeable Mg batteries. In this study, we report the use of the spinel lithium titanate or Li4Ti5O12 (LTO) as an active electrode for Mg2+-ion batteries. The theoretical capacity of LTO is 175 mA h g−1, which is equivalent to an insertion reaction with 1.5 Mg2+ ions. The ability to enhance the specific capacity of LTO is of practical importance. We have observed that it is possible to increase the capacity up to 290 mA h g−1 in first discharge, which corresponds to the reaction with 2.5 Mg2+ ions. The addition of MgCl2·6H2O to the electrolyte solutions significantly improves their electrochemical performance and enables reversible Mg deposition. Ex-situ X-ray diffraction (XRD) patterns reveal little structural changes, while X-ray photoelectron spectrometer (XPS) (XPS) measurements suggest Mg reacts with LTO. The Ti3+/Ti4+ ratio increases with the amount of inserted magnesium. The impedance spectra show the presence of a semicircle at medium-low frequencies, ascribable to Mg2+ ion diffusion between the surface film and LTO. Further experimental improvements with exhaustive control of electrodes and electrolytes are necessary to develop the Mg battery with practical application.

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Battery research using synchrotron powder X-ray diffraction

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090482 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C951-C951

Author(s):

Qinfen Gu ◽

Helen Brand ◽

Justin Kimpton

Keyword(s):

Structural Changes ◽

Electrode Materials ◽

Rechargeable Batteries ◽

Ex Situ ◽

Insertion Reaction ◽

Clear Understanding ◽

X Ray Diffraction ◽

X Ray ◽

User Groups

Research and development of rechargeable batteries is critical to meet the worldwide demand for clean and sustainable energy collection and storage. A vital part of this research is to get clear understanding of how the crystal structures of electrode materials affect the the resulting properties of the batteries. As structural changes in both the anode and cathode materials play an important role in overall battery performance, synchrotron powder X-ray diffraction (PXRD), with high beam flux and resolution, is an extremely useful tool for studying the battery both in-situ and ex-situ. Several simple in-situ cell designs have been designed for synchrotron PXRD measurement. The cell is available for researchers in the field of battery research. The effectiveness and simplicity of the cell design have been demonstrated at Powder Diffraction Beamline at Australian Synchrotron for several user groups. Case studies of analysis of the lithium insertion reaction for Li0.18Sr0.66Ti0.5Nb0.5O3 defect perovskite [1], crystal structure of Li4Ti5O12–xBrx electrode material [2] and LiNi1/3Mn1/3Co1/3O2 (NMC) as a new synthesized cathode material [3] will be discussed, respectively.

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Structural Changes in French VF Treatment Wetland Porous Media during the Rest Period: An Ex Situ Study Using X-ray Tomography

Water ◽

10.3390/w13030389 ◽

2021 ◽

Vol 13 (3) ◽

pp. 389

Author(s):

German Dario Martinez-Carvajal ◽

Laurent Oxarango ◽

Jérôme Adrien ◽

Pascal Molle ◽

Nicolas Forquet

Keyword(s):

Porous Media ◽

Structural Changes ◽

Rest Period ◽

Treatment Wetlands ◽

Ex Situ ◽

Initial Value ◽

Treatment Wetland ◽

X Ray ◽

The Impact ◽

Deposit Layer

Clogging constitutes a major operational issue for treatment wetlands. The rest period is a key feature of French Vertical Flow (VF) treatment wetlands and serves to mitigate clogging. An ex-situ drying experiment was performed to mimic the rest period and record structural changes in the porous media using X-ray Computed Tomography (CT). Samples containing the deposit and gravel layers of a first stage French VF treatment wetland were extracted and left to dry in a control environment. Based on CT scans, three phases were identified (voids, biosolids, and gravels). The impact of the rest period was assessed by means of different pore-scale variables. Ultimately, the volume of biosolids had reduced to 58% of its initial value, the deposit layer thickness dropped to 68% of its initial value, and the void/biosolid specific surface area ratio increased from a minimum value of 1.1 to a maximum of 4.2. Cracks greater than 3 mm developed at the uppermost part of the deposit layer, while, in the gravel layer, the rise in void volume corresponds to pores smaller than 2 mm in diameter. Lastly, the air-filled microporosity is estimated to have increased by 0.11 v/v.

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Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03312e ◽

2017 ◽

Vol 19 (31) ◽

pp. 20867-20880 ◽

Cited By ~ 27

Author(s):

David C. Bock ◽

Christopher J. Pelliccione ◽

Wei Zhang ◽

Janis Timoshenko ◽

K. W. Knehr ◽

...

Keyword(s):

Electron Microscopy ◽

Structural Changes ◽

Ex Situ ◽

X Ray Diffraction ◽

X Ray ◽

Size Dependent ◽

Transmission Electron ◽

Dependent Behavior ◽

X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

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Centrifugally Spun α-Fe2O3/TiO2/Carbon Composite Fibers as Anode Materials for Lithium-Ion Batteries

Applied Sciences ◽

10.3390/app9194032 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4032 ◽

Cited By ~ 5

Author(s):

Luis Zuniga ◽

Gabriel Gonzalez ◽

Roberto Orrostieta Chavez ◽

Jason C. Myers ◽

Timothy P. Lodge ◽

...

Keyword(s):

Electron Microscopy ◽

Electrochemical Performance ◽

Lithium Ion Batteries ◽

Specific Capacity ◽

Lithium Ion ◽

Composite Fiber ◽

Carbon Composite ◽

Composite Fibers ◽

X Ray ◽

Binder Free

We report results on the electrochemical performance of flexible and binder-free α-Fe2O3/TiO2/carbon composite fiber anodes for lithium-ion batteries (LIBs). The composite fibers were produced via centrifugal spinning and subsequent thermal processing. The fibers were prepared from a precursor solution containing PVP/iron (III) acetylacetonate/titanium (IV) butoxide/ethanol/acetic acid followed by oxidation at 200 °C in air and then carbonization at 550 °C under flowing argon. The morphology and structure of the composite fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). These ternary composite fiber anodes showed an improved electrochemical performance compared to the pristine TiO2/C and α-Fe2O3/C composite fiber electrodes. The α-Fe2O3/TiO2/C composite fibers also showed a superior cycling performance with a specific capacity of 340 mAh g−1 after 100 cycles at a current density of 100 mA g−1, compared to 61 mAh g−1 and 121 mAh g−1 for TiO2/C and α-Fe2O3/C composite electrodes, respectively. The improved electrochemical performance and the simple processing of these metal oxide/carbon composite fibers make them promising candidates for the next generation and cost-effective flexible binder-free anodes for LIBs.

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Boosting the Rate and Cycling Performance of β-LixV2O5 Nanorods for Li Ion Battery by Electrode Surface Decoration

10.26434/chemrxiv.9791540.v1 ◽

2019 ◽

Author(s):

Panpan Wang ◽

Yue Du ◽

Baoyou Zhang ◽

Yanxin Yao ◽

Yuchen Xiao ◽

...

Keyword(s):

Electrochemical Performance ◽

Current Density ◽

Electrochemical Impedance ◽

Electronic Conductivity ◽

Specific Capacity ◽

Rate Capability ◽

Lithium Ion ◽

Ex Situ ◽

Practical Application ◽

Surface Decoration

The β-phase lithium vanadium oxide bronze (β-LixV2O5) with high theoretic specific capacity up to 440 mAh g-1 is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of β-LixV2O5 cathode using both reduced oxide graphene and ionic conductor LaPO4, which significantly promotes the electronic transfer and Li+ diffusion rate, respectively. As a result, the rGO/LaPO4/LixV2O5 composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g-1 with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g-1, and acceptable specific capacity of 170.3 mAh g-1 at high current density of 400 mA g-1. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, ex-situ X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our results provide an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.

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Preparation of Nano-spherical Iron Phosphate by Hydrothermal Method and Its Application as the Precursor of Lithium Iron Phosphate

Journal of Electrochemical Energy Conversion and Storage ◽

10.1115/1.4047223 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Ju Guo ◽

Fuyong Wu

Keyword(s):

Particle Size ◽

Electron Microscope ◽

Electrochemical Performance ◽

Hydrothermal Method ◽

Carbon Coating ◽

Specific Capacity ◽

Iron Phosphate ◽

X Ray ◽

Spherical Morphology ◽

Charge Discharge

Abstract First, nano-spherical iron phosphate was prepared using the hydrothermal method. Then, the carbothermal reduction method was applied to synthesize the LiFePO4/C composite material capable of good carbon coating effect with the prepared nano-spherical iron phosphate as a precursor. By means of scanning electron microscope, transmission electron microscope, Zeta potentiometer, inductively coupled plasma spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical testing, and other methods, the material was characterized and tested for its morphology, particle size, composition, structure, and electrochemical performance. According to the test results, when the initial mass concentration of Fe3+ in the reaction solution is 2%, the amount of N and S impurity is merely 19 and 27 ppm, respectively. In the meantime, particle size is small, with a range of roughly 50–100 nm, and a spherical morphology is shown. The synthesized LiFePO4/C retains its nano-spherical morphology, which leads to a desirable carbon coating effect and an excellent electrochemical performance. The first charge–discharge specific capacity at 0.1 C rate reached 163.7 and 161.4 mAh/g, the charge–discharge efficiency was 98.6%, and the capacity retention rate at 50 charge–discharge cycles at 1 C rate reached 98.52%.

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Effect of HCl+LiF Etching Process on Electrochemical Performance of Ti3C2

NANO ◽

10.1142/s1793292020500587 ◽

2020 ◽

Vol 15 (05) ◽

pp. 2050058

Author(s):

Yuhua Huang ◽

Weiwei Li ◽

Bingchu Mei ◽

Yu Yang ◽

Zuodong Liu

Keyword(s):

Electrochemical Performance ◽

Photoelectron Spectroscopy ◽

Lithium Fluoride ◽

Specific Capacity ◽

Etching Process ◽

X Ray Diffraction ◽

In Situ Oxidation ◽

X Ray ◽

Scanning Electron

In this paper, the effects of etching temperature and concentrations of hydrochloric acid (HCl) on the exfoliating process and the electrochemical performance of LIBs were systematically explored. The transformation from Ti3AlC2 to Ti3C2 was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectra. The suitable conditions of preparing Ti3C2 MXene though HCl and lithium fluoride (LiF) were obtained. Besides, the in-situ oxidation conditions of Ti3C2 during the etching process were studied. The TiO2/Ti3C2 was beneficial to improve the specific capacity from 125[Formula: see text]mAh[Formula: see text]g[Formula: see text] to 150[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 1 C.

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Enhanced Cycle Stability of Zinc Sulfide Anode for High-Performance Lithium-Ion Storage: Effect of Conductive Hybrid Matrix on Active ZnS

Nanomaterials ◽

10.3390/nano9091221 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1221 ◽

Cited By ~ 3

Author(s):

Quoc Hanh Nguyen ◽

Taehyun Park ◽

Jaehyun Hur

Keyword(s):

Titanium Carbide ◽

Electrochemical Performance ◽

Zinc Sulfide ◽

Amorphous Carbon ◽

Specific Capacity ◽

Lithium Ion ◽

High Energy ◽

Ex Situ ◽

Capacity Retention ◽

Hybrid Matrix

Zinc sulfide (ZnS) nanocrystallites embedded in a conductive hybrid matrix of titanium carbide and carbon, are successfully fabricated via a facile high-energy ball-milling (HEBM) process. The structural and morphological analyses of the ZnS-TiC-C nanocomposites reveal that ZnS and TiC nanocrystallites are homogeneously distributed in an amorphous carbon matrix. Compared with ZnS-C and ZnS composites, the ZnS-TiC-C nanocomposite exhibits significantly improved electrochemical performance, delivering a highly reversible specific capacity (613 mA h g−1 over 600 cycles at 0.1 A g−1, i.e., ~85% capacity retention), excellent long-term cyclic performance (545 mA h g−1 and 467 mA h g−1 at 0.5 A g−1 and 1 A g−1, respectively, after 600 cycles), and good rate capability at 10 A g−1 (69% capacity retention at 0.1 A g−1). The electrochemical performance is significantly improved, primarily owing to the presence of conductive hybrid matrix of titanium carbide and amorphous carbon in the ZnS-TiC-C nanocomposites. The matrix not only provides high conductivity but also acts as a mechanical buffering matrix preventing huge volume changes during prolonged cycling. The lithiation/delithiation mechanisms of the ZnS-TiC-C electrodes are examined via ex situ X-ray diffraction (XRD) analysis. Furthermore, to investigate the practical application of the ZnS-TiC-C nanocomposite, a coin-type full cell consisting of a ZnS-TiC-C anode and a LiFePO4–graphite cathode is assembled and characterized. The cell exhibits excellent cyclic stability up to 200 cycles and a good rate performance. This study clearly demonstrates that the ZnS-TiC-C nanocomposite can be a promising negative electrode material for the next-generation lithium-ion batteries.

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Structural Evolution of MoO3 Thin Films Deposited on Copper Substrates upon Annealing: An X-ray Absorption Spectroscopy Study

Condensed Matter ◽

10.3390/condmat4020041 ◽

2019 ◽

Vol 4 (2) ◽

pp. 41 ◽

Cited By ~ 3

Author(s):

Macis ◽

Rezvani ◽

Davoli ◽

Cibin ◽

Spataro ◽

...

Keyword(s):

Thin Films ◽

Absorption Spectroscopy ◽

Structural Changes ◽

Structural Evolution ◽

Ex Situ ◽

Edge Structure ◽

X Ray ◽

High Gradients ◽

Different Temperatures ◽

X Ray Absorption

Structural changes of MoO3 thin films deposited on thick copper substrates upon annealing at different temperatures were investigated via ex situ X-Ray Absorption Spectroscopy (XAS). From the analysis of the X-ray Absorption Near-Edge Structure (XANES) pre-edge and Extended X-ray Absorption Fine Structure (EXAFS), we show the dynamics of the structural order and of the valence state. As-deposited films were mainly disordered, and ordering phenomena did not occur for annealing temperatures up to 300 °C. At ~350 °C, a dominant α-MoO3 crystalline phase started to emerge, and XAS spectra ruled out the formation of a molybdenum dioxide phase. A further increase of the annealing temperature to ~500 °C resulted in a complex phase transformation with a concurrent reduction of Mo6+ ions to Mo4+. These original results suggest the possibility of using MoO3 as a hard, protective, transparent, and conductive material in different technologies, such as accelerating copper-based devices, to reduce damage at high gradients.

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Growth and Properties of Lattice Matched GaAsSbN Epilayer on GaAs for Solar Cell Applications

MRS Proceedings ◽

10.1557/proc-0891-ee10-36 ◽

2005 ◽

Vol 891 ◽

Cited By ~ 6

Author(s):

Sudhakar Bharatan ◽

Shanthi Iyer ◽

Kevin Matney ◽

Ward J. Collis ◽

Kalyan Nunna ◽

...

Keyword(s):

Low Temperature ◽

Structural Changes ◽

Ex Situ ◽

Rf Plasma ◽

X Ray Diffraction ◽

X Ray ◽

Peak Energy ◽

Localized Excitons ◽

Matched Layers ◽

Lattice Matched

ABSTRACTIn this work, the growth and characterization of GaAsSbN epilayers nearly lattice matched to GaAs, grown in an elemental solid source molecular beam epitaxy (MBE) system with a RF plasma nitrogen source, are discussed. The Sb and N compositions of the nearly lattice matched layers are 2.6% and 6.8%, respectively, as determined by high resolution x-ray diffraction (HRXRD) and secondary ion mass spectroscopy (SIMS) analysis. The layers are found to be fully strained as evidenced by the presence of Pendellosung fringes on the x-ray diffraction spectra.Effects of in-situ and ex-situ annealing on the low temperature photoluminescence (PL) characteristics are discussed. The 10 K PL peak energy of 1 eV with a FWHM of 18 meV has been achieved on ex-situ annealed samples in N ambient. The temperature dependence of PL peak energy exhibits “S-shaped” behavior in the low temperature regime, indicative of the presence of localized excitons. Raman spectroscopy analysis has been carried out to determine the local structural changes on annealing.

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