Intercalation Chemistry Research Articles

Lithium Insertion Behavior of Nanoscopic Co3O4Prepared with Avian Egg Membrane as a Template

particles were prepared using avian egg membrane as a template at 800 °C. The preparedmaterials were subjected to XRD, SEM, TEM and Raman spectroscopic studies. Cyclic voltammetry studyshows a single step oxidation and reduction process. Electrochemical lithium insertion behavior of thematerials was examined in coin cells of the 2032 configuration. The material showed a discharge capacity 600mAh/g even after 20 cycles. Key Words: Oxides, Nanostructures, Electron microscopy, Electrochemical propertiesIntroductionThe evolution of lithium-ion batteries can be traced toproblems associated with the use of metallic lithium inrechargeable lithium batteries. Although graphite is the mostpopular anode material in lithium-ion batteries, with aspecific capacity of only 372 mAh/g, it fares poorly com-pared to metallic lithium with a specific capacity of 3862mAh/g. Thus, great efforts are being made towards develop-ment of a variety of other anode materials such as lithium-alloying metals, electro-active polymers and silicon. Researchin such high-capacity anode materials is driven by demand-ing power requirements in emerging applications as inelectric vehicles. Conventional wisdom on electrochemicalinsertion reactions in lithium-ion batteries requires electro-nically conducting electrode materials with crystallographicvoids that can support lithium diffusion. In that sense,interstitial-free 3d-metal oxide structures are consideredunsuitable for intercalation chemistry. Recently, however,there has been a spurt in papers reporting the use of severaloxides, oxysalts, nitrides, fluorides, phosphides, sulphidesand borides as anode materials for lithium-ion batterychemistry.

Electrolyte Additive in Support of 5 V Li Ion Chemistry

An electrolyte additive based on highly fluorinated phosphate ester structure was identified as being able to stabilize carbonate-based electrolytes on class cathode surfaces. The synthesis and structural analysis of the additive are described, and preliminary yet encouraging results from electrochemical characterization showed that this additive participates in forming a protective interphasial chemistry not only on transition metal oxide cathode at high voltage ( vs Li) but also on graphitic graphite at low voltage ( vs Li), making it possible to formulate an electrolyte supporting reversible -intercalation chemistry in the coveted region.

Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials

To evaluate the potential of Na-ion batteries, we contrast in this work the difference between Na-ion and Li-ion based intercalation chemistries in terms of three key battery properties—voltage, phase stability and diffusion barriers. The compounds investigated comprise the layered AMO2 and AMS2 structures, the olivine and maricite AMPO4 structures, and the NASICON A3V2(PO4)3 structures. The calculated Na voltages for the compounds investigated are 0.18–0.57 V lower than that of the corresponding Li voltages, in agreement with previous experimental data. We believe the observed lower voltages for Na compounds are predominantly a cathodic effect related to the much smaller energy gain from inserting Na into the host structure compared to inserting Li. We also found a relatively strong dependence of battery properties on structural features. In general, the difference between the Na and Li voltage of the same structure, ΔVNa–Li, is less negative for the maricite structures preferred by Na, and more negative for the olivine structures preferred by Li. The layered compounds have the most negative ΔVNa–Li. In terms of phase stability, we found that open structures, such as the layered and NASICON structures, that are better able to accommodate the larger Na+ ion generally have both Na and Li versions of the same compound. For the close-packed AMPO4 structures, our results show that Na generally prefers the maricite structure, while Li prefers the olivine structure, in agreement with previous experimental work. We also found surprising evidence that the barriers for Na+ migration can potentially be lower than that for Li+ migration in the layered structures. Overall, our findings indicate that Na-ion systems can be competitive with Li-ion systems.

New insights into the intercalation chemistry of Al(OH)3

This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

ChemInform Abstract: Intercalation Chemistry in a LDH System: Anion Exchange Process and Staging Phenomenon Investigated by Means of Time‐Resolved, in situ X‐Ray Diffraction

AbstractReview: 73 refs.

ChemInform Abstract: Intercalation Chemistry. Useful Reactions, New Materials and Enhanced Physical Properties

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Differentiating Contributions to “Ion Transfer” Barrier from Interphasial Resistance and Li+ Desolvation at Electrolyte/Graphite Interface

Efforts were made to differentiate the contributions to the so-called "ion transfer" barrier at the electrolyte/graphite junction from two distinct processes: (1) desolvation of Li(+) before it enters graphene interlayer and (2) the subsequent migration of bare Li(+) through the ad hoc interphase. By leveraging a scenario where no substantial interphase was formed on Li(+) intercalation hosts, we were able to quantify the distribution of "ion transfer" activation energy between these two interfacial processes and hence identify the desolvation process of Li(+) as the major energy-consuming step. The result confirmed the earlier belief that the rate-determining step in the charging of a graphitic anode in Li(+) intercalation chemistry relates to the stripping of solvation sheath of Li(+), which is closely interwoven with the interphasial resistance to Li(+) migration.

Electrolytes and Interphasial Chemistry in Li Ion Devices

Since its appearance in 1991, the Li ion battery has been the major power source driving the rapid digitalization of our daily life; however, much of the processes and mechanisms underpinning this newest battery chemistry remains poorly understood. As in any electrochemical device, the major challenge comes from the electrolyte/electrode interfaces, where the discontinuity in charge distribution and extreme disequality in electric forces induce diversified processes that eventually determine the kinetics of Li+ intercalation chemistry. This article will summarize the most recent efforts on the fundamental understanding of the interphases in Li ion devices. Emphasis will be placed on the formation chemistry of the so-called “SEI” on graphitic anode, the effect of solvation sheath structure of Li+ on the intercalation energy barrier, and the feasibility of tailoring a desired interphase. Biologically inspired approaches to an ideal interphase will also be briefly discussed.

Synthetic Fabrication of Nanoscale MoS2-Based Transition Metal Sulfides

Transition metal sulfides are scientifically and technologically important materials. This review summarizes recent progress on the synthetic fabrication of transition metal sulfides nanocrystals with controlled shape, size, and surface functionality. Special attention is paid to the case of MoS2 nanoparticles, where organic (surfactant, polymer), inorganic (support, promoter, doping) compounds and intercalation chemistry are applied.

Intercalation Chemistry and Electronic Structure of Graphite-Like Layered Material BC2N

A graphite-like layered material of composition , which is called in this paper, was prepared by a chemical vapor deposition method at 1770–2220 K. Lithium (Li) and potassium (K) were intercalated into by an electrochemical method and a vapor-phase reaction, respectively, to make the first-stage compounds with interlayer spacings similar to those of the first-stage graphite intercalation compounds. Sodium (Na) was intercalated into by the electrochemical method as well as the vapor-phase reaction, whereas Na was hardly intercalated into graphite. The X-ray diffraction analysis and an electrochemical capacity suggested that the Na-intercalated was a mixture of the first- and second-stage compounds. X-ray absorption spectroscopy indicated that an unoccupied π∗ orbital of showed a relatively strong intensity, and the bottom of the orbital was at an energy lower than each bottom of graphite, noncrystalline carbon, and . These results suggested that alkali metals including Na could donate electrons to more efficiently than the other host materials. Thus, the intercalation of alkali metal into proceeds more effectively than the other host materials.

Intercalation chemistry in a LDH system: anion exchange process and staging phenomenon investigated by means of time-resolved, in situ X-ray diffraction

Using time-resolved, in situ energy-dispersive X-ray diffraction (EDXRD), the formation of interstratified LDH structures, with alternate interlayer spaces occupied by different anions, have been demonstrated during anion exchange reactions. Novel hybrid LDH nanostructures can thus be prepared, combining the physicochemical properties of two intercalated anions plus those of the LDH host. A general trend is that inorganic-inorganic anion exchange reactions occur in a one-step process while inorganic-organic exchanges may proceed via a second-stage intermediate, suggesting that staging occurs partly as a result of organic-inorganic separation. Yet, other influencing parameters must be considered such as LDH host composition, LDH affinity for different anions and LDH particle size as well as extrinsic parameters like the reaction temperature. Hence, a correlation between the occurrence of staging phenomenon and the difficulty of the exchange of the initial anion is observed, suggesting that staging is needed to overcome the energy barrier in the case of the exchange by organic anions. Notwithstanding the LiAl(2) system, staging has mainly been observed with Zn(2)Cr LDH host so far, a peculiar LDH composition with a unique Zn/Cr ratio of two and a local order of the cations within the hydroxide layers. The formation of a higher order-staged intermediate than stage two, observed during the exchange reaction of CO(3)(2-) or SO(4)(2-) anions with Zn(2)Cr-tartrate, is in favour of a Daumas-Herold model although this model implies a bending of LDH layers. The analysis of the X-ray powder diffraction pattern of Zn(2)Cr-Cl/tartrate second-stage intermediate, isolated almost as a pure phase during the exchange of Cl(-) with tartrate anions in Zn(2)Cr LDH, indicates a disorder in the stacking sequence and a relative proportion of the two kinds of interlayers slightly different from 50/50. Besides, the microstructural analysis of the XRD pattern reveals a great reduction of the stacking thickness during the anion exchange process but with no change of the in-plane coherent length, therefore no in-plane deformation of LDH host layers. Finally, the anion exchange properties of Zn(2)Cr-Cl/tartrate, investigated by means of EDXRD, show highly selective anion-exchange reactions, leading to the formation of new second-stage intermediates that cannot be prepared starting from the mono-intercalated Zn(2)Cr-Cl. This "Zn(2)Cr-Cl/tartrate approach" might constitute a new route for the synthesis of various mixed organic-inorganic anions-exchanged forms of LDH.

The enhanced alcohol-sensing response of ultrathinWO3 nanoplates

Chemical sensors based on semiconducting metal oxide nanocrystalsare of academic and practical significance in industrial processing andenvironment-related applications. Novel alcohol response sensors using two-dimensionalWO3 nanoplates as active elements have been investigated in this paper. Single-crystallineWO3 nanoplates were synthesized through a topochemical approach on the basisof intercalation chemistry (Chen et al 2008 Small 4 1813). The as-obtainedWO3 nanoplate pastes were coated on the surface of anAl2O3 ceramicmicrotube with four Pt electrodes to measure their alcohol-sensing properties. The results show thatthe WO3 nanoplate sensors are highly sensitive to alcohols (e.g., methanol, ethanol,isopropanol and butanol) at moderate operating temperatures (260–360 °C). Forbutanol, the WO3 nanoplate sensors have a sensitivity of 31 at 2 ppm and 161 at 100 ppm, operating at300 °C. For otheralcohols, WO3 nanoplate sensors also show high sensitivities: 33 for methanol at 300 ppm, 70 for ethanol at200 ppm, and 75 for isopropanol at 200 ppm. The response and recovery times of theWO3 nanoplate sensors are less than 15 s for all the test alcohols. A good linear relationship between thesensitivity and alcohol concentrations has been observed in the range of 2–300 ppm, whereas theWO3 nanoparticle sensors have not shown such a linear relationship. The sensitivities of theWO3 nanoplate sensors decrease and their response times become short when the operatingtemperatures increase. The enhanced alcohol-sensing performance could be attributed to theultrathin platelike morphology, the high crystallinity and the loosely assembling structure of theWO3 nanoplates, due to the advantages of the effective adsorption and rapid diffusion of thealcohol molecules.

Surface and Intercalation Chemistry of Polycarboxylate Copolymers in Cementitious Systems

The Ca–Al‐layered double hydroxide, the so‐called AFm phase, is a product of cement hydration. It is shown that the interaction of this phase with anionic polycarboxylate ether (PCE)‐based dispersant polymers is not a simple adsorption but a more complex intercalation phenomenon leading to the transient sequestration of the PCE within the AFm crystallites. As a result, part of the PCE is immobilized, forming a layered organo‐mineral composite, and does not play its role of a dispersing agent. This article presents, along general considerations on the links between cement chemistry and rheology, a detailed investigation of the formation, structure, and stability of a pure poly(methacrylate‐g‐PEO)/hydrocalumite composite obtained by coprecipitation. The predictions of scaling laws derived from models of conformation of comb copolymers in solution were tested against small‐angle X‐ray diffraction, transfer of populations by double‐resonance nuclear magnetic resonance, and small‐angle neutron scattering experimental results. A model of adsorbed polymers in a configuration of a flexible chain of hemispheric cores is proposed and appears to be compatible with the observed interlayer spacings in the range of several nanometers. Finally, these phases are shown to persist for several hours in the presence of sulfate ions.

New ramsdellites LiTi 2−yV yO 4 (0≤ y≤1): Synthesis, structure, magnetic properties and electrochemical performances as electrode materials for lithium batteries

The new ramsdellite series LiTi 2− y V y O 4 (0≤ y≤1) has been prepared by conventional solid state chemistry techniques and was characterized by X-ray powder diffraction and electron diffraction. To our knowledge, this is the first report on ramsdellites containing vanadium. The magnetic behaviour of these ramsdellites is strongly influenced by its vanadium content. In this sense, LiTi 2O 4 ( y=0) exhibits metallic-like temperature independent paramagnetism, but d electrons tend to localize with increasing V content. LiTiVO 4, though also paramagnetic, follows then the Curie–Weiss law. The crossover from delocalized to localized electrons is observed between compositions y=0.6 and 0.8. For y≥0.8 the magnetic results evidence an isovalent substitution mechanism of trivalent Ti by V. The electrochemical lithium intercalation and deintercalation chemistry of LiTi 2− y V y O 4 is grouped into two different operating voltage regions. Reversible lithium deintercalation of vanadium-substituted ramsdellite titanates LiTi 2− y V y O 4 in the high voltage range 2–3 V vs. Li occurs in two main steps, one at about 2 V and the other at about 3 V. The 3 V process capacity increases with the vanadium content, while the 2 V capacity decreases at the same time. The vanadium to titanium substitution rate in LiTi 2O 4 was found to be beneficial to the specific energy in as much as a 50% increase (1 V) of the working voltage is observed. On the other hand, reversible lithium intercalation in vanadium-substituted ramsdellite titanates LiTi 2− y V y O 4 in the low voltage range 1–2 V vs. Li occurs in one main single step, in which the capacity is not affected by the vanadium content, although vanadium-doping produces an improved capacity retention with an excellent cycling behaviour observed for y≤0.6.

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· nH 2O, derived from a layered potassium ruthenate was studied in detail. Three phases with different hydration states were isolated, H 0.2RuO 2.1· nH 2O ( 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.

Whether EC and PC Differ in Interphasial Chemistry on Graphitic Anode and How

Efforts were made to answer a question that has been puzzling the electrochemical community since the birth of Li-ion battery chemistry: How do ethylene carbonate (EC) and propylene carbonate (PC), with such negligible structural differences, differ so much in surface behavior on graphitic anodes that one leads to reversible Li-ion intercalation chemistry, while the other only leads to graphene structure disintegration? Through the comparative characterization of reference semicarbonate compounds and interphasial species directly collected from cycled graphitic anodes, the origin of the above distinct interphasial stabilities was tentatively attributed to the bulk physicochemical properties of the single-electron reduction products of EC and PC, rather than from the difference in interphasial reduction pathways.

X-ray diffraction studies of electrochemical graphite intercalation compounds of ionic liquids

Electrochemical intercalation studies are used to characterize a series of ionic liquids composed of a variety of cationic and anionic species. Electrochemically, the ionic liquids are characterized by cyclic voltammograms and charge–discharge experiments for the intercalation and de-intercalation of the various cationic and anionic species into graphite. X-ray structure analysis is also performed to determine the relationship between the electrochemical behaviour of the ionic liquids, and the formation of intercalated graphitic compounds. Two different types of imidazolium cations are studied, specifically the di- and trisubstituted imidazolium. These cations are paired with the following anions: tetrafluoroborate, hexafluorophosphate, bis(trifluoromethanesulfonyl)imide, bis(perfluoroethanesulfonyl)imide, nitrate and hydrogen sulfate. Results indicate stronger intercalation chemistry for the trisubstituted imidazoliums, correlating with the greater charge–discharge efficiencies found for these types of ionic liquids. Many of the anions exhibit very poor charge–discharge efficiencies, correlating to very poorly formed graphite intercalates. The exception to this is the hydrogen sulfate intercalate, which had low charge–discharge efficiencies but formed a well defined graphite intercalate. Only the imide based anions exhibited both high charge–discharge efficiencies and the formation of a clearly defined graphite intercalate.

Preparation of Rh-TPPTS complex intercalated layered double hydroxide and influences of host and guest compositions on its catalytic performances in hydroformylation reaction

Based on the concept of intercalation chemistry of layered double hydroxides (LDHs), RhCl(CO)-(TPPTS)2(TPPTS: P(m-C6H4SO3Na)3) and TPPTS co-intercalated LDHs were successfully synthesized by in situ complexation method. Characterizations of structure and composition of composite materials by powder XRD, FT-IR, and ICP-AES techniques confirmed the supramolecular structures of the catalytic species intercalated LDHs. The correlation between catalytic performance of intercalated catalyst and the composition of both host layers and interlayer guest species was also investigated.

Synthesis, Structure and Electrochemical Lithium Intercalation Chemistry of Ramsdellite‐Type LiCrTiO4

AbstractLiCrTiO4, which crystallizes in the orthorhombic ramsdellite structure, has been obtained by heating spinel LiCrTiO4 at 1250 °C in air. The refined cell parameters are a = 4.9835(6) Å, b = 9.5095(8) Å and c = 2.9282(2) Å, space group Pbnm, as determined from Rietveld refinement of X‐ray powder diffraction data. The intercalation chemistry of LiCrTiO4 has been investigated. Lithium can be extracted from LiCrTiO4 due to oxidation of CrIII at rather high potential 4 V. On the other hand, lithium intercalation proceeds readily at 1.5 V due to the reduction of tetravalent titanium. Regarding practical applications, as an electrode for lithium rechargeable batteries, specific capacities of 100 and 120 mAh·g−1 are developed at 0.1 mA·cm−2, respectively. These findings point out that the ramsdellite form of LiCrTiO4 may be an ambivalent electrode, which can be used either as the positive electrode or the negative electrode of a lithium ion rechargeable battery.

Structure, properties and corrosion resistivity of polymeric nanocomposite coatings based on layered silicates

This paper reviews the recent research and development of polymeric nanocomposite coatings based on layered silicates. In the past few decades, extensive research activities have been conducted on clay minerals due to their unique layered structure, rich intercalation chemistry and availability at low cost, environmental stability, and good processability. One of the most important categories of layered silicates is nanoclays. The nanoclay is considered as reinforcement for polymers in the manufacture of low-cost, lightweight and high performance nanocomposite coatings. In this paper, we try to introduce the structure, properties, and surface modification of clay minerals. Different properties of polymer clay nanocomposite coatings consisting of different polymers are also reviewed. These coatings may consist of conductive and nonconductive polymers. The corrosion resistance of each type is discussed separately. Some novel properties can be observed from the interaction of two dissimilar chemical components at the molecular level that posses enhancements in corrosion inhibition on metallic substrates. Finally, the prospective problems of industrial usage of these materials are mentioned.