Structure and Electrochemical Performances of the Li1+x(Ni0.425Mn0.425Co0.15)1−xO2 Materials

2004 ◽  
Vol 835 ◽  
Author(s):  
N. Tran ◽  
L. Croguennec ◽  
F. Weill ◽  
C. Jordy ◽  
P. Biensan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Reversible Capacity ◽  
Charge Compensation ◽  
Point Of View ◽  
Electrochemical Performances ◽  
Metal Oxidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Transition ◽  
Metal Layers

ABSTRACTLayered Li1+x(Ni0.425Mn0.425Co0.15)1−xO2 materials (x = 0 and 0.12) have been prepared by a coprecipitation method. The substitution of × Li+ ions for × metal ions in the transition metal layers leads to an increase in the average transition metal oxidation state for charge compensation, which was found to be due to the oxidation of Ni2+ ions into Ni3+ ions. The refinement in the R-3m space group of the X-ray diffraction data has shown an increasing lamellar character for the structure of these materials, with increasing overlithiation. Electron diffraction has revealed the presence of a √3.ahex. × √3.ahex. superstructure due to a cationic ordering in the transition metal layers, those being packed with faults along the chex.-axis. From an electrochemical point of view, the reversible capacity in the 2–4.3V decreased with overlithiation, in agreement with a decreasing amount of exchangeable electrons.

Preparation and Electrochemical Properties of Nano Si-C Composite

2016 ◽  
Vol 852 ◽  
pp. 278-282
Author(s):  
Xiao Chen ◽  
Yun Yang ◽  
Shui Jin Yang ◽  
Chuan Qi Feng ◽  
Zai Ping Guo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Current Density ◽  
Reversible Capacity ◽  
Testing System ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initial Capacity ◽  
Scanning Electron

nanoSi-C composite was prepared using eletronspinning technique. The microstructure and morphology of the Si-C composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performances of the Si-C composite were tested by battery testing system. The results showed that the Si-C composite not only behaved high initial capacity but also good cycle performances. The reversible discharge capacity could remain at 860 mAhg-1 when current density was 50 mAg-1. The rate reversible capacity is much higher than that of pure nanoSi anode at same condition.

Preparation and Electrochemical Performances of Li4Ti5O12 as Anode Material

2012 ◽  
Vol 512-515 ◽  
pp. 1976-1979 ◽  
Author(s):  
Fang Gu
Keyword(s):  
Solution Method ◽  
Reversible Capacity ◽  
Electrochemical Performances ◽  
Rate Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Initial Charge ◽  
Charge Discharge ◽  
Scanning Electron

Spinel Li4Ti5O12 was prepared by a solution method. The structure and morphology of the samples were characterized by X-ray diffraction, scanning electron microscopy. The electrochemical performance was investigated by initial charge-discharge at different rate. The results revealed that the crystallinity of Li4Ti5O12 was well, the Li4Ti5O12 prepared by solution method had a relatively smaller particle size and homogeneous morphology. It delivered a discharge capacity 178.59 mAh•g−1 for the Li4Ti5O12 at the 0.2C discharge to 1V. The reversible capacity 141.98mAh•g−1 could be achieved at the 5C . Li4Ti5O12 prepared by a solution method showed good rate performance.

Fe Content Effects on Electrochemical Properties of 0.3Li2MnO3•0.7LiMnxNixFe(1-2x)/2 O2 Cathode Materials

2011 ◽  
Vol 347-353 ◽  
pp. 3518-3521
Author(s):  
Dong Li ◽  
Fang Lian ◽  
Wei Hua Qiu ◽  
Fu Shen Li ◽  
Kuo Chih Chou
Keyword(s):  
Electrochemical Properties ◽  
Cathode Materials ◽  
Reversible Capacity ◽  
Solid State Reaction Method ◽  
Electrochemical Performances ◽  
Fe Doping ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Fe Content

The cathode materials 0.3Li2MnO3•0.7LiMnxNixFe(1-2x)/2O2(0.35≤x≤0.5) were synthesized via low-heating solid-state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TG) and differential thermal analysis (DTA), and their electrochemical performances were also investigated here. The FESEM images of samples revealed that the particle of Fe-substituted samples became smaller and size distribution got narrower compared with the materials without Fe-doping. The results showed that electrochemical properties of the material depended on the content of Fe. 0.3Li2MnO3• 0.7LiMn0.4 Ni0.4Fe2O2 maintained 99.5% of the reversible capacity after 60 cycles

Infrared spectroscopic study of the YPO4-YCrO4 system

1985 ◽  
Vol 50 (10) ◽  
pp. 2139-2145
Author(s):  
Alexander Muck ◽  
Eva Šantavá ◽  
Bohumil Hájek
Keyword(s):  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Point Of View ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Infrared Spectroscopic Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectroscopic ◽  
Diffraction Patterns

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

scholarly journals ZnOTe Compounds Grown by DC-Magnetron Co-Sputtering

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 570
Author(s):  
Olga Sánchez ◽  
Manuel Hernández-Vélez
Keyword(s):  
Molar Fraction ◽  
Variable Parameter ◽  
Point Of View ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sample Series ◽  
Solid Phases ◽  
The One ◽  
High Bulk ◽  
Substrate Sample

ZnOTe compounds were grown by DC magnetron cosputtering from pure Tellurium (Te) and Zinc (Zn) cathodes in O2/Ar atmosphere. The applied power on the Zn target was constant equal to 100 W, while the one applied on the Te target took two values, i.e., 5 W and 10 W. Thus, two sample series were obtained in which the variable parameter was the distance from the Te targets to the substrate. Sample compositions were determined by Rutherford Backscattering Spectroscopy (RBS) experiments. Structural analysis was done using X-Ray diffraction (XRD) spectrometry and the growth of the hexagonal w-ZnO phase was identified in the XRD spectra. RBS results showed high bulk homogeneity of the samples forming ZnOTe alloys, with variable Te molar fraction (MF) ranging from 0.48–0.6% and from 1.9–3.1% for the sample series obtained at 5 W and 10 W, respectively. The results reflect great differences between the two sample series, particularly from the structural and optical point of view. These experiments point to the possibility of Te doping ZnO with the permanence of intrinsic defects, as well as the possibility of the formation of other Te solid phases when its content increases. The results and appreciable variations in the band gap transitions were detected from Photoluminescence (PL) measurements.

Synthesis and characterisation of transition metal substituted barium hollandite ceramics

2006 ◽  
Vol 932 ◽  
Author(s):  
Neil C. Hyatt ◽  
Martin C. Stennett ◽  
Steven G. Fiddy ◽  
Jayne S. Wellings ◽  
Sian S. Dutton ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Powder Diffraction ◽  
Single Phase ◽  
Maximum Density ◽  
Processing Conditions ◽  
Metal Oxidation ◽  
Exafs Data ◽  
X Ray ◽  
Oxygen Atoms

ABSTRACTA range of transition metal bearing hollandite phases, formulated Ba1.2B1.2Ti6.8O16 (B2+ = Mg, Co, Ni, Zn, Mn) and Ba1.2B2.4Ti5.6O16 (B3+ = Al, Cr, Fe) were prepared using an alkoxide - nitrate route. X-ray powder diffraction demonstrated the synthesis of single phase materials for all compositions except B = Mn. The processing conditions required to produce > 95 % dense ceramics were determined for all compositions, except B = Mg for which the maximum density obtained was > 93 %. Analysis of transition metal K-edge XANES data confirmed the presence of the targeted transition metal oxidation state for all compositions except B = Mn, where the overall oxidation state was found to be Mn3+. The K-edge EXAFS data of Ba1.2B1.2Ti6.8O16 (B = Ni and Co) were successfully analysed using a crystallographic model of the hollandite structure, with six oxygen atoms present in the first co-ordination shell at a distance of ca. 2.02Å. Analysis of Fe K-edge EXAFS data of Ba1.2B2.4Ti5.4O16 revealed a reduced co-ordination shell of five oxygens at ca. 1.99Å.

Synthesis and Electrochemical Properties of a LiNi0.7Co0.3O1.9Cl0.1 Cathode Material for Lithium-Ion Battery

2007 ◽  
Vol 336-338 ◽  
pp. 463-465 ◽  
Author(s):  
Xin Lu Li ◽  
Fei Yu Kang ◽  
Yong Ping Zheng ◽  
Xiu Juan Shi ◽  
Wan Ci Shen
Keyword(s):  
Hexagonal Lattice ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Constant Current ◽  
Cyclic Voltammograms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Constant Current Charge ◽  
Initial Cycle ◽  
Partial Oxygen

Partial oxygen in LiNi0.7Co0.3O2 was replaced by chlorine to form LiNi0.7Co0.3O1.9Cl0.1. Phase structure of LiNi0.7Co0.3O1.9Cl0.1 was identified as a pure hexagonal lattice of α-NaFeO2 type by X-ray diffraction. Discharge capacity of LiNi0.7Co0.3O1.9Cl0.1 was 202 mAh/g in initial cycle at 15 mA/g current density in 2.5- 4.3 V potential window. The constant current charge/discharge experiments and cyclic voltammograms showed that chlorine addition was effective to improve reversible capacity and cycle stability of LiNi0.7Co0.3O2.

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