- Synthesis, structures and properties of the new lithium cobalt(II) phosphate Li4Co(PO4)2
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α-Li4Co(PO4)2 has been synthesized and crystallized by solid-state reactions. The new phosphate crystallizes in the monoclinic system (P21/a, Z=4, a=8.117(3) A, b=10.303(8) A, c=8.118(8) A, β=104.36(8) A) and is isotypic to α-Li4Zn(PO4)2. The structure of α-Li4Co(PO4)2 has been determined from single-crystal X-ray diffraction data {R1=0.040, wR 2=0.135, 2278 unique reflections with Fo>4σ (Fo)}. The crystal structure, which might be regarded as a superstructure of the wurtzite structure type, is build of layers of regular CoO4, PO4 and Li1O4 tetrahedra. Lithium atoms Li2, Li3 and Li4 are located between these layers. Thermal investigations by in-situ XRPD, DTA/TG and quenching experiments suggest decomposition followed by formation and phase transformation of Li4Co(PO4) 2:α-Li4Co(PO4)2442°C β-Li3PO4LiCoPO4 ?773°C β-Li4Co(PO4)2quenchingto25°C α-Li4Co(PO4)2 According to HT-XRPD at θ=850°C β-Li4Co(PO4)2 (Pnma, Z=2, 10.3341(8) A, b=6.5829(5) A, c=5.0428(3) A) is isostructural to γ-Li3PO4. The powder reflectance spectrum of α-Li4Co(PO4)2 shows the typical absorption bands for the tetrahedral chromophore [CoIIO 4].
- Glaum,Gerber,Schulz-Dobrick,Herklotz,Scheiba,Ehrenberg
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- Synthesis, crystal structure and properties of Li2Cu 5(PO4)4
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Li2CuII5(PO4)4 has been obtained by various reactions starting from copper or Cu2O. Crystallization was achieved using I2 as oxidant and mineralizer. The new orthophosphate crystallizes in space group P1, Z = 2, with a = 6.0502(3) A, b = 9.2359(4) A, c = 11.4317(5) A, α = 75.584(2)°, β = 80.260(2)°, γ = 74.178(2)°, at 293 K. Its structure has been determined from X-ray single-crystal data and refined to R1 = 0.022{wR2 = 0.058 for 4633 unique reflections with Fo > 4σ (Fo)}. From magnetic measurements μeff = 1.51 μB/Cu and θP = -37.4 K have been determined. The Vis/NIR spectrum of aqua-green Li2Cu 5(PO4)4 shows a single broad band centered around 1 = 12000 cm-1. Magnetic behavior and spectrum are discussed within the angular overlap model. Copyright
- Snyder,Glaum, Robert
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- Lithium zincopyrophosphate, Li2Zn3(P 2O7)2
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The title compound, dilithium(I) trizinc(II) bis-[diphos-phate(4-)], is the first quaternary lithium zincopyro-phosphate in the Li-Zn-P-O system. It features zigzag chains running along c, which are built up from edge-sharing [ZnO5] trigonal bipyramids. O
- Ji, Lina,Ma, Hongwei,Liang, Jingkui
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- Thermodynamic aspects of the reaction of lithium with SnP2O 7 based positive electrodes
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The reaction of lithium with tin pyrophosphate, 4 Li+ +Sn P2 O7 → Li4 P2 O7 +Sn, which yields a nanocomposite formed by tin and lithium pyrophosphate, has been probed electrochemically by step potential electrochemical spectroscopy. The thermodynamic characteristics (i.e., ΔG, ΔH and ΔS) of the formation of nanosized tin particles have been determined from data obtained under equilibrium conditions at different temperatures. A first order change in free energy clearly reflects the transformation of α tin to Β tin at 286±1 K. This shows that for the electrochemically produced nanocrystalline tin phase, the transition is at the same temperature as that expected for bulk materials. Interestingly this transition is not significantly limited by kinetics in the way that bulk tin metal is infamous for in tin plague and so we have been able to derive values for these important thermodynamic parameters. Taking into account the absence of long range order in the nanocomposites, the observations indicate that performance of batteries based upon tin oxides as the anode precursor may be affected by small changes of temperature around the transition point. The thermodynamics for this displacive reaction are found to be of a similar order to those obtained for a typical intercalation reaction. However, it seems that the entropy contribution to the free energy dominates for the displacive reaction, which is likely due to the formation of nanosized tin particles.
- Attidekou, Pierrot S.,Garcia-Alvarado,Connor, Paul A.,Irvine, John T. S.
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- Phase relations of Li2O-MnO-P2O5 system and the electrochemical properties of Li1+xMn1-xPO4 compounds
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The phase relations of Li2O-MnO-P2O5 ternary system under reducing atmosphere have been systematically investigated by means of X-ray diffraction. Inferior to what we expected, no other new lithium manganese phosphates exist within the Li2O-MnO-P2O5 ternary system under the reducing atmosphere. A high-pressure phase Mn3(PO4)2 with graftonite Fe3(PO4)2-type structure can be easily obtained in the MnO-P2O5 system under the ordinary solid-state reaction conditions in H2/Ar atmosphere and its detail structure is presented. In addition, the solid solubility of Li1+xMn1-xPO4 is determined as -0.05 ≤ x ≤ 0.03. The lattice parameters and electrochemical properties of Li1+xMn1-xPO4 with x content are investigated. The electrochemical test results show that excess Li-ion (x > 0) or the excess Mn-ion (x 4 has an unfavorable effect on the electrochemical properties caused by the deterioration of the lithium diffusion along the one-dimensional tunnels.
- Yan, Danlin,Zhao, Yanming,Dong, Youzhong,Liang, Zhiyong,Lin, Xinghao
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- Structure of vanadium-oxygen and phosphorus-oxygen groups in molten alkali and alkaline-earth vanadates and phosphates: A high-temperature Raman scattering study
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The melting of alkali-metal ortho-, pyro-, and polyvanadates and V 2O5 is investigated by high-temperature Raman scattering spectroscopy. The Raman lines arising from the characteristic vibrational modes of the terminal, middle, and bridging groups of anions with various degrees of condensation of vanadium-oxygen tetrahedra in vanadate melts are identified. The origin of structural similarities and distinctions between the vanadium-oxygen and phosphorus-oxygen complexes in melts is analyzed.
- Voron'ko,Sobol',Shukshin
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- Effect of Water Vapor on the Formation of Lithium cyclo-Hexaphosphate
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The effect of water vapor on the formation of lithium cyclo-hexaphosphate Li6P6O18 (P6m) from trilithium hydrogenpyrophosphate monohydrate Li3HP2O7*H2O was investigated by means of DTA-TG, X-ray diffraction analysis, isothermal heating with electric furnace, and HPLC.Li3HP2O7*H2O lost the water of crystallization at about 180 deg C to give anhydrous Li3HP2O7.At 300 deg C the disproportionation of Li3HP2O7 anhydride to Li4P2O7 and Li4P4O12 (P4m) proceeded faster under humid conditions than under dry air, and subsequently P4m increased with a decrease in P2 and soluble polyphosphates (Ppoly).At 400 deg C, P4m changed largely to P6m under humid conditions.In these reaction processes, water plays an important role as catalyst in the cyclization by dehydration of the end group and in ring opening by attacking the P-O-P bond.At 450 deg C, the amounts of P2 and P6m were almost equal under both humid and dry conditions, because all of P4m thermally changed to P6m.
- Nariai, Hiroyuki,Motooka, Itaru,Tsuhako, Mitsutomo
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- Synthesis and characterization of a new layered lithium zinc phosphate hydrate
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A new layered lithium zinc phosphate hydrate, Li2Zn(HPO4)2· 0.66H2O, isostructural with Na2Zn(HPO4)2·4H2O was prepared by the direct ambient pressure and temperature reaction between zinc 2,4-pentanedionate, phosphoric acid, and lithium hydroxide. The as-prepared sample is monoclinic (a = 8.896(8) A, b = 13.092(5) A, c = 10.882(9) A, and β = 115.760(6)°). The prepared solid undergoes three thermal transformations when it is heated from 110 to 600°C. The first two transformations are due to the release of intercalated water molecules and the third one is due to the HPO42--P2O74- transition.
- Bensalem
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- Nature of insulating-phase transition and degradation of structure and electrochemical reactivity in an olivine-structured material, LiFePO4
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Synthesis time using microwave irradiation was varied to elucidate the electrochemical degradation mechanism of LiFePO4 related to the evolution of Fe2P. When the amount of Fe2P was above a critical level, LiFePO4/su
- Song, Min-Sang,Kang, Yong-Mook,Kim, Yong-Il,Park, Kyu-Sung,Kwon, Hyuk-Sang
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- Melt casting LiFePO4: I. Synthesis and characterization
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A melt casting process to make an electrochemically active LiFeP O 4 cathode material was explored. The melting of carbon-coated LiFeP O4 powder at 1000°C followed by its cooling leads to a high purity LiFeP O4 material wi
- Gauthier,Michot,Ravet,Duchesneau,Dufour,Liang,Wontcheu,Gauthier,MacNeil
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- Phase relation of Li2O-CoO-P2O5 ternary system and electrochemical behaviors of Co-base polyphosphates within this system
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The subsolidus phase relations in the Li2O-CoO-P2O5 system have been systematically investigated by means of X-ray diffraction (XRD) pattern. The results have confirmed 6 binary compounds, 5 ternary compounds and 17 three-
- Lin, Xinghao,Zhao, Yanming,Liang, Zhiyong,Yan, Danlin,Liu, Xudong,Wen, Mingming,Dong, Youzhong,Kuang, Quan
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p. 727 - 733
(2016/01/09)
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- Synthesis, crystal structure and lithium ion conduction of Li 3BP2O8
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Single crystals of Li3BP2O8 were prepared by heating a mixture of starting materials with a Li : B : P molar ratio of 22 : 11 : 13 at 933 K in air and by cooling at a rate of -10 K h-1. The X-ray diffraction (XRD) reflections of a single crystal were indexed with triclinic cell parameters: a = 5.1888(5) A, b = 7.4118(7) A, c = 7.6735(7) A, α = 101.18(1)°, β = 105.07(1)°, γ = 90.34(1)° (space group P1 (no. 2)). In the crystal structure of Li3BP2O8, BO4 and PO4 tetrahedra share O atoms and form one-dimensional 1∞[BP2O 8]3- chains along the c-axis direction. A polycrystalline Li3BP2O8 bulk sample was synthesized by the solid state reaction of Li4P2O7 and LiPO 3 prepared from the starting materials in advance with H 3BO3 at 923 K. The lithium ion conductivities measured for the polycrystalline sample by the AC impedance and DC methods were 1.5 × 10-5 S cm-1 at 583 K and 6.0 × 10-8 S cm-1 at 423 K, respectively.
- Hasegawa, Toru,Yamane, Hisanori
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p. 2294 - 2300
(2014/01/17)
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- Phase relationships in the M2ZnP2O7-M′2ZnP 2O7 sections of the M4P2O7-M′4P2O 7-Zn2P2O7 (M = Li, Na, K) systems
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Phase relationships in the M2ZnP2O7-M′2ZnP 2O7 (M, M′ = Li, Na, K) pseudobinary systems are studied. New chemical compounds NaKZnP2O7, LiNaZnP2O7, and LiKZnP2O7 are obtained. Solid solutions in Na2ZnP2O7, K2ZnP2O7, and NaKZnP2O7 are found to exist in the Na2ZnP2O7-K2ZnP2O 7 system.
- Petrova,Novikova,Mal'shikov,Popova,Grebenshchikov
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p. 212 - 216
(2008/10/08)
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- PREPARATION AND PROPERTIES OF CYCLOPHOSPHATOPHOSPHONATES WITH 6- AND CYCLOPHOSPHATES WITH 6- TO 20-MEMBERED RINGANIONS
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Pure cyclotri-, -hexa-, -octa- and decaphosphates are prepared by topochemical controlled thermal dehydration of certain dihydrogenphosphates.Cyclophosphatophosphonates are prepared by heating geminal diphosphonic acids and phosphoric acid in molten urea.Cyclophosphatanions larger than cyclopentaphosphate are very resistant against hydrolysis.The complexing abilities of cyclophosphates increase with ring size.Phosphatophosphonates are more resistant to ring cleavage than the correspondend cyclophosphates.
- Schuelke, Ulrich
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