F-doped orthorhombic Nb_(2)O_(5) exposed with 97% (100) facet for fast reversible Liþ-Intercalation

Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging Li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for Li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microflowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoflakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible Li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the Li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the Li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).

Li intercalation in an MoSe_(2) electrocatalyst:In situ observation and modulation of its precisely controllable phase engineering for a high-performance flexible Li-S battery

Sophisticated efficient electrocatalysts are essential to rectifying the shuttle effect and realizing the high performance of flexible lithium-sulfur batteries(LSBs).Phase transformation of MoSe_(2) from the 2H phase to the 1T phase has been proven to be a significant method to improve the catalytic activity.However,precisely controllable phase engineering of MoSe_(2) has rarely been reported.Herein,by in situ Li ions intercalation in MoSe_(2),a precisely controllable phase evolution from 2H-MoSe_(2) to 1T-MoSe_(2) was realized.More importantly,the definite functional relationship between cut-off voltage and phase structure was first identified for phase engineering through in situ observation and modulation methods.The sulfur host(CNFs/1T-MoSe_(2))presents high charge density,strong polysulfides adsorption,and catalytic kinetics.Moreover,Li-S cells based on it display capacity retention of 875.3mAh g^(-1) after 500 cycles at 1 C and an areal capacity of 8.71mAh cm^(-2) even at a high sulfur loading of 8.47mg cm^(-2).Furthermore,the flexible pouch cell exhibiting decent performance will endow a promising potential in the wearable energy storage field.This study proposes an effective strategy to precisely control the phase structure of MoSe_(2),which may provide the reference to fabricate the highly efficient electrocatalysts for LSBs and other energy systems.

Electrochemically triggered decoupled transport behaviors in intercalated graphite:From energy storage to enhanced electromagnetic applications

Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could meeting the limit of electrical conductivity (~2.5×10^(4) S·cm^(−1)),although efforts have been made for achieving high-purity sp^(2) hybridized carbon.For manipulating the electrical conductivity of PG,a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of AlCl_(4)^(-)into the graphitic interlayers.With the stage evolution at different voltages,variable electrical and thermal transport behaviors could be achieved via controlling AlCl_(4)^(-)concentrations in the PG because of substantial variation in the electronic density of states.Such evolution leads to decoupled electrical and thermal transport (opposite variation trend) in the in-plane and out-of-plane directions,and the in-plane electrical conductivity of the pristine PG (1.25×10^(4) S·cm^(−1)) could be massively promoted to 4.09×10^(4) S·cm(AlCl_(4)^(-)intercalated PG),much better than the pristine bulk graphitic papers used for the electrical transport and electromagnetic shielding.The fundamental mechanism of decoupled transport feature and electrochemical strategy here could be extended into other anisotropic conductive bulks for achieving unusual behaviors.

Intercalation of hafnium oxide between epitaxially-grown monolayer graphene and Ir(111)substrate

Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we demonstrate a successful solution for the intercalation of hafnium oxide into the interface between full-layer graphene and Ir(111)substrate.We first intercalate hafnium atoms beneath the epitaxial graphene.The intercalation of the hafnium atoms leads to the variation of the graphene moire superstructure periodicity,which is characterized by low-energy electron diffraction(LEED)and lowtemperature scanning tunneling microscopy(LT-STM).Subsequently,we introduce oxygen into the interface,resulting in oxidization of the intercalated hafnium.STM and Raman's characterizations reveal that the intercalated hafnium oxide layer could effectively decouple the graphene from the metallic substrate,while the graphene maintains its high quality.Our work suggests a high-k dielectric layer has been successfully intercalated between high-quality epitaxial graphene and metal substrate,providing a platform for applications of large-scale,high-quality graphene for electronic devices.

Fault rupture propagation in soil with intercalation using nonlocal model and softening modulus modification

Fault rupture propagation is more complex in the overlying soil with intercalation than in homogeneous soil,and it is challenging to simulate this phenomenon accurately using the finite element method.To address this issue,an improved nonlocal model that incorporates softening modulus modification is proposed.The methodology has the advantage that the solutions are independent of both mesh sizes and characteristic lengths,while maintaining objective softening rates of materials.Using the proposed methodology,a series of numerical simulations are conducted to investigate the effects of different mechanical parameters,such as elastic modulus,friction angle and dilation angle of the soil within the intercalation,as well as the impact of geometries,such as the depth and thickness of the intercalation,on the fault rupture progress.This study not only provides significant insights into the mechanisms of fault rupture propagation,specifically in relation to intercalations,but also shows a great value in promoting the current research on fault rupture.

Synergistically coupling of graphene quantum dots with Zn-intercalated MnO2 cathode for high-performance aqueous Zn-ion batteries

Cost-effective,safe,and highly performing energy storage devices require rechargeable batteries,and among various options,aqueous zinc-ion batteries(ZIBs)have shown high promise in this regard.As a cathode material for the aqueous ZIBs,manganese dioxide(MnO_(2))has been found to be promising,but certain drawbacks of this cathode material are slow charge-transfer capability and poor cycling performance.Herein,a novel design of graphene quantum dots(GQDs)integrated with Zn-intercalated MnO_(2)nanosheets is put forward to construct a 3D nanoflower-like GQDs@ZnxMnO_(2)composite cathode for aqueous ZIBs.The synergistic coupling of GQDs modification with Zn intercalation provides abundant active sites and conductive medium to facilitate the ion/electron transmission,as well as ensure the GQDs@ZnxMnO_(2)composite cathode with enhanced charge-transfer capability and high electrochemical reversibility,which are elucidated by experiment results and in-situ Raman investigation.These impressive properties endow the GQDs@ZnxMnO_(2)composite cathode with superior aqueous Zn^(2+) storage capacity(~403.6 mAh·g^(−1)),excellent electrochemical kinetics,and good structural stability.For actual applications,the fabricated aqueous ZIBs can deliver a substantial energy density(226.8 W·h·kg^(−1)),a remarkable power density(650 W·kg^(−1)),and long-term cycle performance,further stimulating their potential application as efficient electrochemical storage devices for various energy-related fields.

Revealing the effect of electrolyte coordination structures on the intercalation chemistry of batteries

In-depth understanding of the electrolyte-dependent intercalation chemistry in batteries through direct operando/in situ characterizations is crucial for the development of the high-performance batteries.Herein,taking the Al/graphite battery as a model system,the effect of electrolyte coordination structure on the intercalation processes has been investigated over the batteries with either 1-hexyl-3-methylimidazolium chloride(HMICl)-AlCl_(3) or 1-ethyl-3-methylimidazolium chloride(EMICl)-AlCl_(3) ionic liquid electrolyte using operando X-ray photoelectron spectroscopy(XPS)and X-ray diffraction.With a weaker anion-cation interaction in HMI-based electrolyte,the XPS-derived atomic ratio between cointercalated N and intercalated Al is 0.9,which is lower than 1.6 for EMI-based electrolyte.Attributed to the additional de-solvation process,the batteries with the HMI-based electrolyte show a lower ionic diffusion rate,capacity,and cycling performance,which agree with the operando characterization results.Our findings highlight the critical role of the electrolyte coordination structure on the(co-)intercalation chemistry.

Er intercalation and its impact on transport properties of epitaxial graphene

Intercalation of atomic species is a practicable method for epitaxial graphene to adjust the electronic band structure and to tune the coupling between graphene and Si C substrate. In this work, atomically flat epitaxial graphene is prepared on 4H-SiC(0001) using the flash heating method in an ultrahigh vacuum system. Scanning tunneling microscopy, Raman spectroscopy and electrical transport measurements are utilized to investigate surface morphological structures and transport properties of pristine and Er-intercalated epitaxial graphene. It is found that Er atoms are intercalated underneath the graphene layer after annealing at 900℃, and the intercalation sites of Er atoms are located mainly at the bufferlayer/monolayer-graphene interface in monolayer domains. We also report the different behaviors of Er intercalation in monolayer and bilayer regions, and the experimental results show that the diffusion barrier for Er intercalated atoms in the buffer-layer/monolayer interface is at least 0.2 eV higher than that in the first/second graphene-layer interface. The appearance of Er atoms is found to have distinct impacts on the electronic transports of epitaxial graphene on SiC(0001).

Intercalation Assembly Method and Intercalation Process Control of Layered Intercalated Functional Materials

Layered intercalated functional materials of layered double hydroxide type are an important class of functional materials developed in recent years. Based on long term studies on these materials in the State Key Laboratory of Chemical Resource Engineering in Beijing University of Chemical Technology, the principle for the design of controlled intercalation processes in the light of future production processing requirements has been developed. Intercalation assembly methods and technologies have been invented to control the intercalation process for preparing layered intercalated materials with various structures and functions.

Intercalation Assembly and Chemical Product Engineering of Layered Intercalated Functional Materials Based on Efficient Utilization of Magnesium Resources in Salt Lakes

1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment

Doping inhomogeneity and staging of ultra-thin graphite intercalation compound flakes probed by visible and near-infrared Raman spectroscopy

When ultra-thin graphite intercalation compounds（GICs） are deposited on the SiO2/Si substrate, it is found that their colors are dependent on the thickness of GIC flakes. The sample colors of ultrathin GIC flakes can no longer provide qualitative information on the stage index. Here, multi-wavelength Raman spectroscopy is thus applied to study the doping inhomogeneity and staging of ultra-thin GICs by FeCl3 intercalation. The G band intensity of stage-1 GIC flakes is strongly enhanced by 532-nm laser excitation, while that of stage-2 and stage-3 flakes exhibits strong intensity enhancement for 785-nm laser excitation. The near-infrared lasers are suggested to probe the doping inhomogeneity and staging of ultra-thin GIC flakes.

Preparation and Properties of Phenolic Resin/Montmorillonite Intercalation Nanocomposites

Phenolic resin/montmorillonite intercalation composites were prepared by using the methods of pressing intercalation and melt intercalation.Properties and structure of the composites were investigated by using XRD,TG and test of softening point.It is indicated that both the pressing intercalation and melt intercalation can be used to prepare the phenolic resin/organo-montmorillonite intercalation nanocomposites.Compared with phenolic resin,the intercalation nanocomposites have better heat-resistance,higher decomposition temperatures and less thermal weight-loss.However,these two intercalation methods have different effects on the softening point of the intercalation nanocomposites.Pressing intercalation almost does not affect the softening point of the intercalation nanocomposites,while melt intercalation significantly increases the softening point of the intercalation nanocomposites, probably due to the chemical actions happening in the process of melt intercalation.

Lithium intercalation/de-intercalation behavior of a composite Sn/C thin film fabricated by magnetron sputtering

A tin film of 320 nm in thickness on Cu foil and its composite film with graphite of-50 nm in thickness on it were fabricated by magnetron sputtering. The surface morphology, composition, surface distributions of alloy elements, and lithium intercalation/de-intercalation behaviors of the fabricated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, electron probe microanalyzer （EPMA）, X-ray photoelectron spectroscopy （XPS）, inductively coupled plasma atomic emission spectrometry （ICP）, cyclic voltammetry （CV）, and galvanostatic charge/discharge （GC） measurements. It is found that the lithium intercalation/de-intercalation behavior of the Sn film can be significantly improved by its composite with graphite. With cycling, the discharge capacity of the Sn film without composite changes from 570 mAh/g of the 2nd cycle to 270 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 90% and 95%. Nevertheless, the discharge capacity of the composite Sn/C film changes from 575 mAh/g of the 2nd cycle to 515 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 95% and 100%. The performance improvement of tin by its composite with graphite is ascribed to the retardation of the bulk tin cracking from volume change during lithium intercalation and de-intercalation, which leads to the pulverization of tin.

Influence of blasting on the properties of weak intercalation of a layered rock slope

A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered rock slope. On the basis of in-situ stratification-cracking blasting tests, the properties of weak intercalation were investigated using the LS-DYNA3D program. The displacement distribution and compactness of weak intercalation at different positions away from the charge center and their various laws are discussed. The critical displacement of stratification-cracking （0.1 mm） was obtained, and an approximate expression of compactness were deduced. Furthermore, through the simulation of a layered rock blasting under the same geological conditions, the stratification-cracking effect of deep-hole blasting on the properties of weak intercalation was compared with that of short-hole blasting, and the influencing differences, in addition to their causes, were analyzed. The results indicated that the blasting cavity of weak intercalation in short-hole blasting with a radius of 40 mm was nearly a circle, whose radius was about 28.7 cm; whereas in deep-hole blasting with a radius of 150 mm, the shape of the blasting cavity was different from that in short-hole blasting, the radius of the cavity behind the charge （89.1 cm） was further smaller than those of the other three （138.7 cm）, and there were sharp crinkles on the surface of weak intercalation. When the distance from the charge center （DCC） was less than 40 and 150 cm in short-hole and deep-hole blasting, respectively, the displacement of weak intercalation was reduced remarkably with the increase in DCC.

Preparation and Structural Investigation of CuCl_2 Graphite Intercalation Compounds

Superfine graphite powder was prepared by ball-milling exfoliated graphite containing anhydrous CuCl2 in planetary ball milling systems. Nano-scale CuCl2 graphite intercalation compounds were synthesized by heating a mixture of anhydrous CuCl2 and graphite nanosheets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy were performed to characterize the microstructures of stage-1 nano-scale CuCl2 graphite intercalation compounds. The structure and components of the domain wall and core in the nano-scale CuCl2 graphite intercalation compounds are described. The results show that the content of CuCl2 in the mixture plays a crucial role in the size of the nano-scale CuCl2 graphite intercalation compound.

Melting Intercalation Method to Prepare Lauric Acid/Organophilic Montmorillonite Shape-stabilized Phase Change Material

A kind of novel shape-stabilized phase change material （SSPCM） was prepared by using a melting intercalation technique. This kind of SSPCM was made of lauric acid （LA） as a phase change material and organophilic montmorillonite （OMMT） as a support material. And the thermal properties and morphology of the SSPCM were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM）, scanning electronic microscope （SEM）, scanning calorimeter （DSC）, and differential thermal cravimetry （TG）. The DSC result shows that the phase change temperature of the SSPCM is close to that of LA, and its latent heat is equivalent to that of the calculated value based on the mass ratio of LA measured by TG. The XRD, SEM and TEM results demonstrate that the LA intercalates into the silicate layers of the OMMT, thus forming a typically intercalted hybrid, which can restrict the molecular chain of the LA within the structure of OMMT at high temperature. And consequently SSPCM can keep its solid state during its solid-liquid phase change processing.

Intercalation Assembly, Characterization and Luminescent Properties of Novel Supramolecular Composite Materials, Tb(Ⅲ) Complex with Tetrapodal Ligand-Montmorillonite

Two kinds of Tb（ Ⅲ ） complexes with tetrapodal ligand, [TbL（NO3）]^3＋ and [TbL]^3＋ （L： 1,1, 1＇, 1＇-tera （ 2-pyridinecarboxylester ）-di （ trimethylpropane）） were intercalated into the interlayer space of montmorillonite （MT） by ion exchange and coordination reaction of L with the Tb^3＋ ion existing in the interlayer space of Tb-MT respectively. The obtained luminescent supramolecular composite materials, [ TbL （NO3） ]^2＋-MT and [TbL]^3＋-MT were characterized by elemental analysis, XRD, FT-IR, UV-vis and thermal analysis. At the same time, the luminescent properties of the materials were also studied. The results show that the intercalated materials with regular layered structure, good thermal stability and the interlayer spacing （d001） approximates to the size of the complex ions which are located in the interlayer space of MT in the form of a monolayer.

Preparation and Photochemical Behavior of a Cationic Azobenzene Dye-Montmorillonite Intercalation Compound

Montmorillonite/cationic azobenzene dye（p-（δ-triethylammoniobutoxy）-p＇-methyl- azobenzene bromide） intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure cationic azo-dye, the thermal stability of the intercalated dye was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated dye shifted towards longer wave length by 38 nm. This could be ascribed to the strong conjugation of cationic azo-dye supramolecular order structure（J cluster） confined in a nanoscale space of montmorillonite interlayer gallery. UV/vis spectra data show that the intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and daylight cis-to-trans back reaction. FTIR indicates the successful intercalation of cationic azo-dye into the montmorillonite interlayer.

Metal porphyrin intercalated reduced graphene oxide nanocomposite utilized for electrocatalytic oxygen reduction

In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.