Reshaping Li–Mg hybrid batteries:Epitaxial electrodeposition and spatial confinement on MgMOF substrates via the lattice‐matching strategy

The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical integration.Herein,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF substrate.The chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial electrocrystallization.Moreover,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular scale.Taking inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF cavities.This innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical kinetics.The resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling performance.Surprisingly,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm^(–2)),maintaining operation for an extended 1200 h,surpassing previously reported benchmarks.Significantly,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallization driven by metal–organic framework(MOF)substrates,paving the way toward the advancement of cuttingedge batteries.

Oriented assembly of metal-organic frameworks and deficient TiO_(2) nanowires directed by lattice matching for efficient photoreversible color switching

The photoreversible color switching system(PCSS)is attracting increasing attention for use in alleviating energy crisis and environmental problems.We report a robust PCSS in which lattice matching enables bottom-up oriented assembly between metal-organic frameworks(MOFs)and inorganic nanocrystals(INCs),two distinct entities that differ drastically in structure and function.Specifically,cubic-phase Prussian blue(PB)of a framework backbone is spontaneously attached to rutile TiO_(2)nanowires in a defined orientation triggered by the lattice matching between the(001)plane of TiO_(2)and the(222)plane of PB.Ultraviolet light irradiation accelerates the photoelectron transport within the oriented TiO_(2)/PB system and enables fast photo switching.The derived TiO_(2)/PB paper can be ranked as one of the best light-printing papers in literature because of its high resolution(∼µm)and capability to be repeatedly written for>100 times without significant loss of contrast.The ultrathin TiO_(2)nanowires are rich in oxygen and Ti vacancies,which allow visible-and sunlight-light printing.Density functional theory calculations suggest that the[Fe(CN)_(6)]^(4−) ligand from the PB attaches preferentially to the(110)surface of TiO_(2)to give the ordered TiO_(2)/PB assembly.The findings demonstrate the strong versatility of particles-mediated assembly in advanced materials design.

Steering spatially separated dual sites on nano-TiO_(2)through SMSI and lattice matching for robust photocatalytic hydrogen evolution

Spatial isolation of different functional sites at the nanoscale in multifunctional catalysts for steering reaction sequence and paths remains a major challenge.Herein,we reported the spatial separation of dual-site Au and RuO_(2)on the nanosurface of TiO_(2)(Au/TiO_(2)/RuO_(2))through the strong metal-support interaction(SMSI)and the lattice matching(LM)for robust photocatalytic hydrogen evolution.The SMSI between Au and TiO_(2)induced the encapsulation of Au nanoparticles by an impermeable TiO_(x)overlayer,which can function as a physical separation barrier to the permeation of the second precursor.The LM between RuO_(2)and rutile-TiO_(2)can increase the stability of RuO_(2)/TiO_(2)interface and thus prevent the aggregation of dual-site Au and RuO_(2)in the calcination process of removing TiO_(x)overlayer of Au.The photocatalytic hydrogen production is used as a model reaction to evaluate the performance of spatially separated dual-site Au/TiO_(2)/RuO_(2)catalysts.The rate of hydrogen production of the Au/TiO_(2)/RuO_(2)is as high as 84μmol h^(−1)g^(−1)under solar light irradiation without sacrificial agents,which is 2.5 times higher than the reference Au/TiO_(2)and non-separated Au/RuO_(2)/TiO_(2)samples.Systematic characterizations verify that the spatially separated dual-site Au and RuO_(2)on the nanosurface of TiO_(2)can effectively separate the photo-generated carriers and lower the height of the Schottky barrier,respectively,under UV and visible light irradiation.This study provides new inspiration for the precise construction of different sites in multifunctional catalysts.

Different roles of surfaces’ interaction on lattice mismatched/matched surfaces in facilitating ice nucleation

The freezing of water is one of the most common processes in nature and affects many aspects of human activity. Ice nucleation is a crucial part of the freezing process and usually occurs on material surfaces. There is still a lack of clear physical pictures about the central question how various features of material surfaces affect their capability in facilitating ice nucleation. Via molecular dynamics simulations, here we show that the detailed features of surfaces, such as atomic arrangements, lattice parameters, hydrophobicity, and function forms of surfaces’ interaction to water molecules, generally affect the ice nucleation through the average adsorption energy per unit-area surfaces to individual water molecules, when the lattice of surfaces mismatches that of ice. However, for the surfaces whose lattice matches ice, even the detailed function form of the surfaces’ interaction to water molecules can largely regulate the icing ability of these surfaces. This study provides new insights into understanding the diverse relationship between various microscopic features of different material surfaces and their nucleation efficacy.

High Lattice Match Growth of InAsSb Based Materials by Molecular Beam Epitaxy

High lattice match growth of InAsSb based materials on GaSb substrates is demonstrated. The present results indicate that a stable substrate temperature and the optimal flux ratios are of critical importance in achieving a homogeneous InAsSb based material composition throughout the growth period. The quality of these epilayers is assessed using a high-resolution x-ray diffraction and atomic force microscope. The mismatch between the GaSb substrate and InAsSb alloy achieves almost zero, and the rms surface roughness of InAsSb alloy achieves around 1.7A over an area of 28μm × 28μm. At the same time, the mismatches between GaSb and InAs/InAs0.73Sb0.27 superlattices （SLs） achieve approximately 100 arcsec （75 periods） and zero （300 periods）, with the surface rms roughnesses of InAs/InAs0.73Sb0.27 SLs around 1.8 A （75 periods） and 2.1A （300 periods） over an area of 20 μm×20 μm, respectively. After fabrication and characterization of the devices, the dynamic resistance of the n-barrier-n InAsSb photodetector near zero bias is of the order of 10^6Ω·cm^2. At 77K, the positive-intrinsic-negative photodetectors are demonstrated in InAsSb and InAs/InAsSb SL （75 periods） materials, exhibiting fifty-percent cutoff wavelengths of 3.8μm and 5.1μm, respectively.

Room-Temperature Annealing of 1 MeV Electron Irradiated Lattice Matched In0.53Ga0.47As/InP Multiple Quantum Wells

Long-term room-temperature annealing effects of InGaAs/InP quantum wells with different wells （namely triple wells and five wells embedded） and bulk InCaAs are investigated after high energy electron irradiation. It is observed that the photoluminescence （PL） intensity of bulk InGaAs materials is enhanced after low dose electron irradiation and the PL intensity for all the three samples is degraded dramatically when the electron dose is relatively high. With respect to the room-temperature annealing, we find that the PL intensity for both samples recovers relatively fast at the initial stage. The PL performance of multiple quantum-well samples shows better recovery after irradiation compared with the results of bulk InGaAs materials. Meanwhile, the recovery speed factors of multiple quantum-well samples are relatively faster than those of the bulk InGaAs materials as well. We infer that the recovery difference between the quantum-well materials and bulk materials originates from the fact that the radiation induced defects are confined in the quantum wells as a consequence of the free energy barrier between the In0.53Ga0.47 As wells and InP barrier layers.

Li_(2)TiO_(3) Dopant and Phosphate Coating Improve the Electrochemical Performance of LiCoO2 at 3.0-4.6 V

A sol-gel tandem with a solid-phase modification procedure was developed to synthesize Li_(2)TiO_(3)-doped LiCoO_(2) together with phosphate coatings(denoted as LCO-Ti/P),which possesses excellent high-voltage performance in the range of 3.0-4.6 V.The characterizations of X-ray diffraction,high-resolution transmission electron microscopy,and X-ray photoelectron spectroscopy illustrated that the modified sample LCO-Ti/P had the dopant of monoclinic Li_(2)TiO_(3) and amorphous Li3PO4 coating layers.LCO-Ti/P has an initial discharge capacity of 211.6 mAh/g at 0.1 C and a retention of 85.7%after 100 cycles at 1 C and 25±1°C between 3.0 and 4.6 V.Nyquist plots reflect that the charge transfer resistance of LCO-Ti/P after 100 cycles at 1 C is much lower than that of the spent LCO,which benefits Li-ion diffusion.Density functional theory calculations disclose the superior lattice-matching property of major crystal planes for Li_(2)TiO_(3) and LiCoO_(2),the lower energy barriers for Li-ion diffusion in Li_(2)TiO_(3),and the suppressed oxygen release performance resulting from phosphate adsorption.This work provides useful guidance on the rational design of the high-voltage performance of modified LiCoO_(2) materials in terms of lattice-matching properties aside from the phosphate coating to reduce the energy barriers of Li-ion diffusion and enhance cycling stability.

Investigation on interface of NiFeCr/NiFe/Ta films with high magnetic field sensitivity

NiFeCr/NiFe/Ta films with excellent performance were prepared by magnetron sputtering system.The anisotropic magetoresistance (AMR) value (ΔR/R) and magnetic filed sensitivity (Sv,Sv=[d(ΔR/R)/dH]max.) for the 12 nm NiFe film deposited on NiFeCr buffer layer were 3.66% and 1.42×10-4%·T-1,respectively.The higher Sv of the film is close to that of a spin valve (SV).The microstructure analysis shows that the NiFeCr buffer layer has adopted the same structure with the same interplanar distance as the NiFe layer,inducing a strong NiFe (111) texture,and that the NiFeCr/NiFe interface is quite smooth,leading to a high degree of specular reflection of conduction electrons.Both increase the ΔR and reduce the R in the film,which lead to the high ΔR/R.Clean substrate surfaces are critical for preparation of high performance NiFeCr/NiFe/Ta films,and sputter cleaning or pre-deposition of 5 nm amorphous Al2O3 layer in the deposition chamber can provide the re-quired clean substrate surfaces for the growth of the buffer layer.

Catalytic combustion of methane over Pd/SnO_2 catalysts

SnO2‐supported Pd catalysts were prepared and the effects of the support calcination temperature on the subsequent catalytic activity during methane combustion were investigated.The physicochemical properties of the Pd/SnO2were characterized by X‐ray diffraction,high‐resolution transmission electron microscopy,X‐ray photoelectron spectroscopy,oxygen temperature‐programmed desorption and CH4temperature‐programmed surface reaction.Only crystalline Pd species were found on the catalysts fabricated from the supports calcined above800°C.It was also determined that lattice geometry matching between PdO and SnO2in the catalyst made with a support calcined at1200°C facilitated oxygen activation from SnO2to vacant oxygen sites on the PdO/Pd surface via the back‐spillover of oxygen.This effect in turn enhanced the catalytic combustion process.The activity of this material was clearly increased compared with the catalysts that did not exhibit lattice matching between the PdO and support.

Discrepancy of the magnetic behaviors and crystalline structure on the Co/FeMn and FeMn/Co interfaces with ultrathin Pt spacer

The exchange coupling at the ferromagnetic/antiferromagnetic （FM/AFM） interface is influenced by both the magnetic structure and the crystalline micro-structure. Co/FeMn/Co thin films with 0.4 nm Pt spacer layer inserted into the Co/FeMn and FeMn/Co interface respectively were deposited by means of magnetron sputtering. The two interfaces upon and beneath the FeMn layer show distinct behaviors before and after the Pt spacer inserted. There is a remarkable shrink of the interracial uncompensated spins within the FeMn bottom interracial monolayers, whereas a relaxation of the pinning strength of the FeMn interfacial spins along the out-of-plane direction occurs at the top in- terface. XRD analysis indicates the Pt layer upon the FeMn layer forms an fcc （002） texture, implying the magnetic discrepancy between the top and bottom FeMn interfaces has crystalline structural origins.

Effects and Mechanism of Titanium Modification on Structures of Cast Steel ZG270-500

The influences of titanium modification on the solidification behavior, shrinkage characteristic and primary austenite refinement of cast steel ZG270-500 smelted in intermediate frequency induction furnace were studied. 0.15wt% titanium modification increased the fluidity of the steel liquid, enhanced the feeding capacity of cast steel, changed the dispersed shrinkage porosity to concentrated shrinkage cavity, turned the coarse dendrites into fine equiaxed grain structures and greatly reduced the primary austenite grain size. By scanning electron microscope （SEM） and energy disperse spectroscope （EDS） analysis, it was found that titanium combined with carbon to be solid phase particles TiC, with high melting point, to promote the primary austenite nucleation authentically by non-spontaneous nucleating. The crystal lattice match growing model between γ–Fe and TiC was established. The mechanism of TiC heterogeneous nucleating existed in that the primary austenite grew up by {111}γ-Fe parallel to the closest packed plane {111}TiC in the crystal orientation 110γ-Fe//211TiC. The crystal planes mismatch and the lowest orientation mismatchδ110γ-Fe 110TiC were 8.18%. and 2.25% respectively, almost achieving complete coherent lattice match growing of austenite on TiC.

Interface characteristics between TiN and matrix and their effect on solidification structure

Heterogeneous nucleation is an effective way to promote the dispersion and precipitation of second-phase particles in steel and refine the grain size of the solidification structure.Not only refining as-cast structure grain size,but TiN in ferritic stainless steel can also pin grain boundaries and restrain the overgrowth of grains during rolling.The interface characteristics between TiN and heterogeneous phases(high-melting inclusions and ferrite phase)were studied based on the wetting angles between molten steel with different compositions and TiN substrate,and on the matching degree between TiN and ferrite lattice.It was found that,for the molten steel with the same composition,the wetting angle with the TiN substrate was significantly smaller than the contact angles with the other three substrates,while the wetting angle between ferrite phase and TiN was the smallest.The lattice matching was compared among MgAl_(2)O_(4),TiN andδmatrix by means of a high-resolution transmission electron microscope,which revealed that a coherent or semi-coherent interface was formed between the crystal plane(400)of MgAl_(2)O_(4)and the crystal plane(200)of TiN,as well as between the crystal plane(200)of TiN and the crystal plane(110)ofδmatrix,with a lattice misfit of 5.1%and 3.4%,respectively.Finally,these two characteristics between TiN and ferrite phase were both explained from the perspective of interfacial energy.The microstructure refinement mechanism from high temperature to room temperature can be better reflected by the proposed wetting–lattice misfit theory.

Precise synthesis of multilevel branched organic microwires for optical signal processing in the near infrared region

Complicated multilevel micro/nanostructures have attracted great attention as essential basic components of integrated optoelectronic devices.However,precise synthesis of these well-designed micro/nanostructures is still a major challenge.In this report,a series of near-infrared emissive multilevel branched organic microwires with different integrated levels are successfully fabricated for the first time by a facile self-assembly approach based on our well designed and synthesized(2E,2′E)-1,1′-(1,5-dihydroxynaphthalene-2,6-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one)(DHNBP).The growth mechanism is attributed to lattice matching between(100)and(010)crystal planes,with an interplanar spacing mismatch rate as low as 5.3%.Benefiting from the uniaxial oriented molecular packing mode of the crystal,the well-prepared microwires have outstanding optical properties.More significantly,the branched structures can work as optical logic gates and optical signal processors.Therefore,this synthesis method for multilevel branched microwires will potentially facilitate the development of organic integrated optoelectronics.

Block-layer model for intergrowth structures

Lattice match and charge transfer between distinct block layers(BLs)play an important role in the formation of an intergrowth structure.Herein we propose a simple BL model addressing the different roles of the lattice match and the charge transfer.Inter-BL charge transfer lowers the internal energy,while lattice match minimizes the elastic energy,both of which together make the intergrowth structure stabilized.The model is able to reproduce the lattice parameters precisely for complex iron-based superconductors with intergrowth structures.The elastic energy and the charge-transfer energy are evaluated with assistance of the first-principles calculations.This work rationalizes the basic principles of BL design for intergrowth structures,which can be utilized not only for finding new superconducting materials but also for investigating other layered materials with various functionalities.

The X-ray diffraction study of epitaxial La_(0.67)Sr_(0.33)MnO_(3）single crystal thin film

THE colossal magnetoresistance (CMR) effects in doped perovskite-like oxide have stimulatedconsiderable attention to the study of fundamental physics and the application of new type ma-terials. It was reported that a large CMR effect and a high critical temperature T_c shown