7789-24-4Relevant articles and documents
Loesch, H. J.,Stenzel, E.,Wuestenbecker, B.
, p. 3841 - 3842 (1991)
Stability of Li2CO3 in cathode of lithium ion battery and its influence on electrochemical performance
Bi, Yujing,Wang, Tao,Liu, Meng,Du, Rui,Yang, Wenchao,Liu, Zixuan,Peng, Zhe,Liu, Yang,Wang, Deyu,Sun, Xueliang
, p. 19233 - 19237 (2016)
Lithium carbonate is an unavoidable impurity at the cathode side. It can react with LiPF6-based electrolyte and LiPF6 powder to produce LiF and CO2, although it presents excellent electrochemical inertness. Samples of Li2CO3-coated and LiF-coated LiNi0.8Co0.1Mn0.1O2 were prepared to compare their influence on a cathode's behavior. After 200 cycles at 1C, in contrast to 37.1% of capacity retention for the Li2CO3-coated material, the LiF-coated LiNi0.8Co0.1Mn0.1O2 retained 91.9% of its initial capacity, which is similar to the fresh sample. This demonstrates that decomposition of Li2CO3 can seriously deteriorate cyclic stability if this occurs during working.
Cohen et al.
, p. P37 (1968)
YHO, an Air-Stable Ionic Hydride
Zapp, Nicolas,Auer, Henry,Kohlmann, Holger
, p. 14635 - 14641 (2019)
Metal hydride oxides are an emerging field in solid-state research. While some lanthanide hydride oxides (LnHO) were known, YHO has only been found in thin films so far. Yttrium hydride oxide, YHO, can be synthesized as bulk samples by a reaction of Y2O3 with hydrides (YH3, CaH2), by a reaction of YH3 with CaO, or by a metathesis of YOF with LiH or NaH. X-ray and neutron powder diffraction reveal an anti-LiMgN type structure for YHO (Pnma, a = 7.5367(3) ?, b = 3.7578(2) ?, and c = 5.3249(3) ?) and YDO (Pnma, a = 7.5309(3) ?, b = 3.75349(13) ?, and c = 5.3192(2) ?); in other words, a distorted fluorite type with ordered hydride and oxide anions was observed. Bond lengths (average 2.267 ? (Y-O), 2.352 ? (Y-H), 2.363 ? (Y-D), >2.4 ? (H-H and D-D), >2.6 ? (H-O and D-O), and >2.8 ? (O-O)) and quantum-mechanical calculations on density functional theory level (band gap 2.8 eV) suggest yttrium hydride oxide to be a semiconductor and to have considerable ionic bonding character. Nonetheless, YHO exhibits a surprising stability in air. An in situ X-ray diffraction experiment shows that decomposition of YHO to Y2O3 starts at only above 500 K and is still not complete after 14 h of heating to a final temperature of 1000 K. YHO hydrolyzes in water very slowly. The inertness of YHO in air is very beneficial for its potential use as a functional material.
Ruedorff, W.,Kaendler, J.
, p. 418 - 418 (1957)
PREPARATION OF HIGHLY PURE LITHIUM AND SODIUM FLUORIDES USING SOLVENT EXTRACTION.
Kobayashi
, p. 2965 - 2966 (1988)
LiF and NaF can be purified by solvent extraction. The impurity concentrations in the purified NaF are 2. 5 ng g** minus **1 for chromium, 60 ng g** minus **1 for iron, 0. 03 ng g** minus **1 for cobalt, and 1. 5 ng g** minus **1 for copper. The concentra
Flux crystal growth, structure, magnetic and optical properties of a family of alkali uranium(IV) phosphates
Usman, Mohammad,Morrison, Gregory,Klepov, Vladislav V.,Smith, Mark D.,zur Loye, Hans-Conrad
, p. 19 - 26 (2019)
A family of alkali uranium(IV) phosphates, AU2(PO4)3 (A = Li – Cs), was synthesized as single crystals by the reaction of US2 and (NH4)2HPO4 in the respective ACl (A = Li – Cs) flux contained in a sealed fused-silica tube at 850 °C, and as phase pure powders from a similar reaction using UF4 as the uranium source. AU2(PO4)3 (A = Li – Rb) crystallize in the NaTh2(PO4)3 (NTP) structure type with monoclinic space group C2/c and consist of a 3D structure that features a framework composed of edge- and corner-sharing polyhedra. The cesium analogue, CsU2(PO4)3, crystallizes in a different structure with space group P21/n that is related to the NaZr2(PO4)3 (NZP) structure type and consists of a framework composed of corner-sharing polyhedra. Two new alkali uranium phosphates, Li2U(PO4)2 and Cs4U4(P2O7)5, were also grown as single crystals at 700 °C. Li2U(PO4)2 was isolated in approximately 30% yield based on uranium. Li2U(PO4)2 crystallizes in space group P21/c exhibiting a layered structure while Cs4U4(P2O7)5, crystallizes in space group P21/n in a new structure type featuring a 3D framework. The magnetic susceptibilities and the field dependent magnetizations were measured for AU2(PO4)3 (A = Li, Na, K and Cs); all compounds exhibited negative Weiss temperatures with no obvious antiferromagnetic transition. Optical properties were measured by UV–vis and IR spectroscopy.
Arisawa, Takashi,Suzuki, Yoji,Maruyama, Yoichiro,Shiba, Koreyuki
, p. 473 - 480 (1983)
Thermal decomposition of lithium-inserted NbO2F
Permer,Lundberg
, p. 145 - 159 (1989)
The thermal decomposition of lithium-inserted NbO2F was studied by differential scanning calorimetry. Samples of LixNbO2F (O ≤ x ≤ 1.8) were heated to 800 and 950 K. The thermograms revealed that decomposition started within the temperature range 640 - 780 K, followed by a second step at approximately 900 K. The products were characterized by X-ray powder diffraction and electron diffraction patterns and by high-resolution electron microscopy. The following phases were obtained at 800 K: LiF, NbO2F, the low pressure form of Nb3O7F, and lithium-enriched forms of P-Nb2O5, NbO2 and LiNbO3. At 950 K, NbO2F disappeared, and LiNb3O8 and the high pressure form of Nb3O7F coexisted with the other phases obtained at 800 K. The formation of structures built up of approximately hexagonally close-packed anion arrangements is discussed.
Patil, R. R.,Mohari, S. V.
, (1995)
HF-Free Synthesis of Li2SiF6:Mn4+: A Red-Emitting Phosphor
Stoll, Christiane,Bandemehr, Jascha,Kraus, Florian,Seibald, Markus,Baumann, Dominik,Schmidberger, Michael J.,Huppertz, Hubert
, p. 5518 - 5523 (2019/03/29)
Li2SiF6:Mn4+ was synthesized via a new HF-free synthesis route by a high-pressure/higherature doping experiment at 5.5 GPa and 750 °C. It is proven that the phosphor cannot be synthesized by the common wet-chemical precipitation route in aqueous HF. The sample was characterized by powder X-ray diffraction, EDX, and luminescence spectroscopy. At room temperature, Li2SiF6:Mn4+ exhibits seven emission lines with the strongest line at max 630 nm and a dominant wavelength of dom 618 nm. The CIE coordinates are 0.688 and 0.312 for x and y, respectively. The compound shows a luminous efficacy of radiation (LER) of 218 lm Wopt-1, which exceeds the LER of current state-of-the-art red LED phosphor K2SiF6:Mn4+ by 7% due to a blue-shift of the emission. It reveals excellent thermal quenching behavior up to 125 °C.