The intercalation of transition metal salen complexes into layered MoS2

Exfoliation-restack method has been employed to synthesize the intercalation compounds based on the cationic complexes [M(Salen)]⁺ (M = Mn³⁺, Fe³⁺, Co³⁺; Salen = N, N′-ethylene-bis(salicylaldimine)) into the layered MoS₂. Their conductivity is in the range of 0.04–0.1 S/cm, which is much higher than the pristine MoS₂. Magnetic measurement indicated that the intercalation compounds [Mn(Salen)]_0.18MoS₂ · 0.25H₂O and [Fe(Salen)]_0.12MoS₂ · 0.3H₂O exhibit the temperature-dependent paramagnetism, which obviates from the Curie–Weiss law due to the temperature-independent paramagnetism of the exfoliated MoS₂ slabs, while [Co(Salen)]_0.14MoS₂ · 0.5H₂O exhibits the almost temperature-independent paramagnetism. All three intercalation compounds do not show magnetic spin crossover behavior.     

Reactions of metallocenes during intercalation into the layered TiSe2 lattice

The intercalation of metallocenes (Cp₂Co, Cp₂Fe, and Cp₂Ni, where Cp is η⁵-C₅H₅) from the gas phase into the TiSe₂ lattice and of cobaltocene from solutions in acetonitrile, carbon tetrachloride, and chloroform into TiSe₂ was studied. The insertion of metallocenes from the gas phase into the TiSe₂ lattice gives rise to the TiSe₂(Cp₂M)_0.3 compounds (M = Co or Fe) having the same stoichiometry. The reactions with the use of acetonitrile as the solvent for metallocenes, which facilitates the insertion, afford not only the intercalation complex but also the reaction product of metallocene and acetonitrile, viz., (η ⁵-C₅H₅)Co(η⁴-C₅H₅CH₂CN) (1). In the reactions of cobaltocene with chloroform or carbon tetrachloride in the presence of titanium diselenide, only the addition product, viz., (η ⁵-C₅H₅)Co(η₄-C₅H₅CCl₃) (2), was isolated. The structures of complexes 1 and 2 were studied by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–880, May, 2007.     

Melt intercalation of polystyrene in layered silicates

We have studied the melt intercalation of polystyrene into organically modified sodium bentonite, a layered, mica-type silicate, using a variety of techniques. Wide-angle X-ray scattering experiments on polymer/silicate hybrid samples demonstrate that intercalation of polymer chains leads to an ∼25% increase in the spacing between silicate layers. The magnitude of this increase, compared with the radius of gyration of the melt polymer, implies a flattened conformation of chains in the galleries. Low voltage scanning electron microscopy reveals voids in the intercalated hybrid matrix that correspond to regions where pristine polymer was present in the physical mixture of polymer and silicate before intercalation. Differential scanning calorimetry shows that only unintercalated polymer contributes to the measured glass transition trace, so that the magnitude of the trace is diminished upon intercalation. © 1996 John Wiley & Sons, Inc.     

Electrochemical intercalation of lithium into nanocrystalline ceria

The specifics of electrochemical lithium intercalation into nanocrystalline ceria were studied. The lithium capacity of CeO_{2 − x} is discovered to increase systematically as the nanoparticle size shifts down, indicating the potential of nanocrystalline ceria for use in electrochromic applications.     

Electrochemical intercalation of lithium into carbon nanoparticles

This paper reports properties of carbon nanoparticles used as anode of lithium-ion battery. It shows that carbon nanoparticles have a high first-charge capacity and good potential for cycling and, if properly modified, are a promising anode material for lithium-ion batteries. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 8, pp. 999–1001. The text was submitted by the authors in English.     

Atomic scale understanding of aluminum intercalation into layered TiS_2 and its electrochemical properties

正Aluminum-ion batteries (AIBs) are attracting great attentions recently because of the high volumetric capacity,natural abundance of Al and operational safety.Using metallic A1 as anode,the development of suitable cathode materials is a key issue to build an advanced AIBs system [1,2].Up to now,various materials have been studied as cathode materials for AIBs,including graphite [3,4],metal oxides [5-7],and metal sulfides [8,9].However,few of them can meet the application requirements,and the theoretical understanding of their electrochemical mechanism is limited.     

Electrochemical intercalation reaction of lithium into sulfides of nonlayer structure: I. Lithium intercalation in lead sulfide

The reaction mechanism of cell Li/PbS has been studied with coulombic titration, cyclic voltammetry and X-ray diffraction methods. It was found that in the first stage of discharge (0< y ≤1.5), the intercalation of lithium into lead sulfide took place. The X-ray diffraction patterns showed that the main crystalline structure of PbS remained unchanged after lithiation, and the lithium intercalated probably locates in the center of the cubic-interspace of the crystal. The intercalation free energy of Li into PbS forming LiPbS was found to be ?300.48 KJ·mol^?1 (at 25°C). The chemical diffusion coefficient of lithium in Li_yPbS (0<y≤1) was determined by electrochemical method to be about 10^?11 cm²S-1.     

Electrochemical behavior of layered annulenes

The cyclic voltammetric behavior of a series of dimeric [14] annulenes was examined and compared with the monomer. The data suggest a signigficant degree of interaction between the annulene rings when a three-carbon chain connects them, little or no interaction with an eight-carbon chain, and weak interaction with a four-carbon chain.     

Preparation of protein-silicate hybrids from polyamine intercalation of layered montmorillonite

Hybrids of the model BSA protein and layered silicate clay with d spacing of approximately 62 A were prepared from either direct or stepwise intercalation. The pristine montmorilloinite (Na+-MMT) was first modified by poly(oxyalkylene)-amine salts (POP- and POE-amine) of 2000 g/mol Mw to a gallery-expanded silicate (d spacing=53 and 18 A, respectively), which became accessible for BSA protein embedding. Subsequent BSA substitution allowed the embedding of the protein into the layered clay galleries in an uncompressed conformation. The stepwise process of embedding large molecules into the silicate gallery provides a new method for synthesizing biomaterial/clay hybrids potentially useful in drug delivery or biomedical design.     

The intercalation of metalloporphyrin complex anions into layered double hydroxides

Investigations to elucidate the structures of the cobalt(III) and manganese(III) complexes of tetra(p-sulfonatophenyl)porphinate anions (M(III)TSPP; M = Co and Mn), intercalated in Mg-Fe/Cl and Mg-Al/Cl layered double hydroxides (LDHs) have been carried out. Powder X-ray diffraction analysis, IR and UV-vis diffuse reflectance spectroscopy of Co(III)TSPP and Mn(III)TSPP intercalated into the interlayer spaces of LDH resulted in their perpendicular alignment against the host layers in the plane of the hybrid.     

Swelling, intercalation, and exfoliation behavior of layered ruthenate derived from layered potassium ruthenate

The intercalation chemistry of a layered protonic ruthenate, H_0.2RuO_2.1·nH₂O, derived from a layered potassium ruthenate was studied in detail. Three phases with different hydration states were isolated, H_0.2RuO_2.1·nH₂O (n=0, 0.5, 0.9), and its reactivity with tetrabutylammonium ions (TBA⁺) was considered. The layered protonic ruthenate mono-hydrate readily reacted with TBA⁺, affording direct intercalation of bulky tetrabutylammonium ions into the interlayer gallery. Fine-tuning the reaction conditions allowed exfoliation of the layered ruthenate into elementary nanosheets and thereby a simplified one-step exfoliation was achieved. Microscopic observation by atomic force microscopy and transmission electron microscopy clearly showed the formation of unilamellar sheets with very high two-dimensional anisotropy, a thickness of only 1.3±0.1 nm. The nanosheets were characterized by two-dimensional crystallites with the oblique cell of a=0.5610(8) nm, b=0.5121(6) nm and γ=109.4(2)° on the basis of in-plane diffraction analysis.     

Electrochemical properties of submicro-sized layered LiNi0.5Mn0.5O2

Submicro-sized layered LiNi_0.5Mn_0.5O₂ was synthesized via an improved solid-state reaction, in which at first a precursor mixed by nickel manganese double hydroxide with lithium hydroxide solution was prepared in order to make the fully contact between these materials, and then was calcined at different temperatures. The heat treatment process and the crystal structure of materials were investigated by DTA, TGA, and XRD methods. The SEM images show that the particles of layered LiNi_0.5Mn_0.5O₂ are submicrometer in size. It was found that the layered LiNi_0.5Mn_0.5O₂ synthesized at 750 °C for 24 h in oxygen atmosphere presents the best electrochemical performance, which delivers an initial discharge capacity of 153 mAh/g in the charge/discharge potential region (vs. Li) of 2.5–4.3 V, and exhibits good cycle stability.     

Electrochemical and structural evolution of structured V_2O_5 microspheres during Li-ion intercalation

With the development of stable alkali metal anodes,V₂O₅ is gaining traction as a cathode material due to its high theoretical capacity and the ability to intercalate Li,Na and K ions.Herein,we report a method for synthesizing structured orthorhombic V₂O₅ microspheres and investigate Li intercalation/deintercalation into this material.For industry adoption,the electrochemical behavior of V₂O₅ as well as structural and phase transformation attributing to Li intercalation reaction must be further investigated.Our synthesized V₂O₅ microspheres consisted of small primary particles that were strongly joined together and exhibited good cycle stability and rate capability,triggered by reversible volume change and rapid Li ion diffusion.In addition,the reversibility of phase transformation(a,e,d,c and xLixV₂O₅)and valence state evolution(5+,4+,and 3.5+)during intercalation/de-intercalation were studied via in-situ X-ray powder diffraction and X-ray absorption near edge structure analyses.     

Interdigitation, interpenetration and intercalation in layered cuprous tricyanomethanide derivatives

Reaction of Cu(I), tricyanomethanide (tcm , C(CN)3-) and L = either hexamethylenetetramine (hmt), 4,4'-bipyridine (bipy) or 1,2-bis(4-pyridyl)ethene (bpe) gives crystals of [Cu(tcm)(hmt)] (1), [Cu(tcm)(bipy)] (2) and [Cu(tcm)(bpe)] x 0.25 bpe x 0.5 MeCN (3), respectively. Crystal structure analysis shows 1-3 all contain closely related puckered (4,4) sheets composed of tetrahedral Cu(I) ions bridged by 2-connecting tcm- and L. The crystal packing, however, varies markedly with L. In 1 the sheets interdigitate in pairs. In 2 the sheets participate in parallel interpenetration in pairs. In 3 guest bpe and MeCN molecules are intercalated in channels formed by the stacking of the sheets.     

Analytical methods vs. numerical results for reacting layered systems

We consider here reactions in layered systems. We model a situation in which the mixing of the reactants precedes the chemical reaction and show that the overall decay kinetics is determined by the initial striation thickness distribution. Thus the kinetics is controlled by the diffusive motion of the spatial inhomogeneities (clusters). Different numerical approaches to the problem are discussed and the results of the numerical modeling are compared with the analytical considerations.     

The intercalation of bicyclic and tricyclic carboxylates into layered double hydroxides

Twenty-four nanocomposites built from layered double hydroxides and bicyclic and tricyclic carboxylates have been synthesised for the first time. Eight carboxylates were successfully intercalated into [LiAl₂(OH)₆]Cl·yH₂O, [Ca₂Al(OH)₆]NO₃·yH₂O, and [Mg₂Al(OH)₆]NO₃·yH₂O, and the products fully characterised. Guest species incorporated include 1-adamantane carboxylate (1-AC) and 5-norbornene-2-endo-3-exo-dicarboxylate. In some cases, carbonate anions were co-intercalated with the organic guest, and in others poorly crystalline aluminium hydroxides formed as by-products. Sharper resonances were observed in the ¹³C solid-state NMR spectra of the 1-AC intercalates than in the spectrum of pure 1-AC, suggesting increased order in the arrangement of the cyclic cages in the intercalates. Where possible, time-resolved in situ X-ray diffraction was employed to study the nanoscopic steps involved in the intercalation reactions. These investigations showed that the reactions are one-step processes, proceeding directly to the fully exchanged intercalate with no intermediate phases. The intercalation processes were found to be nucleation controlled.     

Electrochemical intercalation and deintercalation of NaxMnO2 bronzes

Various Na_xMnO₂ bronzes have been electrochemically deintercalated. Na_0.40MnO₂ has a channel structure which is maintained for a large intercalation range (0.30 ≤ × ≤ 0.58). In order to explain the upper intercalation limit, an ordered sodium distribution between two types of Na⁺ sites is proposed. Na_0.70MnO₂ and α-NaMnO₂ have lamellar structures of P2 and 0′3 types. During intercalation the original P2 type is maintained for 0.45 ≤ × ≤ 0.85 while two reversible structural transitions are observed from α-NaMnO₂. A similar behavior occurs during the deintercalation of the high-temperature β-NaMnO₂ variety. In each case of the structural transition the double octahedral layers remain unchanged. Electronic localization (increased by Mn³⁺ Jahn—Teller effect) tends to trap the Na⁺ ions and therefore increases the relaxation time of the investigated materials.     

锂在非层状硫化物中的电化学嵌入反应I:锂在硫化铅中的嵌入过程

通过库伦滴定、三角波电位扫描和X射线衍射物相分析,研究了Li/PbS电池的阴极反应机理.发现在该电池放电的第一个阶段(放电深度小于1.5),阴极上发生的是锂嵌入硫化铅晶格的反应,并且锂嵌入后硫化铅的主晶格结构基本未变,锂进入了晶体的立方体间隙中心位置.测得锂嵌入硫化铅生成LiPbS的嵌入自由能为-300.48kJ.mol^-^1(25℃),锂在LiyPbS(0相似文献   

Inclusion of aramid chains into the layered silicates through solution intercalation route

Aramid–organoclay nanocomposites were fabricated through solution intercalation technique. Montmorillonite was modified with p-amino benzoic acid in order to have compatibility with the matrix. The effect of clay dispersion and the interaction between clay and polyamide chains on the properties of nanocomposites were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), tensile testing of thin films, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and water uptake measurements. Excessive clay dispersion was achieved even on the addition of high proportions of clay. The structural investigations confirmed the formation of delaminated nanostructures at low clay contents and disordered intercalated morphology at higher clay loadings. The tensile behavior and thermal stability significantly amplified while permeability reduced with increasing dispersibility of organoclay in the polyamide matrix.     

Thermal characterization of the intercalation compound ofp-toluenesulfonate into a layered double hydroxide

On intercalation ofp-toluenesulfonate (PTS) into Mg/Al (0.73/0.27) layered double hydroxide (LDH), the layer expanded from 4.77 Å to 17.7 Å, indicating that the plane of PTS was perpendicular to the plane of the LDH layers. Thermal treatment of the PTS intercalate resulted in 82% of the included PTS being evolved as decomposition products. This value was higher than the value of 32.5% obtained with sodium PTS and 43.8% with a mixed sample of PTS and Mg/Al (0.73/0.27) LDH. It was considered that the intercalated PTS in Mg/Al (0.73/0.27) LDH was easy to decompose because interaction between intercalated PTS and Mg/Al (0.73/0.27) LDH was smaller than that between sodium and PTS in sodium PTS.