Interaction between two double layers for FeCl3 types electrolytes at y0 > yd > 01

Interaction between two double layers for FeCl3 type electrolytes at y ₀ > y _d > 0 were investigated with the aid of λ parameter methods and the accurate numeral results were given. When y _d increases, the interaction energies increase at constant y ₀ and ξ _d . The maximum of the interaction energies between two double layers for $ A_{v_ + } B_{v_ - } $ A_{v_ + } B_{v_ - } type electrolytes at y ₀ > y _d > 0 is independent of y ₀, but increases with the augment of y _d . The interaction energies between two double layers for NaCl, CaCl₂, FeCl₃ and Na₂SO₄ type electrolytes at y ₀ = 5 and y _d = 2 were compared. If the negative or positive ions for {ie39-2} type electrolytes have the same charge number, the maximum of their interaction energies increases with the augment of the charge number of the ions with opposite charge. For a pairs conjugate type electrolytes like CaCl₂ and Na₂SO₄ or FeCl₃ and Na₃PO₄, the larger the charge number of the negative ions is, the larger the maximum of the interaction energies is. The results for FeCl₃ type electrolytes at y ₀ > y _d > 0 can also be applied to Na₃PO₄ type electrolytes at y ₀ < y _d < 0.     

High efficient calculation of the interaction energies between two double layers for CaCl2 type asymmetric electrolytes at y 0 > y d > 0

Several rapidly convergent series for the highly efficient calculation of the interaction energies between dissimilar double layers for CaCl₂ type electrolytes at y ₀ > y _d > 0 were derived. The accurate numeral results were given and several approximate expressions were obtained for y ₀ ≪ 1. The number of the series terms required to obtain the interaction energies with six significant digits is not more than 3 when the dimensionless surface potential of double layers y ₀ ≤ 20. The interaction energies between dissimilar double layers for Na₂SO₄ or CaCl₂ type electrolytes depend significantly on the y _d value, while the interaction energies for Na₂SO₄ type electrolytes is practically independent of y ₀. The present results can also be applied to Na₂SO₄ type electrolytes at y ₀ < y _d < 0. The text was submitted by the authors in English.     

High-efficient calculation of the interaction energies between dissimilar double layers for Na2SO4-type asymmetric electrolytes at y 0 > y d > 0

Several rapidly convergent series for highly efficient calculation of the interaction energies between dissimilar double layers for Na₂SO₄-type electrolytes at y ₀ > y _d > 0 are derived, the accurate numerical results are given, and several approximate expressions are obtained for y ₀ ≪ 1. The number of the series terms required to obtain the interaction energies with six significant digits via the use of the series derived is no more than 2 when the dimensionless surface potential of double layers y ₀ ≤ 20. The interaction energies between dissimilar double layers for NaCl-or Na₂SO₄-type electrolytes are remarkably affected by the value of y _d,, but the interaction energies for Na₂SO₄-type electrolytes are hardly affected by the value of y ₀. The present results can also be applied to CaCl₂-type electrolytes at y ₀ < y _d < 0. The text was submitted by the authors in English.     

Two rapidly convergent series for calculating the interaction energies between two dissimilar double layers for Na2SO4 or CaCl2 types asymmetric electrolytes at y0 > 0 > yd ≥ ?y0

Two rapidly convergent series for calculating the interaction energies between two dissimilar double layers for Na₂SO₄ or CaCl₂ types asymmetric electrolytes at y ₀ > 0 > yd ≥ −y ₀ were derived, the number of the series terms required to obtain the interaction energies with six significant digits is not more than 4 when the dimensionless surface potential of two dissimilar double layers changes from −20 to + 20. The absolute values of the interaction energies V between two dissimilar double layers for Na₂SO₄, CaCl₂ and NaCl types electrolytes obey the following relations: when −y _d = y ₀, V′Na₂SO₄ = V′CaCl₂; when −y _d > y ₀, V′Na₂SO₄ > V′CaCl₂; when −y _d < y ₀, V′Na₂SO₄ < V′CaCl₂; V′Na₂SO₄ or V′CaCl₂ is always less than V′_NaCl. Several approximate expressions were given for interaction energy at y ₀ and −y _d ≪ 1.     

Interaction between two double-layers for FeCl<Subscript>3</Subscript> and Na<Subscript>3</Subscript>PO<Subscript>4</Subscript> type electrolytes in case the signs of potentials on two plates are opposite

The interaction energies between two double layers for FeCl₃ or Na₃PO₄ type electrolytes at y ₀ > 0 >y _d>—y ₀ were calculated with the aid of 7n parameter methods and the accurate numeral results were given when the dimensionless surface potential of two double layers changes from -20 to +20. When ∣y _d∣ > 5, the absolute value of the interaction energies, ∣V’∣, for FeCl₃ type electrolytes at y ₀= 1 stops to increase. When y ₀> 8, the ∣V’∣ for FeCl₃ type electrolytes at y _d= -1 ceases to change. The influence of y _d on ∣V’∣ for FeCl₃ type electrolytes is more significant than the influence of y ₀. The variation of ∣V’∣ with y _d and y ₀ for Na₃PO₄ type electrolytes is opposite to that for FeCl₃ type electrolytes. The interaction energies between two dissimilar double layers for Na₂SO₄, CaCl₂, NaCl, Na₃PO₄ and FeCl₃ type electrolytes at y ₀= 1 and y _d = -10 are compared and the results indicate that the interaction energies close to each other for FeCl₃ and CaCl₂ type electrolytes and for Na₃PO₄ and Na₂SO₄ type electrolytes, respectively. ∣V’∣ increases with the raises of y ₀ or ∣y _d∣, but decreases with the raises of z ₊ or z _-.     

Interactions between two similar plane parallel double layers for Na<Subscript>3</Subscript>PO<Subscript>4</Subscript> type asymmetric electrolytes at positive surface potential

The interactions between two similar plane double-layers for Na₃PO₄ type asymmetric electrolytes are described using hyperelliptic integrals. The mathematical treatments of hyperelliptic integrals are much more difficult than those of elliptic integrals. The system was successfully treated with the aid of the λ parameter method. The interaction energies for the system at positive surface potential are expanded in power series at low, moderate, and high potentials, respectively. The accurate numeral results and V′-ξ _d curves are given for y ₀ ≤ 20 and can be used to check the validity of approximate expressions obtained. When y ₀ ≥ 5, V′ hardly changes with y ₀. The interaction energies between two similar plane parallel double layers for symmetric and asymmetric electrolytes at y ₀ = 1 were compared; when ξ _d → 0, the interaction energies for Na₃PO₄ type electrolytes are much larger than for electrolytes of other types. The present results are also fit for FeCl₃-type asymmetric electrolytes at negative surface potential. The text was submitted by the author in English.     

Interaction between two similar plane parallel double layers for Mg<Subscript>3</Subscript>(PO<Subscript>4</Subscript>)<Subscript>2</Subscript> type asymmetric electrolytes at positive surface potential

The interaction between two similar plane double-layers for Mg₃(PO₄)₂ type asymmetric electrolytes was investigated with the aid of λ parameter method. The interaction energies for the system at positive surface potential were expanded in power series at low and high potential, respectively. The accurate numeral results and V′-ξ _d curves were given for y ₀ ≤ 20 and they can be used to check up the validity of approximate expressions obtained. When y ₀ ≥ 5, V′ hardly changes with y ₀. The interaction energies between two similar plane parallel double layers for symmetric and asymmetric electrolytes at y ₀ = 1 were compared; when ξ _d is small, the interaction energies for Mg₃(PO₄)₂ type electrolytes increase more drastically than for other type electrolytes. The present results are also fit for Al₂(SO₄)₃ type asymmetric electrolytes at negative surface potential. The article is published in the original.     

Interaction between two similar plane parallel double layers for K<Subscript>4</Subscript>Fe(CN)<Subscript>6</Subscript> type asymmetric electrolytes at positive surface potential

The interaction between two similar plane double-layers for K₄Fe(CN)₆ type asymmetric electrolytes was investigated with the aid of λ parameter method. The interaction energies for the system at positive surface potential were expanded in a power series. This formula covers with the bounds of all potential (y ₀ ≤ 20). The accurate numeral results and V′ − ζ _d curves were given for y ₀ ≤ 20. When y ₀ ≥ 2, V′ hardly changes with y ₀. The interaction energies between two similar plane parallel double layers for the different type electrolytes at y ₀ = 1 were compared. The present results are also fit for Th(NO₃)₄ type electrolytes at negative surface potential.     

Interaction between Two Similar Plane Parallel Double Layers for Al2(SO4)3 Type Asymmetric Electrolytes at Positive Surface Potential

The interaction between two similar plane double-layers for Al₂(SO₄)₃ type asymmetric electrolytes was investigated with the aid of λ parameter method. The interaction energies for the system at positive surface potential were expanded in the power series at low and high potential, respectively. The high potential formula can be applied to 0.2 ≤ y_e  < y ₀ ≤ 20. This almost covers with the bounds of all potential, and that the calculative method is relative simple. The accurate numeral results and V′?ξ_d curves were given for y ₀ ≤ 20. When y ₀ ≥ 5, V′ hardly change with y ₀. The interaction energies between two similar plane parallel double layers for the different type electrolytes at y ₀ = 1 were compared. The present results are also fit for Mg₃(PO₄)₂ type electrolytes at negative surface potential.     

Interaction Between Two Similar Plane Parallel Double Layers for (NH4)2Fe(SO4)2 or (NH4)2Cu(SO4)2 Type Complex Salt Electrolytes at Positive Surface Potential

Interaction energies between two similar plane parallel double layers for (NH₄)₂Fe(SO₄)₂ or (NH₄)₂Cu(SO₄)₂ type complex salt electrolytes at positive surface potential were expanded in a power series and accurate numeral results were given for 0.1 ≤ y _e  < y ₀ ≤ 20. The general expressions were given for the interaction energies of A _ν +B _ν′ +C_ν? type complex salt electrolytes at y > 0. The interaction energies for simple salts NaCl, CaCl₂, Na₂SO₄, FeCl₃, Na₃PO₄, Mg₃(PO₄)₂, Al₂(SO₄)₃, and complex salts (NH₄)₂Fe(SO₄)₂ or (NH₄)₂Cu(SO₄)₂ at y ₀ = 1 were compared. There was hardly difference between these simple salts and this complex salt for the interaction energies. The interaction energy for complex salt (NH₄)₂Fe(SO₄)₂ was close to that for simple salt Na₃PO₄.

Supplemental files are available for this article. Go to the publisher's online edition of the Journal of Dispersion Science and Technology to view the free supplemental file.     

水系混合离子全电池LiMn2O4//NaTi2(PO4)3

分别以LiMn_2O_4,NaTi_2(PO_4)_3为正负极,1 mol·L~(-1) Li_2SO_4和0.5 mol·L~(-1) Na_2SO_4的混合水溶液为电解液组装成一种水系混合离子全电池。分别将正负极材料在3种不同水相电解液(1 mol·L~(-1) Li_2SO_4、0.5 mol·L~(-1)Na_2SO_4以及1 mol·L~(-1) Li_2SO_4+0.5 mol·L~(-1)Na_2SO_4混合电解液)中进行循环伏安和恒流充放电测试,结果发现,LiMn_2O_4在上述电解液中仅有Li~+的脱出/嵌入而Na~+由于半径较大而不参与该过程,NaTi_2(PO_4)_3在3种电解液中Li+、Na+均参与嵌入/脱嵌过程,且Li~+和Na~+的嵌入/脱出峰电位相差不大,分别为-0.82和-0.64 V,-0.95和-0.75 V;全电池在265 mA·g~(-1)电流密度下平均放电电压为1.55 V,充放电比容量分别为100.1和74.9 m Ah·g~(-1)。     

Matrix-Inducing Synthesis of SrxY10?x(SiO4)y(PO4)6?yO2: Eu3+ Micron Crystalline Coral Like Phosphors by Sol-Gel Composition of Hybrid Precursors

In the context, Sr_xY_10−x(SiO₄)_y(PO₄)_6−yO₂ doped with 1 mol%Eu³⁺ (x = 2, y = 6; x = 4, y = 4; x = 5, y = 3; x = 8, y = 0) were synthesized by using 3-aminopropyl-triethoxysilane (APES) as the sources of the silicate network. X-ray diagrams confirm that Sr_xY_10−x(SiO₄) _y(PO₄)_6−yO₂: Eu³⁺ solid solutions are formed as a pure apatitic phase. The SEM picture shows that there exist some novel unexpected coral like morphological structures. The luminescent intensity is the strongest for the host composition of Sr₄Y₆(SiO₄)₄(PO₄)₂O₂ although the effect of the composition on the luminescent intensity is little.     

Carbon coated Na3V2(PO4)3 as novel electrode material for sodium ion batteries

A Na₃V₂(PO₄)₃ sample coated uniformly with a layer of 6 nm carbon has been successfully synthesized by a one-step solid state reaction. This material shows two flat voltage plateaus at 3.4 V vs. Na⁺/Na and 1.63 V vs. Na⁺/Na in a nonaqueous sodium cell. When the Na₃V₂(PO₄)₃/C sample is tested as a cathode in a voltage range of 2.7-3.8 V vs. Na⁺/Na, its initial charge and discharge capacities are 98.6 and 93 mAh/g. The capacity retention of 99% can be achieved after 10 cycles. The electrode shows good cycle performance and moderate rate performance. When it is tested as an anode in a voltage range of 1.0-3.0 V vs. Na⁺/Na, the initial reversible capacity is 66.3 mAh/g and the capacity of 59 mAh/g can be maintained after 50 cycles. These preliminary results indicate that Na₃V₂(PO₄)₃/C is a new promising material for sodium ion batteries.     

Nickel(IV) dithiocarbamato complexes of the [Ni(ndtc)3]X type: X-ray structure of [Ni(hmidtc)3][FeCl4]

A series of fourteen octahedral nickel(IV) dithiocarbamato complexes of the general formula [Ni(ndtc)₃]X·yH₂O {ndtc stands for the appropriate dithiocarbamate anion, X stands for ClO₄⁻ (1-8; y = 0) or [FeCl₄]⁻ (9-14; y = 0 for 9-12, 1 for 13 and 0.5 for 14} was prepared by the oxidation of the corresponding nickel(II) complexes, i.e. [Ni(ndtc)₂], with NOClO₄ or FeCl₃. The complexes, involving a high-valent Ni^IVS₆ core, were characterized by elemental analysis (C, H, N, Cl and Ni), UV-Vis and FTIR spectroscopy, thermal analysis and magnetochemical and conductivity measurements. The X-ray structure of [Ni(hmidtc)₃][FeCl₄] (9) was determined {it consists of covalently discrete complex [Ni(hmidtc)₃]⁺ cations and [FeCl₄]⁻ anions} and this revealed slightly distorted octahedral and tetrahedral geometries within the complex cations, and anions, respectively. The Ni(IV) atom is six-coordinated by three bidentate S-donor hexamethyleneiminedithiocarbamate anions (hmidtc), with Ni-S bond lengths ranging from 2.2597(5) to 2.2652(5) Å, while the shortest Ni···Cl and Ni···Fe distances equal 4.1043(12), and 6.2862(6) Å, respectively. Moreover, the formal oxidation state of iron in [FeCl₄]⁻ as well as the coordination geometry in its vicinity was also proved by ⁵⁷Fe Mössbauer spectroscopy in the case of 9.     

Li3V2(PO4)3/C和Li2.5Na0.5V2(PO4)3/C的结构和电化学性能的比较研究

采用溶胶-凝胶法合成了锂离子正极材料Li3V2(PO4)3/C(LVP/C)及Li2.5Na0.5V2(PO4)3/C,并用XRD、循环伏安及交流阻抗等方法,研究了大量Na+掺杂对材料结构和电化学性能影响。结果表明,大量钠离子的掺杂会使LVP结构由单斜向菱方转变。掺杂化合物Li2.5Na0.5V2(PO4)3/C在0.5 C充电1 C放电时,首次放电容量为118 mAh.g-1,50次循环后容量保持率为92.4%,并发现与单斜LVP存在多个放电平台不同,Li2.5Na0.5V2(PO4)3/C仅在3.7 V处有一个放电平台。     

Anionic high-temperature conduction in single crystals of nonstoichiometric phases R1 ? y M y F3 ? y (R = La-Lu, M = Ca, Sr, Ba) with the tysonite (LaF3) structure

Electrophysical properties of single crystals of nonstoichiometric phases R_{1 − y} M _y F_{3 − y} , where R = La-Lu, M = Ca, Sr, or Ba, with the tysonite (LaF₃) structure, which are present in a metastable state after being grown and cooled, are measured in the temperature interval extending from 300 to 1073 K. It is discovered that, during a sufficiently long high-temperature investigation, solid solutions R_{1 − y} Ca _y F_{3 − y} , where R = Tb, Dy, or Ho, undergo irreversible variations in the phase composition in the temperature region 723 to 823 K. This level of temperatures, which correspond to partial decomposition of phases R_{1 − y} Ca _y F_{3 − y} with the rare-earth elements of the end of the period, lies above the temperatures to which the fluoride solid electrolytes are usually heated when used in solid-state electrochemical devices. The temperature and concentration dependences of the phases’ electroconduction are explained in the framework of the vacancy mechanism of anionic transport. Original Russian Text ? N.I. Sorokin, B.P. Sobolev, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 4, pp. 420–431. The paper is dedicated to the memory of Prof. M.W. Breiter, formerly of the Vienna Technical University, Austria.     

Structure and luminescence properties of silver-doped NaY(PO3)4 crystal

Single crystals of NaY(PO₃)₄ and Ag_0.07Na_0.93Y(PO₃)₄ have been synthesized by flux method. These new compounds turned out to be isostructural to NaLn(PO₃)₄, with Ln=La, Nd, Gd and Er [monoclinic, P2₁/n, a=7.1615(2) Å, b=13.0077(1) Å, c=9.7032 (3) Å, β=90.55 (1)°, V=903.86(14) Å³ and Z=4]. The structure is based upon long polyphosphate chains running along the shortest unit-cell direction and made up of PO₄ tetrahedra sharing two corners, linked to yttrium and sodium polyhedra. Infrared and Raman spectra at room temperature confirms this atomic arrangement. The luminescence of silver ions was reported in metaphosphate of composition Ag_0.07Na_0.93Y(PO₃)₄. One luminescent centre was detected and assigned to single Ag⁺ ions.     

Synthesis, crystal structure and spectroscopy properties of Na3AZr(PO4)3 (A=Mg, Ni) and Li2.6Na0.4NiZr(PO4)3 phosphates

Na₃AZr(PO₄)₃ (A=Mg, Ni) phosphates were prepared at 750 °C by coprecipitation route. Their crystal structures have been refined at room temperature from X-ray powder diffraction data using Rietveld method. Li_2.6Na_0.4NiZr(PO₄)₃ was synthesized through ion exchange from the sodium analog. These materials belong to the Nasicon-type structure. Raman spectra of Na₃AZr(PO₄)₃ (A=Mg, Ni) phosphates present broad peaks in favor of the statistical distribution in the sites around PO₄ tetrahedra. Diffuse reflectance spectra indicate the presence of octahedrally coordinated Ni²⁺ ions.     

The application of the λ parameter method to calculation of the interaction energies between two plane parallel double layers for symmetric electrolytes

The λ parameter method had successfully been applied to calculate the interaction energies between two plane parallel double layers for symmetric electrolytes. When y ₀ and |y _d | ≤ 20, the number of the series terms required to obtain the interaction energies with six significant digits is not more than 4. If we regard the interaction energies as the function of the hyperbolic function tanh (y ₀/2) instead of tanh(y ₀/4), then calculating it with the aid of λ parameter method, we can obtain above results at once. This enables one to avoid the mathematical complexity of other methods.     

Thermodynamic Quantities and Defect Structure of La0.6Sr0.4Co1−yFeyO3−δ(y=0–0.6) from High-Temperature Coulometric Titration Experiments

The partial energies and entropies of O₂in perovskite-type oxides La_0.6Sr_0.4Co_1−yFe_yO_3−δ(y=0, 0.1, 0.25, 0.4, 0.6) were determined as a function of nonstoichiometryδby coulometric titration of oxygen in the temperature range 650–950°C. An absolute reference value ofδwas obtained by thermogravimetry in air. The nonstoichiometry at a given oxygen pressure and temperature decreases with iron contenty. At low nonstoichiometries the oxygen chemical potential decreases withδ. The observed behavior can be interpreted by assuming random distribution of oxygen vacancies, an electronic structure with both localized donor states on Fe, and a partially filled itinerant electron band, of which the density of states at the Fermi level scales with the Co content. The energy of the Fe states is close to the energy at the Fermi level in the conduction band. The observed trends of the thermodynamic quantities can be interpreted in terms of the itinerant electron model only when the iron content is small. At high values ofδthe chemical potential of O₂becomes constant, indicating partial decomposition of the perovskite phase. The maximum value ofδat which the compositions are single-phase increases with temperature.