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1.
The low temperature 7Li linewidths and second moments have been analyzed for Li0.33 TiS2 and Li0.97 TiS2. Moment calculations demonstrate that the linewidth is a sensitive indicator of order on a two dimensional lattice of dipoles. The calculated dipolar second moment is not consistent with a simple √3 ao superlattice in Li0.33 TiS2, but is consistent with a random arrangement of lithium ions and several more complex superlattices recently proposed by Kanamori and Kaburagi. 相似文献
2.
W.K. Unger J.M. Reyes O. Singh A.E. Curzon J.C. Irwin R.F. Frindt 《Solid State Communications》1978,28(1):109-112
Ag-intercalated TiS2 has been investigated using electron diffraction and Raman scattering. The energies of the Eg-1 and A1g modes in 1T-TiS2 at 300 K were found to be 232 and 336 cm-1, respectively. In Ag0.3TiS2, at an ambient temperature of 4.2 K, modes were observed at 207, 239, 277, 311, and 347 cm-1. Three of these modes have been associated with the formation of a superlattice at low temperatures. The superlattice formation was observed by electron diffraction and is attributed to an ordering of the silver atoms at interlayer interstices. 相似文献
3.
John A. Wilson 《Solid State Communications》1977,22(9):551-553
Recent data on TiS2 are discussed in terms of the dirty semiconductor model rather than the semimetallic model. The “T2” resistivity is attributed to scattering by “Fivaz-mode”, optic homopolar phonons rather than to electron-hole scattering.A slight semimetallic p-d overlap is finally obtained by TiSe2 and leads to phenomena of the type expected for the ‘excitonic insulator’. 相似文献
4.
The results of ac and dc conductivity measurements on Li2ZrO3, Li4ZrO4, and LiScO2 show that these phases are Li ion conductors. Even though the Li ion conductivity in these phases is quite low, 3.3×10?5, 3.0×10?4, and 4.2×10?7 S m?1 at 573 K, respectively, they are of special interest since they are among the small group of ternary oxides which may be thermodynamically stable against Li. Mechanisms are proposed for the decomposition of these phases at the anode due to Li loss during dc polarization. In addition the electrical conductivity of ternary oxide phases which are, or may be, thermodynamically stable against Li are summarized. 相似文献
5.
The lithium insertion characteristics of lithium vanadate, Li4V3O8, were investigated using LiV3O8 prepared by the precipitation technique as the starting material. The Li4V3O8 phase was formed by lithiation over x=1.5 in Li1+xV3O8, and the diffusion of lithium in this phase determined the reaction rate of insertion more than x=1.5. Improvement of insertion kinetics in the Li4V3O8 phase extended the lithium insertion limit from x=3.2 to x=4.0, compared with the case of LiV3O8 by conventional high temperature synthesis. Lithium insertion proceeds as the single-phase reaction in the range of 3.2<x<4.0. 相似文献
6.
Single phase of Li3AlN2 was prepared from the mixture of Li3N/AlN = 1.2 to 1.5 in molar ratio at 700°C and at 900°C. It crystalizes in the cubic system derived from antifluorite-type structure having the lattice parameter . It is a pure ionic conductor having conductivity of 5 × 10?8ω?1cm?1 at room temperature and an activation energy of 52 kJ/ mol. Its decomposition voltage was 0.85 V at 104°C. The TiS2/Li3AlN2/Li cell could be discharged at a constant current of 45 μA/cm2 at 104°C. 相似文献
7.
Transition metal dichalcogenides have a laminar structure, weakly bound through van der Waals interactions. Due to their technological applications in catalytic processes the bulk structure of many of them has been widely studied in the last 30 years. Some of them, such as NbTe2 and TiSe2, show superconductivity and have been, therefore, the subject of intense study. Novoselov et al. (2005 [1]) achieved to isolate not only graphene but also other bidimensional crystals, among them layers of some dichalcogenides. These bidimensional crystals preserve their monocrystallinity under normal ambient conditions, keeping the crystal structure of the bulk. In this contribution we calculate the magnetic and electronic properties of 2D layers of NbS2 (non-magnetic metal in 3D) and TiS2 (non-magnetic semimetal in 3D) as well as quasi 1D chains cut out from these layers. 相似文献
8.
Results of measurements of conductivity and Hall coefficient in the temperature range 15–300K and of thermal emf in the temperature range 80–400K, carried out on TiS3 samples, are reported. The results indicate that these crystals are semiconducting with extrinsic n-type conductivity. The mobility of the carriers is about 30 cm2/V sec at room temperature, increases up to about 100 cm2/V sec at 100K and drops at lower temperatures. The Seebeck coefficient is in qualitative agreement with these findings but its detailed temperature dependence is not yet understood. 相似文献
9.
Jun Wang Shu Yin Tsugio Sato Fumio Saito 《Journal of Physics and Chemistry of Solids》2007,68(2):189-192
Doping sulphur into titania has been tried using TiS2 as a doper based on the mechanically induced solid-state reaction between TiO2 and TiS2. The prepared samples have been characterized by X-ray diffraction (XRD), Raman spectroscopy and UV-Vis reflectance spectroscopy. Raman analysis, particularly has been proved to be effective in assessing the sulphur doping by correlating the oxygen deficiency of the doped oxide with the change of active Eg mode of rutile phase. 相似文献
10.
11.
M. Mori K. Ohshima S.C. Moss R.F. Frindt M. Plischke J.C. Irwin 《Solid State Communications》1982,43(10):781-784
X-ray measurements have been performed on disordered Stage II Agχ TiS2 crystals with χ = 0.18 and 0.19. The c-axis structure was determined using the 00.l reflections for 4 ?l? 29. A principal result is that the intercalation of Ag+ between S layers produces unequal TiS distances in the adjacent TiS2. The charge transfer to the Ti layer produces an expanded TiS distance adjacent to the Ag layer. The TiS distance away from the Ag ions is accordingly contracted. This effective (indirect) repulsive interaction between Ag+ and Ti may provide a mechanism for staging in these materials by keeping the Ag layers as far apart as possible. 相似文献
12.
Long-time chronoamperometry of TiS2 electrodes immersed in saturated LiClO4/DMF solution was employed to investigate the charge transport processes which govern the rate of Li+ intercalation in TiS2. The intercalation rate and hence, the current, appears to be controlled by the rate of Li+ diffusion within the TiS2. A model has been developed which predicts the current-time behavior under the control of Li+ solid state diffusion. The close agreement of this model with the experimental data allows the solid state diffusion coefficient and other transport parameters (such as effective electrode area) to be evaluated from the measured average grain boundary distance. Typical TiS2 grain boundary distances in the 3–10 μm range yield a geometric mean value of 1.3 × 10?9 cm2/s for the solid state diffusion coefficient; this is in close agreement with previously reported diffusivities as measured by NMR spin-lattice relaxation techniques. 相似文献
13.
NMR measurements of proton spin-lattice relaxation times T1 and T1? in the layered intercalation compounds TiS2(NH3)1.0 and TaS2(NH3)x (x = 0.8, 0.9, 1.0) are reported as functions of frequency and temperature (100 K – 300 K). These observations probe the spectral density of magnetic fluctuations due to motions of the intercalated molecules at frequencies accessible to the T1 (4–90 MHz) and T1? (1–100 kHz) measurements. Since the average molecular hopping time (τ) can be changed by varying temperature, different regions of the spectral density can be examined. For T > 200 K, both T?11 and T?11? vary logarithmically with frequency, reflecting the two dimensional character of the molecular diffusion. The temperature dependence of T1 suggests that a more accurate picture of the short time dynamics is required. No dependence of relaxation rate on vacancy concentration is found. 相似文献
14.
First principles calculations, by means of the full-potential linearized augmented plane wave method within the local density approximation, were carried out for the electronic properties of Li3GaN2. The calculated lattice parameter is in good agreement with the measured one. The bandgap is direct at the Brillouin zone centre. The Li-N and Ga-N bonds are both ionic with a small covalent character of the latter one. 相似文献
15.
本文用X射线粉末法测定了Li2K(IO3)3与Li2NH4(IO3)3的晶体结构和原子参数。发现Li3K(IO3)3,Li2NH4(IO3)3与Li2Rb(IO3)3同晶型,属单斜晶系,空间群为P21/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。
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16.
A. Levasseur M. Kbala J.C. Brethous J.M. Réau P. Hagenmuller M. Couzi 《Solid State Communications》1979,32(10):839-844
New vitreous electrolytes with fast lithium ion carriers have been obtained in the B2O3 - Li2O - Li2SO4 system. The variation of the ionic conductivity is discussed. Raman spectroscopy indicates that sulfate ions are diluted in the vitreous matrix without detectable interaction with the surrounding. 相似文献
17.
《Surface science》1999,430(1-3):199-205
The intercalation of TiS2 single crystals with Cs was studied by transmission electron microscopy. Evidence was found for an intercalation induced 1T→3R structure transformation. The Cs+ ions formed an
structure. In the thinnest parts of the crystals, the intercalation induced cracks and moiré fringes. In thicker parts the 1T→3R transformation was frustrated, with formation of intercalation ribbons and dislocation loops. Air exposure resulted in de-intercalation and oxidation of Cs. The results emphasise the connections between defects and intercalation. 相似文献
18.
Diffusion in the four high-temperature sulphate phases Li2SO4, LiNaSO4, LiAgSO4 and Li4Zn(SO4)3 was studied extensively some 20–30 years ago. We have now carried out a re-evaluation where we include information obtained from a number of studies of other properties. The data are adjusted slightly due to the use of another type of regression analysis. It is characteristic of the four phases that they are both plastic crystals and solid electrolytes (superionic conductors). The cause of the high conductivity is that the mobility of the cations is strongly enhanced by the rotational motion of the translationally static sulphate ions. This is observed not only for the abundant cations, but also for other cations present (mono- as well as polyvalent) and for monovalent anions. Furthermore, both bulk diffusion and transfer along high diffusivity paths are affected. In addition, one can distinguish between different contributions to the bulk diffusion. The ionic radius is a very important parameter, since it determines the solid solubility and the distribution of the ions between the sites that are available in the lattice. All this affects the relative importance of several competing diffusion mechanisms. This gives a qualitative explanation of an anomalous correlation which has been observed in FCC Li2SO4 for monovalent ions (cations as well as anions), namely that both the diffusion coefficients D, and the activation energies Q, decrease when the radius is increased. This holds for hard-core cations (Li, Na, K, Rb), polarizable cations (Ag, Tl) and anions (F, Cl, Br). On the other hand, the situation is normal for divalent cations for which an increase in D corresponds to a decrease in Q. This is the case for hard-core ions (Mg, Ca) as well as for polarizable ones (Zn, Cd, Pb). Migration of the large ions Cs+ and SO2−4 appears to be specially sensitive to how the experiment is prepared. Diffusion in BCC LiNaSO4 and LiAgSO4 has been studied for the two main cations as well as for some dopant ions. A general conclusion is that studies of diffusion of several ions in the same structure can give information that cannot be obtained by other types of experiments. 相似文献
19.
Yanjie ZhangRuiqing Chu Zhijun XuQian Chen Yong LiuGuangchao Zhang 《Current Applied Physics》2012,12(1):204-209
(Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics doped with Li2CO3 and Bi2O3 as sintering aids were manufactured, and their micro structural, dielectric and piezoelectric properties were investigated. All specimens could be well sintered at a low-temperature of 1080 °C. The bulk density of the specimens doped with a small amount of Li2CO3 was enhanced. The dielectric and piezoelectric properties of ceramics were investigated with different amounts of Li2CO3 substitutions. High electrical properties of d33 = 167 pC/N, kp = 0.34, Pr = 40 μC/cm2 and Ec = 38 kV/cm were obtained from the specimen containing 0.1 mol% of Li2CO3 sintered at 1080 °C. 相似文献
20.
Keiichi MinamiAkitoshi Hayashi Satoshi UjiieMasahiro Tatsumisago 《Solid State Ionics》2011,192(1):122-125
Electrical and electrochemical properties of the 70Li2S·(30 − x)P2S5·xP2S3 and the 70Li2S·(30 − x)P2S5·xP2O5 (mol%) glass-ceramics prepared by the mechanical milling technique were investigated. Glass-ceramics with 1 mol% P2S3 and 3 mol% P2O5 showed the highest conductivity of 5.4 × 10− 3 S cm− 1 and 4.6 × 10− 3 S cm− 1, respectively. Moreover, these glass-ceramics showed higher electrochemical stability than the 70Li2S·30P2S5 (mol%) glass-ceramic. From the XRD patterns of the obtained glass-ceramics, trivalent phosphorus and oxygen were incorporated into the Li7P3S11 crystal. We therefore presume that the Li7P3S11 analogous crystals, which were formed by incorporating trivalent phosphorus and oxygen into the Li7P3S11 crystal, improve the electrical and electrochemical properties of the glass-ceramics. An all-solid-state cell using the 70Li2S·29P2S5·1P2S3 (mol%) glass-ceramic as solid electrolyte operated under the high current density of 12.7 mA cm− 2 at the high temperature of 100 °C. The cell showed an excellent cyclability of over 700 cycles without capacity loss. 相似文献