Developing high-performance Ni cathodes and understanding the relationship between electron states of Ni 3d orbital and energy storage mechanism from an atomic-orbital perspective are crucial yet challenging for alkal...Developing high-performance Ni cathodes and understanding the relationship between electron states of Ni 3d orbital and energy storage mechanism from an atomic-orbital perspective are crucial yet challenging for alkaline nickel-zinc batteries.Herein,we innovatively design P-NiMoO_(4)/NiSe_(2)heterostructures with rich oxygen vacancy via a selective component segregation.The P substitution in NiMoO_(4)activate Ni atoms,leading to the spin-state transition of Ni-3d orbitals from high-spin to low-spin,which promote the uniform and rapid nucleation of NiSe_(2)on the surface of NiMoO_(4)during subsequent selenization process.After selenization,the in situ formed P-NiMoO_(4)/NiSe_(2)heterostructures exhibits continuous increased unoccupied states of Ni 3d-orbitals and higher Ni valence state.The synergistic effect of P doping and selenization modulate the d-band center(ɛd)level of Ni 3d,thereby promoting d-p orbital hybridization between Ni 3d and O 2p of OH−as well as OH−adsorption ability.Consequently,the P-NiMoO_(4)/NiSe_(2)exhibits a top-level specific capacity of 390.7 mA h g^(−1)at 1 A g^(−1),2.8-fold higher than that of pristine NiMoO_(4),accompanied by remarkable rate capability and structural stability.Moreover,the assembled pouch-type battery and flexible devices demonstrate the practical application potential.This work provides fundamental insights into orbital-level engineering of battery materials for enhanced redox kinetics and cycling stability.展开更多
Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study el...Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study elucidates the fundamental mechanisms of ultrafast laser shock imprinting(LSI)in two-dimensional tellurium(Te),establishing a direct relationship between strain field orientation,mold topology,and anisotropic structural evolution.This is the first demonstration of ultrafast LSI on chiral chain Te unveiling orientation-sensitive dislocation networks.By applying controlled strain fields parallel or transverse to Te’s helical chains,we uncover two distinct deformation regimes.Strain aligned parallel to the chain’s direction induces gliding and rotation governed by weak interchain interactions,preserving covalent intrachain bonds and vibrational modes.In contrast,transverse strain drives shear-mediated multimodal deformations—tensile stretching,compression,and bending—resulting in significant lattice distortions and electronic property modulation.We discovered the critical role of mold topology on deformation:sharp-edged gratings generate localized shear forces surpassing those from homogeneous strain fields via smooth CD molds,triggering dislocation tangle formation,lattice reorientation,and inhomogeneous plastic deformation.Asymmetrical strain configurations enable localized structural transformations while retaining single-crystal integrity in adjacent regions—a balance essential for functional device integration.These insights position LSI as a precision tool for nanoscale strain engineering,capable of sculpting 2D material morphologies without compromising crystallinity.By bridging ultrafast mechanics with chiral chain material science,this work advances the design of strain-tunable devices for next-generation electronics and optoelectronics,while establishing a universal framework for manipulating anisotropic 2D systems under extreme strain rates.This work discovered crystallographic orientation-dependent deformation mechanisms in 2D Te,linking parallel strain to chain gliding and transverse strain to shear-driven multimodal distortion.It demonstrates mold geometry as a critical lever for strain localization and dislocation dynamics,with sharp-edged gratings enabling unprecedented control over lattice reorientation.Crucially,the identification of strain field conditions that reconcile severe plastic deformation with single-crystal retention offers a pathway to functional nanostructure fabrication,redefining LSI’s potential in ultrafast strain engineering of chiral chain materials.展开更多
Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with ...Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with a unique molecular structure,camphorsulfonic acid(CSA),is first proposed to remodel the interface microenvironment as an electrolyte additive.The proton provided by CSA can neutralize the hydroxide ions generated by side reactions and inhibit the accumulation of alkaline by-products.The sulfonic acid groups are firmly adsorbed on the Zn anode surface,thereby enabling the regulation of interfacial species.Specifically,oxygen-containing functional groups combined with hydrophobic rigid carbon rings achieve a water-poor interface environment and promote the transfer of Zn^(2+),providing a suitable environment for Zn deposition.As a result,Zn//Zn symmetrical battery can run for over 2800 h(2 mA cm^(-2)-2 mAh cm^(-2)),demonstrating 28-times lifespan compared to the battery without CSA.Furthermore,Zn//KVO full cell presents excellent performance of 800 cycles at 3 A g^(-1).Besides,the pouch cell with CSA can also operate a capacity of 153.8 mAh after 60 cycles at 0.5 A g^(-1) with96.5%capacity retention rate.This work provides an organism-inspired additive selection for stabilizing the interface chemistry of the Zn anode.展开更多
Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,whic...Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,which are energy-intensive and prone to secondary pollution,the direct regeneration approach has emerged as a rapid and highly efficient method,gaining widespread attention in recent years.However,this approach faces major challenges,including degraded electrochemical performances and limited economic value.This study,therefore,proposes a high-value direct regeneration strategy to convert degraded spent LiFePO_(4)(S-LFP)into a gradient manganese(Mn)-doped regenerated LiFe_(0.7)Mn_(0.3)PO_(4)/C(R-LFMP)composite.This method leverages the inherent microcracks and Li vacancies present in S-LFP,likely acting as diffusion channels for the Mn^(2+)/Li^(+)ions.Through a two-step mechanochemical ball-milling and carbothermal reduction process,this approach achieves simultaneous Li replenishment and surface-localised Mn gradient doping with enhanced structural control.Notably,the R-LFMP exhibits an exceptional electrochemical performance.At 0.1 C,it delivers a discharge capacity of 161.4 mA h g^(−1)and an energy density of 563.5 Wh kg^(−1)(representing a 60.5%improvement over S-LFP).Additionally,it maintains 83%capacity retention after 900 cycles at 0.5C,a considerable enhancement compared to commercial LFMP(62%).Furthermore,the regenerated cathode material generates a net profit of$7.102 kg^(−1),surpassing the profitability of conventional recycling methods by 90%.Overall,this study introduces a transformative and sustainable LFP regeneration technology,achieving breakthroughs in electrochemical restoration and high-value recycling,while paving the way for the closed-loop utilisation of LFP-based energy storage systems.展开更多
The sulfide fusion method was used to synthesize Gd_2 O_2 S:Tb phosphors using commercial Gd_2 O_3 and freshly prepared Gd_2 O_3, respectively. The freshly prepared Gd_2 O_3 was synthesized from Gd_2 O(GO_3)_2·H_...The sulfide fusion method was used to synthesize Gd_2 O_2 S:Tb phosphors using commercial Gd_2 O_3 and freshly prepared Gd_2 O_3, respectively. The freshly prepared Gd_2 O_3 was synthesized from Gd_2 O(GO_3)_2·H_2 O precursor prepared by homogeneous precipitation method.The structure and morphology of the composites were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The result shows that the Gd_2 O_2 S:Tb phosphor prepared by commercial Gd2 O3(GOST-A) presents agglomerated particles with average particle size of2.1 μm; however, Gd_2 O_2 S:Tb produced from as-prepared Gd_2 O_3(GOST-B) tends to form regular hexagon particles with the average particle size of 1 μm. Furthermore, Gd3+and Tb3+ contents in GOST-B are higher than that in GOST-A. In addition, fluorescent properties were analyzed by fluorescent spectrophotometer. It is indicated that similar excitation and emission spectra can be obtained from the two phosphors, but the luminescence intensity of GOST-B is higher than that of GOST-A.展开更多
The preparation of cementitious materials by replacing part of the cement with activated coal gangue is of great significance to the cement industry in terms of carbon reduction and coal-based solid waste utilization....The preparation of cementitious materials by replacing part of the cement with activated coal gangue is of great significance to the cement industry in terms of carbon reduction and coal-based solid waste utilization.For this paper,cementitious material was prepared by firing activated coal gangue under suspension conditions and batching it with limestone powder using Inner Mongolia coal gangue as raw material.The optimal ratio was determined by testing the strength changes of the cementitious material at 3,7,and 28 days of hydration,and the hydration process and mechanism were explored by combining the pore structure,heat of hydration,chemical composition,phase composition,and microscopic morphological characteristics of the hydration products.The results showed that the active materials formulated from activated gangue and limestone powder can be used to prepare cementitious materials with good performance at the level of 30%–50%replacement of cement.The optimal ratio was 30%replacement of cement,and the mass ratio of calcined gangue to limestone powder was 2:1.The 3 days compressive strength of this ratio was 28.8 MPa,which was only slightly lower than that of cement.However,the 28 days compressive strength of samples reached 67.5 MPa,which was much higher than that of the reference cement.In the hydration of this cementitious material,not only does the activated coal gangue react with the Ca(OH)_(2)formed by hydration to form C–S–H gel,but CaCO3 also participates in the reaction to form a new phase of carbon aluminate,and the two effects together promote the development of the later strength of the samples.This paper can provide a reference for carbon reduction in the cement production process and comprehensive utilization of coal gangue.展开更多
Zirconia/stainless steel (ZrO2/SUS316L) functionally graded materials (FGMs) were fabricated by tape casting and laminating. Microstructures of FGMs were observed by optical microscope. Fracture behavior of FGMs in di...Zirconia/stainless steel (ZrO2/SUS316L) functionally graded materials (FGMs) were fabricated by tape casting and laminating. Microstructures of FGMs were observed by optical microscope. Fracture behavior of FGMs in different loading modes and influences of different gradient changes on flexural strength were investigated. The results show that ZrO2/ SUS316L FGMs with graded components at interlayers are obtained after they are sintered in vacuum and pressureless condition at 1 350 ℃. TheⅠ?Ⅱ mixed mode crack creates in composite layer and grows to both sides zigzag while loading on ZrO2 layer. Flexural strengths are 496.4,421.7 and 387.5 MPa when gradient changes are 10%,15% and 20%,but flexural strengths of the corresponding fracture layers are 387.1,334.6 and 282.3 MPa since cracks of FGMs are affected by three-dimensional stress,respectively. The cracks are generated in ZrO2 layer and extend to SUS316L layer while loading is added on SUS316L layer,flexural strength does not change with the graded components and keeps consistent basically.展开更多
Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide（CTAB）as template.The effect of several factors on surface a...Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide（CTAB）as template.The effect of several factors on surface area of products also had been discussed.The products were characterized by FT- IR,HRTEM and N 2 adsorption and desorption isotherm plot methods.There was typical structure as Si-O,Si- OH and Si-O-Si of mesoporous materials in the framework of synthesized materials;the pore size distributions of the products showed a sharp peak at 3.82 nm.The effect of hydrothermal treatment time and the amount of template on the specific surface area of mesoporous materials was important,when the Surf/Si=0.135,and hydrothermal time=12 h,and the surface area of the product reached up to 1 070 m2/g,which was higher than other products.展开更多
In this paper, the two-flume method was used to study the change laws of the thermal conductivity and thermal expansion coefficient of diamond/Cu composite materials with 100, 300, and 500 cycle numbers, under the act...In this paper, the two-flume method was used to study the change laws of the thermal conductivity and thermal expansion coefficient of diamond/Cu composite materials with 100, 300, and 500 cycle numbers, under the action of thermal shock load between-196 and 85 °C; the X-ray diffraction method（XRD） was used to study the change of the residual stress in the thermal shock process of the diamond/Cu composite materials; and the evolution of the fracture microstructure with different thermal shock cycle numbers was observed through scanning electron microscopy（SEM）. The results of the study show that the increase of the binder residue at the interface reduces the thermal shock stability of the diamond/Cu composite materials. In addition, under the thermal shock load between-196 and 85 °C, the residual stress of the diamond/Cu composite materials increases continuously with the increase of the cycle numbers, the increase of residual stress leads to a small amount of interface debonding, an increase of the interfacial thermal resistances, and a decrease of the constraints of low-expansion component on material deformation, thus the thermal conductivity decreases slightly and the thermal expansion coefficient increases slightly.展开更多
3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spec...3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.展开更多
Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this s...Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel P92.The TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 steel.The prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were investigated.Compared to the AR specimen,the PAG size did not change significantly.The fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction ratio.The PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR specimen.Moreover,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.展开更多
In this paper,the main research work and related reports of materials science research in China’s space technology field during 2020-2022 are summarized.This paper covers Materials Sciences in Space Environment,Mater...In this paper,the main research work and related reports of materials science research in China’s space technology field during 2020-2022 are summarized.This paper covers Materials Sciences in Space Environment,Materials Sciences for Space Environment,Materials Behavior in Space Environment and Space experimental hardware for material investigation.With the rapid development of China’s space industry,more scientists will be involved in materials science,space technology and earth science researches.In the future,a series of disciplines such as space science,machinery,artificial intelligence,digital twin and big data will be further integrated with materials science,and space materials will also usher in new development opportunities.展开更多
Deep coal-energy mining frequently results in microseismic(MS)events,which may be a precursor to the risk of rockbursts and pose risks to human safety and infrastructure.Therefore,quantitatively predicting the time,en...Deep coal-energy mining frequently results in microseismic(MS)events,which may be a precursor to the risk of rockbursts and pose risks to human safety and infrastructure.Therefore,quantitatively predicting the time,energy,and location(TEL)of future MS events is crucial for understanding and preventing potential catastrophic events.In this study,we introduced the application of spatiotemporal graph convolutional networks(STGCN)to predict the TEL of MS events induced by deep coal-energy mining.Notably,this was the first application of graph convolution networks(GCNs)in the spatiotemporal prediction of MS events.The adjacency matrices of the sensor networks were determined based on the distance between MS sensors,the sensor network graphs we constructed,and GCN was employed to extract the spatiotemporal details of the graphs.The model is simple and versatile.By testing the model with on-site MS monitoring data,our results demonstrated promising efficacy in predicting the TEL of MS events,with the cosine similarity(C)above 0.90 and the mean relative error(MRE)below 0.08.This is critical to improving the safety and operational efficiency of deep coal-energy mining.展开更多
Two new Mn(Ⅱ)coordination polymers,namely{[Mn_(2)(HL)(phen)_(3)(H_(2)O)_(2)]·7.5H_(2)O}_n(1)and[Mn_(4)(HL)_(2)(1,4-bib)_(3)(H_(2)O)_(2)]_n(2),were synthesized under hydrothermal conditions by using Mn(Ⅱ)ions an...Two new Mn(Ⅱ)coordination polymers,namely{[Mn_(2)(HL)(phen)_(3)(H_(2)O)_(2)]·7.5H_(2)O}_n(1)and[Mn_(4)(HL)_(2)(1,4-bib)_(3)(H_(2)O)_(2)]_n(2),were synthesized under hydrothermal conditions by using Mn(Ⅱ)ions and 6-(3',4'-dicarboxylphenoxy)-1,2,4-benzenetricarboxylic acid(H_(5)L)in the presence of N-auxiliary ligands 1,10-phenanthroline(phen)and1,4-bis(1H-imidazol-1-yl)benzene(1,4-bib).The structures of coordination polymers 1 and 2 were characterized by infrared spectroscopy,single-crystal X-ray diffraction,thermogravimetric analysis,and powder X-ray diffraction.Single-crystal X-ray diffraction reveals that 1 has a 1D chain structure based on binuclear Mn(Ⅱ)units,while 2 features a(3,8)-connected 3D network structure based on tetranuclear Mn(Ⅱ)units.Magnetic studies show that 1 and 2exhibit antiferromagnetic interactions between manganese ions.2 shows stronger antiferromagnetic interactions due to the shorter Mn…Mn distances within the tetranuclear manganese units.CCDC:2357601,1;2357602,2.展开更多
The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing gr...The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.展开更多
LiGe_(2_(PO_(4))3:Cr^(3+)near-infrared phosphor samples were prepared using high-temperature solid-state method and the corresponding PC-LED devices were prepared.Detailed research was conducted on the photoluminescen...LiGe_(2_(PO_(4))3:Cr^(3+)near-infrared phosphor samples were prepared using high-temperature solid-state method and the corresponding PC-LED devices were prepared.Detailed research was conducted on the photoluminescence characteristics of the samples and the performance of PC-LEDs.Under the excitation of 442 nm blue light,the phosphor obtained by calcination at 1000℃for 4 h exhibited an emission peak at 778 nm in the broadband near-infrared spectrum.The excitation peak of LiGe_(2_(PO_(4))3:Cr^(3+)underwent the energy level transitions,^(4)A_(2)(4F)→^(4)T_(1)(4P)and^(4)A_(2)(4F)→^(4)T_(1)(4F),while the emission peak underwent the energy level transition,^(4)T_(2)(4F)→^(4)A_(2)(4F).By coating the phosphor on the surface of the InGaN blue-light chip,The near-infrared PC-LED was prepared,and a near-infrared LED light source with broadband emission was obtained.At a driving current of 60 mA,the near-infrared light radiation power was 7 mW.The experimental results indicate that LiGe_(2_(PO_(4))3:Cr^(3+)near-infrared phosphor can be used to prepare broadband near-infrared LED light sources based on blue-light chips,which has intriguing applications in near-infrared spectroscopy.展开更多
As cathode materials for alkali-ion batteries,sodium manganese oxides have been receiving considerable and continuous attention in recent decades.In this work,the structure and environment-dependent stability of NaMn_...As cathode materials for alkali-ion batteries,sodium manganese oxides have been receiving considerable and continuous attention in recent decades.In this work,the structure and environment-dependent stability of NaMn_(2)O_(4) surface were studied based on the first principles calculations.The surface stability diagram of NaMn_(2)O_(4) involving various different terminations of(100),(110)and(111)surfaces was constructed,and the stability of these different terminations could be compared as a function of chemical environment.It is found that the(100)-MnO and(111)-ONa terminations are two more stable terminations under the investigated chemical conditions.And the surface energies of(110)surfaces are negative under the investigated chemical potential,hence,(110)surfaces are unstable.The surface energy of NaMn_(2)O_(4) as a function of O chemical potential is also investigated under constant Na chemical potential.The structure relaxation indicates that the surface rumpling and surface reconstruction can affect the electronic structure of the surface,thereby reducing surface energy and stabilizing the surface.Furthermore,the Wulff shape of NaMn_(2)O_(4) was also constructed based on Gibbs-Wulff theorem.展开更多
The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercala...The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercalation process,thereby affecting the cycling stability and lifespan of sodium-ion batteries(SIBs).In this work,a novel approach involving anionic doping and structural design has been proposed,wherein a two-step in-situ selenization and surface thermal annealing doping process is applied to fabricate a novel configuration material of fluorine-doped MoSe_(2)@nitrogen-doped carbon nanosheets(F-MoSe_(2)@FNC).The obtained F-MoSe_(2)@FNC,benefiting from the dual advantages of structure and F-doping,synergistically promotes and accelerates the stable(de)intercalation of Na^(+).Henceforth,F-MoSe_(2)@FNC demonstrates notable characteristics in terms of reversible specific capacity,boasting a high initial coulombic efficiency of 76.97%,alongside remarkable rate capabilities and cyclic stability.The constructed F-MoSe_(2)@FNC anode-based half cell manifests exceptional longevity,enduring up to 2550 cycles at 10 A·g^(-1)with a specific capacity of 322.04 mAh·g^(-1).Its electrochemical performance surpasses that of MoSe_(2)@NC and Pure MoSe_(2),underscoring the significance of the proposed synergistic modulation.Through comprehensive kinetic analyses,encompassing in-situ electrochemical impedance spectroscopy(EIS),it is elucidated that the F-MoSe_(2)@FNC electrode showcases elevated pseudo-capacitance and rapid diffusion attributes during charge and discharge processes.Furthermore,the assembled full-cell(F-MoSe_(2)@FNC//Na_(3)V_(2)(PO_(4))_(3))attains a notable energy density of 166.94 Wh·kg^(-1).This design provides insights for the optimization of MoSe_(2)electrodes and their applications in SIBs.展开更多
Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by in...Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by inherent structural instability and ambiguous structure-kinetics correlation.In this study,Fe NCN crystallites with selectively exposed(002)and{010}facets were precisely engineered and synthesized.Notably,the sodium storage kinetics and electrochemical performance of Fe NCN exhibit facet-dependent variations.Polyhedral-Fe NCN(P-Fe NCN)dominated by{010}facets exhibited a pseudocapacitance-driven storage mechanism and delivered exceptional rate capability(372 m Ah/g at5 A/g)and long cyclability(95.8%capacity retention after 300 cycles at 0.5 A/g).In contrast,sheet-like Fe NCN(S-Fe NCN)with predominant(002)facet exposure displayed diffusion-limited kinetics due to sluggish ion diffusion rate.Crucially,time-resolved operando XRD analysis and DFT simulation bridge this performance gap to mechanistic origins:Fe NCN as an intercalation-conversion type anode,the solid-state diffusion is the rate-determining step during charge/discharge process.Active{010}facets possess numerous broad hexagonal tunnels,coupled with a low diffusion barrier of 0.168 e V along{010}directions.This unique architectural configuration enables rapid sodium-ion transport,thereby shifting the diffusioncontrolled kinetics to intercalation-pseudocapacitive behavior.This discovery establishes active facet exposure as a storage kinetic switch,offering a generalized paradigm for optimizing the rate performance and stability of sodium-ion batteries.展开更多
Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon d...Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.展开更多
基金supported by the National Natural Science Foundation of China (Grant no. 22209083)
文摘Developing high-performance Ni cathodes and understanding the relationship between electron states of Ni 3d orbital and energy storage mechanism from an atomic-orbital perspective are crucial yet challenging for alkaline nickel-zinc batteries.Herein,we innovatively design P-NiMoO_(4)/NiSe_(2)heterostructures with rich oxygen vacancy via a selective component segregation.The P substitution in NiMoO_(4)activate Ni atoms,leading to the spin-state transition of Ni-3d orbitals from high-spin to low-spin,which promote the uniform and rapid nucleation of NiSe_(2)on the surface of NiMoO_(4)during subsequent selenization process.After selenization,the in situ formed P-NiMoO_(4)/NiSe_(2)heterostructures exhibits continuous increased unoccupied states of Ni 3d-orbitals and higher Ni valence state.The synergistic effect of P doping and selenization modulate the d-band center(ɛd)level of Ni 3d,thereby promoting d-p orbital hybridization between Ni 3d and O 2p of OH−as well as OH−adsorption ability.Consequently,the P-NiMoO_(4)/NiSe_(2)exhibits a top-level specific capacity of 390.7 mA h g^(−1)at 1 A g^(−1),2.8-fold higher than that of pristine NiMoO_(4),accompanied by remarkable rate capability and structural stability.Moreover,the assembled pouch-type battery and flexible devices demonstrate the practical application potential.This work provides fundamental insights into orbital-level engineering of battery materials for enhanced redox kinetics and cycling stability.
基金financial support from NSF ExpandQISE program.The synthesis of tellurene was supported by NSF under grant no.CMMI-2046936supports from Purdue Research Foundation.
文摘Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study elucidates the fundamental mechanisms of ultrafast laser shock imprinting(LSI)in two-dimensional tellurium(Te),establishing a direct relationship between strain field orientation,mold topology,and anisotropic structural evolution.This is the first demonstration of ultrafast LSI on chiral chain Te unveiling orientation-sensitive dislocation networks.By applying controlled strain fields parallel or transverse to Te’s helical chains,we uncover two distinct deformation regimes.Strain aligned parallel to the chain’s direction induces gliding and rotation governed by weak interchain interactions,preserving covalent intrachain bonds and vibrational modes.In contrast,transverse strain drives shear-mediated multimodal deformations—tensile stretching,compression,and bending—resulting in significant lattice distortions and electronic property modulation.We discovered the critical role of mold topology on deformation:sharp-edged gratings generate localized shear forces surpassing those from homogeneous strain fields via smooth CD molds,triggering dislocation tangle formation,lattice reorientation,and inhomogeneous plastic deformation.Asymmetrical strain configurations enable localized structural transformations while retaining single-crystal integrity in adjacent regions—a balance essential for functional device integration.These insights position LSI as a precision tool for nanoscale strain engineering,capable of sculpting 2D material morphologies without compromising crystallinity.By bridging ultrafast mechanics with chiral chain material science,this work advances the design of strain-tunable devices for next-generation electronics and optoelectronics,while establishing a universal framework for manipulating anisotropic 2D systems under extreme strain rates.This work discovered crystallographic orientation-dependent deformation mechanisms in 2D Te,linking parallel strain to chain gliding and transverse strain to shear-driven multimodal distortion.It demonstrates mold geometry as a critical lever for strain localization and dislocation dynamics,with sharp-edged gratings enabling unprecedented control over lattice reorientation.Crucially,the identification of strain field conditions that reconcile severe plastic deformation with single-crystal retention offers a pathway to functional nanostructure fabrication,redefining LSI’s potential in ultrafast strain engineering of chiral chain materials.
基金financially supported by The Excellent Youth Project of the Education Department of Hunan Province(No.24B0008)the National Natural Science Foundation of China(No.52377222)。
文摘Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with a unique molecular structure,camphorsulfonic acid(CSA),is first proposed to remodel the interface microenvironment as an electrolyte additive.The proton provided by CSA can neutralize the hydroxide ions generated by side reactions and inhibit the accumulation of alkaline by-products.The sulfonic acid groups are firmly adsorbed on the Zn anode surface,thereby enabling the regulation of interfacial species.Specifically,oxygen-containing functional groups combined with hydrophobic rigid carbon rings achieve a water-poor interface environment and promote the transfer of Zn^(2+),providing a suitable environment for Zn deposition.As a result,Zn//Zn symmetrical battery can run for over 2800 h(2 mA cm^(-2)-2 mAh cm^(-2)),demonstrating 28-times lifespan compared to the battery without CSA.Furthermore,Zn//KVO full cell presents excellent performance of 800 cycles at 3 A g^(-1).Besides,the pouch cell with CSA can also operate a capacity of 153.8 mAh after 60 cycles at 0.5 A g^(-1) with96.5%capacity retention rate.This work provides an organism-inspired additive selection for stabilizing the interface chemistry of the Zn anode.
基金supported by the National Key Research and Development Program of China(2023YFB3809300).
文摘Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,which are energy-intensive and prone to secondary pollution,the direct regeneration approach has emerged as a rapid and highly efficient method,gaining widespread attention in recent years.However,this approach faces major challenges,including degraded electrochemical performances and limited economic value.This study,therefore,proposes a high-value direct regeneration strategy to convert degraded spent LiFePO_(4)(S-LFP)into a gradient manganese(Mn)-doped regenerated LiFe_(0.7)Mn_(0.3)PO_(4)/C(R-LFMP)composite.This method leverages the inherent microcracks and Li vacancies present in S-LFP,likely acting as diffusion channels for the Mn^(2+)/Li^(+)ions.Through a two-step mechanochemical ball-milling and carbothermal reduction process,this approach achieves simultaneous Li replenishment and surface-localised Mn gradient doping with enhanced structural control.Notably,the R-LFMP exhibits an exceptional electrochemical performance.At 0.1 C,it delivers a discharge capacity of 161.4 mA h g^(−1)and an energy density of 563.5 Wh kg^(−1)(representing a 60.5%improvement over S-LFP).Additionally,it maintains 83%capacity retention after 900 cycles at 0.5C,a considerable enhancement compared to commercial LFMP(62%).Furthermore,the regenerated cathode material generates a net profit of$7.102 kg^(−1),surpassing the profitability of conventional recycling methods by 90%.Overall,this study introduces a transformative and sustainable LFP regeneration technology,achieving breakthroughs in electrochemical restoration and high-value recycling,while paving the way for the closed-loop utilisation of LFP-based energy storage systems.
基金financially supported by the National Natural Science Foundation of China (No. 51202111)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The sulfide fusion method was used to synthesize Gd_2 O_2 S:Tb phosphors using commercial Gd_2 O_3 and freshly prepared Gd_2 O_3, respectively. The freshly prepared Gd_2 O_3 was synthesized from Gd_2 O(GO_3)_2·H_2 O precursor prepared by homogeneous precipitation method.The structure and morphology of the composites were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The result shows that the Gd_2 O_2 S:Tb phosphor prepared by commercial Gd2 O3(GOST-A) presents agglomerated particles with average particle size of2.1 μm; however, Gd_2 O_2 S:Tb produced from as-prepared Gd_2 O_3(GOST-B) tends to form regular hexagon particles with the average particle size of 1 μm. Furthermore, Gd3+and Tb3+ contents in GOST-B are higher than that in GOST-A. In addition, fluorescent properties were analyzed by fluorescent spectrophotometer. It is indicated that similar excitation and emission spectra can be obtained from the two phosphors, but the luminescence intensity of GOST-B is higher than that of GOST-A.
基金funded by the National Natural Science Foundation of China Projects(Grant No.51672207).
文摘The preparation of cementitious materials by replacing part of the cement with activated coal gangue is of great significance to the cement industry in terms of carbon reduction and coal-based solid waste utilization.For this paper,cementitious material was prepared by firing activated coal gangue under suspension conditions and batching it with limestone powder using Inner Mongolia coal gangue as raw material.The optimal ratio was determined by testing the strength changes of the cementitious material at 3,7,and 28 days of hydration,and the hydration process and mechanism were explored by combining the pore structure,heat of hydration,chemical composition,phase composition,and microscopic morphological characteristics of the hydration products.The results showed that the active materials formulated from activated gangue and limestone powder can be used to prepare cementitious materials with good performance at the level of 30%–50%replacement of cement.The optimal ratio was 30%replacement of cement,and the mass ratio of calcined gangue to limestone powder was 2:1.The 3 days compressive strength of this ratio was 28.8 MPa,which was only slightly lower than that of cement.However,the 28 days compressive strength of samples reached 67.5 MPa,which was much higher than that of the reference cement.In the hydration of this cementitious material,not only does the activated coal gangue react with the Ca(OH)_(2)formed by hydration to form C–S–H gel,but CaCO3 also participates in the reaction to form a new phase of carbon aluminate,and the two effects together promote the development of the later strength of the samples.This paper can provide a reference for carbon reduction in the cement production process and comprehensive utilization of coal gangue.
基金Project (2007K06-13) supported by the Science and Technique Research and Development Program of Shaanxi Province, China
文摘Zirconia/stainless steel (ZrO2/SUS316L) functionally graded materials (FGMs) were fabricated by tape casting and laminating. Microstructures of FGMs were observed by optical microscope. Fracture behavior of FGMs in different loading modes and influences of different gradient changes on flexural strength were investigated. The results show that ZrO2/ SUS316L FGMs with graded components at interlayers are obtained after they are sintered in vacuum and pressureless condition at 1 350 ℃. TheⅠ?Ⅱ mixed mode crack creates in composite layer and grows to both sides zigzag while loading on ZrO2 layer. Flexural strengths are 496.4,421.7 and 387.5 MPa when gradient changes are 10%,15% and 20%,but flexural strengths of the corresponding fracture layers are 387.1,334.6 and 282.3 MPa since cracks of FGMs are affected by three-dimensional stress,respectively. The cracks are generated in ZrO2 layer and extend to SUS316L layer while loading is added on SUS316L layer,flexural strength does not change with the graded components and keeps consistent basically.
基金Funded by Social Development Plan of Jiangsu Department of the Science and Technology,Jiangsu,China(No.BS2007038)
文摘Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide（CTAB）as template.The effect of several factors on surface area of products also had been discussed.The products were characterized by FT- IR,HRTEM and N 2 adsorption and desorption isotherm plot methods.There was typical structure as Si-O,Si- OH and Si-O-Si of mesoporous materials in the framework of synthesized materials;the pore size distributions of the products showed a sharp peak at 3.82 nm.The effect of hydrothermal treatment time and the amount of template on the specific surface area of mesoporous materials was important,when the Surf/Si=0.135,and hydrothermal time=12 h,and the surface area of the product reached up to 1 070 m2/g,which was higher than other products.
基金financially supported by the Program of National Natural Science Foundation of China (No. 50971020)
文摘In this paper, the two-flume method was used to study the change laws of the thermal conductivity and thermal expansion coefficient of diamond/Cu composite materials with 100, 300, and 500 cycle numbers, under the action of thermal shock load between-196 and 85 °C; the X-ray diffraction method（XRD） was used to study the change of the residual stress in the thermal shock process of the diamond/Cu composite materials; and the evolution of the fracture microstructure with different thermal shock cycle numbers was observed through scanning electron microscopy（SEM）. The results of the study show that the increase of the binder residue at the interface reduces the thermal shock stability of the diamond/Cu composite materials. In addition, under the thermal shock load between-196 and 85 °C, the residual stress of the diamond/Cu composite materials increases continuously with the increase of the cycle numbers, the increase of residual stress leads to a small amount of interface debonding, an increase of the interfacial thermal resistances, and a decrease of the constraints of low-expansion component on material deformation, thus the thermal conductivity decreases slightly and the thermal expansion coefficient increases slightly.
基金Funded by the Jiangsu Province Industry-University-Research Cooperation Project (No.BY2018314)the Scientific Research Foundation of Jiangsu University of Technology (No.KYY18030)Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents。
文摘3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.
基金supported by the National Natural Science Foundation of China(Nos.12175231 and 11805131),Anhui Natural Science Foundation of China(No.2108085J05)Projects of International Cooperation and Exchanges NSFC(No.51111140389)the Collaborative Innovation Program of the Hefei Science Center,CAS(Nos.2021HSC-CIP020 and 2022HSCCIP009).
文摘Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel P92.The TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 steel.The prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were investigated.Compared to the AR specimen,the PAG size did not change significantly.The fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction ratio.The PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR specimen.Moreover,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.
基金Supported by the National Natural Science Fundation of China(51873146)。
文摘In this paper,the main research work and related reports of materials science research in China’s space technology field during 2020-2022 are summarized.This paper covers Materials Sciences in Space Environment,Materials Sciences for Space Environment,Materials Behavior in Space Environment and Space experimental hardware for material investigation.With the rapid development of China’s space industry,more scientists will be involved in materials science,space technology and earth science researches.In the future,a series of disciplines such as space science,machinery,artificial intelligence,digital twin and big data will be further integrated with materials science,and space materials will also usher in new development opportunities.
基金the financial support of the Key Technologies Research and Development Program(Grant No.2022YFC3003302)the National Natural Science Foundation of China(Grant Nos.51934007 and 52104230).
文摘Deep coal-energy mining frequently results in microseismic(MS)events,which may be a precursor to the risk of rockbursts and pose risks to human safety and infrastructure.Therefore,quantitatively predicting the time,energy,and location(TEL)of future MS events is crucial for understanding and preventing potential catastrophic events.In this study,we introduced the application of spatiotemporal graph convolutional networks(STGCN)to predict the TEL of MS events induced by deep coal-energy mining.Notably,this was the first application of graph convolution networks(GCNs)in the spatiotemporal prediction of MS events.The adjacency matrices of the sensor networks were determined based on the distance between MS sensors,the sensor network graphs we constructed,and GCN was employed to extract the spatiotemporal details of the graphs.The model is simple and versatile.By testing the model with on-site MS monitoring data,our results demonstrated promising efficacy in predicting the TEL of MS events,with the cosine similarity(C)above 0.90 and the mean relative error(MRE)below 0.08.This is critical to improving the safety and operational efficiency of deep coal-energy mining.
文摘Two new Mn(Ⅱ)coordination polymers,namely{[Mn_(2)(HL)(phen)_(3)(H_(2)O)_(2)]·7.5H_(2)O}_n(1)and[Mn_(4)(HL)_(2)(1,4-bib)_(3)(H_(2)O)_(2)]_n(2),were synthesized under hydrothermal conditions by using Mn(Ⅱ)ions and 6-(3',4'-dicarboxylphenoxy)-1,2,4-benzenetricarboxylic acid(H_(5)L)in the presence of N-auxiliary ligands 1,10-phenanthroline(phen)and1,4-bis(1H-imidazol-1-yl)benzene(1,4-bib).The structures of coordination polymers 1 and 2 were characterized by infrared spectroscopy,single-crystal X-ray diffraction,thermogravimetric analysis,and powder X-ray diffraction.Single-crystal X-ray diffraction reveals that 1 has a 1D chain structure based on binuclear Mn(Ⅱ)units,while 2 features a(3,8)-connected 3D network structure based on tetranuclear Mn(Ⅱ)units.Magnetic studies show that 1 and 2exhibit antiferromagnetic interactions between manganese ions.2 shows stronger antiferromagnetic interactions due to the shorter Mn…Mn distances within the tetranuclear manganese units.CCDC:2357601,1;2357602,2.
基金National Natural Science Foundation of China(51572224)Guangdong Young Creative Talents(2023KQNCX039)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515110551)Innovative Team in Higher Educational Institutions of Guangdong Province(2020KCXTD039)2023 Lingnan Normal College Students Innovation and Entrepreneurship Training Program(1742)。
文摘The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.
基金Funded by the National Natural Science Foundation of China(No.51474170)the Foundation of Shaanxi Educational Committee(No.17JK0395)the Xi'an Science and Technology Committee Program(No.GXYD9.2)。
文摘LiGe_(2_(PO_(4))3:Cr^(3+)near-infrared phosphor samples were prepared using high-temperature solid-state method and the corresponding PC-LED devices were prepared.Detailed research was conducted on the photoluminescence characteristics of the samples and the performance of PC-LEDs.Under the excitation of 442 nm blue light,the phosphor obtained by calcination at 1000℃for 4 h exhibited an emission peak at 778 nm in the broadband near-infrared spectrum.The excitation peak of LiGe_(2_(PO_(4))3:Cr^(3+)underwent the energy level transitions,^(4)A_(2)(4F)→^(4)T_(1)(4P)and^(4)A_(2)(4F)→^(4)T_(1)(4F),while the emission peak underwent the energy level transition,^(4)T_(2)(4F)→^(4)A_(2)(4F).By coating the phosphor on the surface of the InGaN blue-light chip,The near-infrared PC-LED was prepared,and a near-infrared LED light source with broadband emission was obtained.At a driving current of 60 mA,the near-infrared light radiation power was 7 mW.The experimental results indicate that LiGe_(2_(PO_(4))3:Cr^(3+)near-infrared phosphor can be used to prepare broadband near-infrared LED light sources based on blue-light chips,which has intriguing applications in near-infrared spectroscopy.
基金Project(BK20241969)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(51971249)supported by the National Natural Science Foundation of China。
文摘As cathode materials for alkali-ion batteries,sodium manganese oxides have been receiving considerable and continuous attention in recent decades.In this work,the structure and environment-dependent stability of NaMn_(2)O_(4) surface were studied based on the first principles calculations.The surface stability diagram of NaMn_(2)O_(4) involving various different terminations of(100),(110)and(111)surfaces was constructed,and the stability of these different terminations could be compared as a function of chemical environment.It is found that the(100)-MnO and(111)-ONa terminations are two more stable terminations under the investigated chemical conditions.And the surface energies of(110)surfaces are negative under the investigated chemical potential,hence,(110)surfaces are unstable.The surface energy of NaMn_(2)O_(4) as a function of O chemical potential is also investigated under constant Na chemical potential.The structure relaxation indicates that the surface rumpling and surface reconstruction can affect the electronic structure of the surface,thereby reducing surface energy and stabilizing the surface.Furthermore,the Wulff shape of NaMn_(2)O_(4) was also constructed based on Gibbs-Wulff theorem.
基金supported by the National Natural Science Foundation of China(No.52301260)the National Science Foundation of Jiangsu Province(No.BK20230712)China Postdoctoral Science Foundation(No.2022M711686).
文摘The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercalation process,thereby affecting the cycling stability and lifespan of sodium-ion batteries(SIBs).In this work,a novel approach involving anionic doping and structural design has been proposed,wherein a two-step in-situ selenization and surface thermal annealing doping process is applied to fabricate a novel configuration material of fluorine-doped MoSe_(2)@nitrogen-doped carbon nanosheets(F-MoSe_(2)@FNC).The obtained F-MoSe_(2)@FNC,benefiting from the dual advantages of structure and F-doping,synergistically promotes and accelerates the stable(de)intercalation of Na^(+).Henceforth,F-MoSe_(2)@FNC demonstrates notable characteristics in terms of reversible specific capacity,boasting a high initial coulombic efficiency of 76.97%,alongside remarkable rate capabilities and cyclic stability.The constructed F-MoSe_(2)@FNC anode-based half cell manifests exceptional longevity,enduring up to 2550 cycles at 10 A·g^(-1)with a specific capacity of 322.04 mAh·g^(-1).Its electrochemical performance surpasses that of MoSe_(2)@NC and Pure MoSe_(2),underscoring the significance of the proposed synergistic modulation.Through comprehensive kinetic analyses,encompassing in-situ electrochemical impedance spectroscopy(EIS),it is elucidated that the F-MoSe_(2)@FNC electrode showcases elevated pseudo-capacitance and rapid diffusion attributes during charge and discharge processes.Furthermore,the assembled full-cell(F-MoSe_(2)@FNC//Na_(3)V_(2)(PO_(4))_(3))attains a notable energy density of 166.94 Wh·kg^(-1).This design provides insights for the optimization of MoSe_(2)electrodes and their applications in SIBs.
基金supported by the National Natural Science Foundation of China(No.52002305)Natural Science Basic Research Program in Shanxi Province of China(Nos.202403021221184,202403021222281)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2025JC-YBMS-478,23JK0424)College Students’Innovation Program of Taiyuan Normal University(No.CXCY2443)。
文摘Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by inherent structural instability and ambiguous structure-kinetics correlation.In this study,Fe NCN crystallites with selectively exposed(002)and{010}facets were precisely engineered and synthesized.Notably,the sodium storage kinetics and electrochemical performance of Fe NCN exhibit facet-dependent variations.Polyhedral-Fe NCN(P-Fe NCN)dominated by{010}facets exhibited a pseudocapacitance-driven storage mechanism and delivered exceptional rate capability(372 m Ah/g at5 A/g)and long cyclability(95.8%capacity retention after 300 cycles at 0.5 A/g).In contrast,sheet-like Fe NCN(S-Fe NCN)with predominant(002)facet exposure displayed diffusion-limited kinetics due to sluggish ion diffusion rate.Crucially,time-resolved operando XRD analysis and DFT simulation bridge this performance gap to mechanistic origins:Fe NCN as an intercalation-conversion type anode,the solid-state diffusion is the rate-determining step during charge/discharge process.Active{010}facets possess numerous broad hexagonal tunnels,coupled with a low diffusion barrier of 0.168 e V along{010}directions.This unique architectural configuration enables rapid sodium-ion transport,thereby shifting the diffusioncontrolled kinetics to intercalation-pseudocapacitive behavior.This discovery establishes active facet exposure as a storage kinetic switch,offering a generalized paradigm for optimizing the rate performance and stability of sodium-ion batteries.
文摘Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.
