The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical r...The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical reaction at low temperatures(573,583,and 593 K),but the limiting step is controlled by boundary layer diffusion at high temperatures(603 and 613 K).The Se-and Te-atom diffusion in the product layer becomes unbalanced as the product layer thickens,with Kirkendall voids generating in the product layer accelerating PbTe particle erosion.After the PbTe impurities in the selenium melt evolve into PbSe and Te,Te is evenly distributed in the selenium melt owing to the solubility of Se and Te.This study serves to clarify the evolution behavior of PbTe impurities in the selenium melt and the reason that Te often occurs in Se.展开更多
Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been d...Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.展开更多
Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated c...Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short.Herein,we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix.The generated Co and LiF both enable fast Li-ion diffusion kinetics,meanwhile,the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites,thereby contributing to uniform Li nucleation and non-dendritic growth.As a result,a dendrite-free Li deposition with a low overpotential(16.1 mV)is achieved,which enables an extended lifespan over 750 h under strict conditions.The full cells with high-mass-loading LiFePO_(4)(11.5 mg/cm^(2))as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4%after undergoing 180 cycles.展开更多
Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during hom...Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during homogenization and the hot deformation behavior of the homogenized ingot were investigated in this study.The results indicate that:(1)the solidified ingot exhibits a typical dendritic microstructure,and significant element segregation occurs,leading to the presence of Ti,Nb,and Mo-rich precipitates in the interdendritic region;(2)Following homogenization,the degree of element segregation in the ingot is significantly reduced.The diffusion coefficients(D)of Ti,Nb,and Mo under various homogenization conditions were calculated.Subsequently,the diffusion constants(D_(0))and activation energies(Q)of Ti,Nb,and Mo were obtained to be 0.01432,0.00397 and 0.00195 cm^(2)/s and 244.851,230.312,and 222.125 kJ/mol,respectively.Finally,the diffusion kinetics formulas for Ti,Nb,and Mo in Alloy 625 Plus were established.After homogenization at 1220℃for 8 h,the alloy exhibits low deformation resistance,a high degree of recrystallization,and optimal deformation coordination ability.Therefore,this represents a rational single-stage homogenization process.展开更多
For the first time, we apply different geospeedometric models to garnet zoning patterns that were obtained in this study from detailed EMP analyses for garnets from eclogites and granulite in the Dabie-Sulu orogen. Va...For the first time, we apply different geospeedometric models to garnet zoning patterns that were obtained in this study from detailed EMP analyses for garnets from eclogites and granulite in the Dabie-Sulu orogen. Various zonings of cation diffusion were preserved in the garnets, enabling the acquirement of average cooling rates for the high-to ultrahigh-pressure rocks without using geochronological approaches. The coesite-bearing hot eclogites yield fast cooling rates of about 20 to 30℃/Ma subsequent to peak metamorphic temperatures, whereas the cold eclogite gives a relatively slow cooling rate of 8℃/Ma at its initial exhumation. A very slow cooling rate of <0.3℃/Ma is obtained for the granulite at Huangtuling, suggesting that the granulite may not be involved in the continental deep subduction.展开更多
Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu...Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu-Co_(1-x)Te@NC HNBs)have been fabricated by chemical etching of Cu Co-ZIF nanoboxes,followed by a successive high-temperature tellurization process.The as-synthesized Cu-Co_(1-x)Te@NC HNBs composite demonstrated faster ionic and electronic diffusion kinetics than the pristine Co Te@NC HNBs electrode.The existence of Co-vacancy promotes the reduction of Gibbs free energy change(ΔG_(H^(*)))and effectively improves the Li~+diffusion coefficient.XPS and theoretical calculations show that performance improvement is ascribed to the electronic interactions between Cu-Co_(1-x)Te and nitrogen-doped carbon(NC)that trigger the shift of the p-band towards facilitation of interfacial charge transfer,which in turn helps boost up the lithium storage property.Besides,the proposed Cu-doping-induced Co-vacancy strategy can also be extended to other conversion-type cobalt-based material(CoSe_(2))in addition to asobtained Cu-Co_(1-x)Se_(2)@NC HNBs anodes for long-life and high-capacity LIBs.More importantly,the fabricated LiCoO_(2)//Cu-Co_(1-x)Te@NC HNBs full cell exhibits a high energy density of 403 Wh kg^(-1)and a power density of 6000 W kg^(-1).We show that the energy/power density reported herein is higher than that of previously studied cobalt-based anodes,indicating the potential application of Cu-Co_(1-x)Te@NC HNBs as a superior electrode material for LIBs.展开更多
The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into wast...The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into waste rubber is of vital importance to improve the performance of rubber modified asphalt,while the related researches are scarce. Diffusion of components of asphalt into waste rubber at different temperatures has been investigated in this work. Rectangle rubber was immersed in asphalt at certain temperature for a period of time. And the mass increment of rubber was measured to determine the diffusion rate of components of asphalt into rubber. The experimental results indicated that the diffusion rate of components of asphalt into waste rubber increases along the temperature,but the diffusion rate of components of fractions oil which is distillated from catalytic cracking slurry is much higher than that of components of asphalt. Compared with asphalt,fractions oil enjoys lower viscosity and better permeability with higher content of saturates and aromatics. All the characteristics are contributed to the efficient diffusion of components of fractions into waste rubber.展开更多
Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performanc...Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.展开更多
In this study,six kinetics models of indomethacin hydrophilic gel patch transdermal in vitro release was established,including zero-level,first-order,Higuchi-level,Ritger-Peppas,Weibull and Hixcon-Crowell dynamic equa...In this study,six kinetics models of indomethacin hydrophilic gel patch transdermal in vitro release was established,including zero-level,first-order,Higuchi-level,Ritger-Peppas,Weibull and Hixcon-Crowell dynamic equations.The chemical permeation enhancers,including 3%and 5%Azone,and iontophoresis were used as the control.Transdermal diffusion tests were performed in vitro and indomethacin was quantified by high performance liquid chromatography system.The transdermal parameter of the Higuchi and Weibull dynamic equations,indicated that Fu’s cupping therapy(FCT)could significantly improve Higuchi and Weibull kinetic parameters in vitro transdermal,increased transdermal rate and permeability coefficient,reduced lagging time.Additionally,statistical analysis speculated the skin barrier function could be restored after 46 h treatment.Hence,as a new physical transdermal drug delivery technology,transdermal permeation effects produced by FCT are obvious,which has the characteristics of traditional Chinese medicine and has important clinical application value.展开更多
Single crystallization has proven to be effective in enhancing the capacity and stability of Ni-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(SNCM)cathode materials,particularly at high cut-off voltages.Nevertheless,the synthesi...Single crystallization has proven to be effective in enhancing the capacity and stability of Ni-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(SNCM)cathode materials,particularly at high cut-off voltages.Nevertheless,the synthesis of high-quality single-crystal particles remains challenging because of severe particle agglomeration and irregular morphologies.Moreover,the limited kinetics of solid-phase Li^(+)diffusion pose a significant concern because of the extended diffusion path in large single-crystal particles.To address these challenges,we developed a Tb-doped single-crystal LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)(SNCM-Tb)cathode material using a straightforward mixed molten salt sintering process.The Tb-doped Ni-rich single crystals presented a quasi-spherical morphology,which is markedly different from those reported in previous studies.Tb^(4+)oping significantly enhanced the dynamic transport of Li^(+)ions in the layered oxide phase by reducing the Ni valence state and creating Li vacancies.A SNCM-Tb material with 1 at%Tb doping shows a Li^(+)diffusion coefficient up to more than 9 times higher than pristine SNCM in the non-diluted state.In situ X-ray diffraction analysis demonstrated a significantly facilitated H1-H2-H3 phase transition in the SNCM-Tb materials,thereby enhancing their rate capacity and structural stability.SNCM-Tb exhibited a reversible capacity of 186.9 mA h g^(-1)at 5 C,retaining 94.6%capacity after 100 cycles at 0.5 C under a 4,5 V cut-off.Our study elucidates the Tb^(4+)doping mechanisms and proposes a scalable method for enhancing the performance of single-crystal Ni-rich NCM materials.展开更多
Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,th...Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.展开更多
Na_(2)FePO_(4)F is a promising sodium ion cathode due to its low cost,non-toxicity,and high stability.However,the sluggish Na^(+)diffusion kinetics and limited intrinsic electronic conductivity critically restrict its...Na_(2)FePO_(4)F is a promising sodium ion cathode due to its low cost,non-toxicity,and high stability.However,the sluggish Na^(+)diffusion kinetics and limited intrinsic electronic conductivity critically restrict its worldwide application.Herein,an anion-substitution strategy is proposed with SiO_(4)^(4-)as the dopant.SiO_(4)^(4-)substitution for PO_(4)^(3-)can apparently alter the localized electronic density and structural configuration in the lattice of Na_(2)FePO_(4)F,effectively elevating the charge transfer efficiency.As a result,the electrochemical reaction kinetics of Na_(2)FePO_(4)F is significantly enhanced,which is well demonstrated by a series of electrochemical characterizations.As-obtained Na_(2.2)Fe(PO_(4))_(0.8)(SiO_(4))_(0.2)F renders a specific capacity of 84.9 m A h g^(-1)within the region of 2.5-4.0 V at 60 mA g^(-1)(0.5 C),good rate capability,and a capacity retention of 70.0% after 1000 cycles at 1.24 A g^(-1)(10 C).Furthermore,the stabilities of the cathode-electrolyte interface and structure are strengthened,which are verified by in situ EIS and ex situ XRD analysis.These findings highlight silicate anion substitution as a promising and cost-effective strategy for overcoming the limitations of Na_(2)FePO_(4)F,contributing to the development of sustainable energy storage solutions.展开更多
Although showing huge potential in prospering the marketplace of all-solid-state lithium metal batteries(ASSLMBs),garnet-type solid electrolytes(Li6.5La3Zr1.5Ta0.6O12,LLZTO)are critically plagued by interface instabil...Although showing huge potential in prospering the marketplace of all-solid-state lithium metal batteries(ASSLMBs),garnet-type solid electrolytes(Li6.5La3Zr1.5Ta0.6O12,LLZTO)are critically plagued by interface instability with Li anode and the vulnerability to Li dendrite,which are attributed to poor Li diffusion kinetic in bulk Li metal.Herein,a LixAg solid solution alloy with high Li diffusion kinetic is reported as a mixed ionelectron conductor(MIEC)alloy anode.The high Li diffusion kinetic stemming from a low eutectic point and a high mutual solubility of LixAg could reduce the Li concentration gradient in the anode,regulate Li electrochemical potential,and change the relative local overpotential for Li stripping/plating in the anode.Notably,Li stripping/plating prefers energetically at the LixAg/current collector interface rather than the LLZTO/LixAg interface.Therefore,the contact loss is avoided at the LLZTO/LixAg interface.As a result,excellent cycling stability(~1,200 h at 0.2 mA/cm2),and dendrites tolerance(critical current density of 1.2 mA/cm2)are demonstrated by using LixAg as anode.Further research has elucidated that those alloys with low eutectic temperature and high mutual solubility with lithium should be focused on,as they would provide and maintain a soft lattice and a high lithium diffusion rate during composition change.This provides a basis for the selection of alloy phases in negative electrode materials,as well as their application in garnet-based ASSLMBs.展开更多
The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0...The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0.75)O_(2)(NNWMO),has been developed to address the limitations of traditional cathode materials.Compared to the pristine Na_(0.67)Ni_(0.25)Mn_(0.75)O_(2)(NNMO),NNWMO exhibits improved reversible capacity,excellent cycle performance,and remarkable rate performance.It can deliver an increased discharge capacity of 142.20 mAh/g at 0.1 C,with an admirable capacity retention of 80.5% after 100 cycles at high voltage.In situ XRD results demonstrate that the rivet effect related to the strong W—O bonds inhibits irreversible phase transition and enhances structural reversibility during charge/discharge processes.High-resolution scanning transmission electron microscopy and X-ray diffraction results confirm successful lattice doping of W^(6+)and increased layer spacing,contributing to favorable sodium ion diffusion kinetics.Density-functional theory(DFT)calculation results further reveal that the smoother Na+ion diffusion dynamics is attributed to the reduced migration energy barrier of Na^(+)with the insertion of W^(6+).This study provides valuable insights into the design of high-performance cathode materials for next-generation SIBs,showcasing the potential for more efficient,stable,and enduring energy storage solutions.展开更多
The microstructure evolution and mechanical properties of Mg-6 Zn-2 Gd-0.5 Zr alloy during homogenization treatment were investigated. The as-cast alloy was found to be composed of dendritic primaryα-Mg matrix, α-Mg...The microstructure evolution and mechanical properties of Mg-6 Zn-2 Gd-0.5 Zr alloy during homogenization treatment were investigated. The as-cast alloy was found to be composed of dendritic primaryα-Mg matrix, α-Mg +W（Mg;Zn;Gd;） eutectic along grain boundaries, and icosahedral quasicrystalline I（Mg;Zn;Gd） phase within α-Mg matrix. During homogenization process, α-Mg +W（Mg;Zn;Gd;） eutectic and I phase gradually dissolved into a-Mg matrix, while some rod-like rare earth hydrides（GdH2）formed within α-Mg matrix. Both the tensile yield strength and the elongation showed a similar tendency as a function of homogenization temperature and holding time. The optimized homogenization parameter was determined to be 505℃ for 16 h according to the microstructure evolution. Furthermore,the diffusion kinetics equation of the solute elements derived from the Gauss model was established to predict the segregation ratio of Gd element as a function of holding time, which was proved to be effective to evaluate the homogenization effect of the experimental alloy.展开更多
Na-ion diffusion kinetics is a key factor that decided the charge/discharge rate of the electrode materials in Na-ion batteries.In this work,two extreme concentrations of NaMnO_(2) and Na_(2/3)Li_(1/6)Mn_(5/6)O_(2) ar...Na-ion diffusion kinetics is a key factor that decided the charge/discharge rate of the electrode materials in Na-ion batteries.In this work,two extreme concentrations of NaMnO_(2) and Na_(2/3)Li_(1/6)Mn_(5/6)O_(2) are considered,namely,the vacancy migration of Na ions in the fully intercalated and the migration of Na ions in the fully de-intercalated.The Na-vacancy and Na^(+)distribution in NaMnO_(2) migrated along oxygen dumbbell hop(ODH)and tetrahedral site hop(TSH),and the migration energy barriers were 0.374 and 0.296 eV,respectively.In NaLi_(1/6)Mn_(5/6)O_(2),the inhomogeneity of Li doping leads to the narrowing of the interlayer spacing by 0.9%and the increase of the energy barrier by 53.8%.On the other hand,due to the alleviation of Jahn-Teller effect of neighboring Mn,the bonding strength of Mn-O was enhanced,so that the energy barrier of path 2-3 in Mn-L1 and Mn-L2 was the lowest,which was 0.234 and 0.424 eV,respectively.In Na_(1/6)Li_(1/6)Mn_(5/6)O_(2),the migration energy barriers of Na-L2 and Na-L3 are 1.233 and 0.779 eV,respectively,because Li+migrates from the transition(TM)layer to the alkali metal(AM)layer with Na^(+)migration,which requires additional energy.展开更多
DifFusion couples, Fe-6.8 wt% Al-1.0 wt% Si/Fe and Fe-6.3 wt% Al-0.9 wt% Si/Fe were constructed and separately annealed at 1050℃ for 3 h and at 1000℃ for 64 h. The concentration profiles of Fe, Al and Si atoms in th...DifFusion couples, Fe-6.8 wt% Al-1.0 wt% Si/Fe and Fe-6.3 wt% Al-0.9 wt% Si/Fe were constructed and separately annealed at 1050℃ for 3 h and at 1000℃ for 64 h. The concentration profiles of Fe, Al and Si atoms in these couples were measured by electron probe micro-analysis （EPMA）, while the diffusion behavior was also simulated by coupling thermodynamic and kinetic properties of Fe-Al-Si system. The simulation results were in good agreement with the measured concentration profiles showing the validity of dynamic parameters of Fe-Al-Si system, Calculation was made for Fe-7 wt% Al-1 wt% Si/Fe diffusion couples at 1000℃ with different diffusion time. Silicon uphill was found under the influence of aluminum.展开更多
Aqueous zinc ion battery(ZIB)with many virtues such as high safety,cost-effective,and good environmental compatibility is a large-scale energy storage technology with great application potential.Nevertheless,its appli...Aqueous zinc ion battery(ZIB)with many virtues such as high safety,cost-effective,and good environmental compatibility is a large-scale energy storage technology with great application potential.Nevertheless,its application is severely hindered by the slow diffusion of zinc ions in desirable cathode materials.Herein,a technique of water-incorporation coupled with oxygen-vacancy modulation is exploited to improve the zinc ions diffusion kinetics in vanadium pentoxide(V_(2)O_5)cathode for ZIB.The incorporated water molecules replace lattice oxygen in V_(2)O_5,and function as pillars to expand interlayer distance.So the structural stability can be enhanced,and the zinc ions diffusion kinetics might also be promoted during the repeated intercalation/deintercalation.Meanwhile,the lattice water molecules can effectively enhance conductivity due to the electronic density modulation effect.Consequently,the modulated V_(2)O_5(H-V_(2)O_5)cathode behaves with superior rate capacity and stable durability,achieving 234 mA h g^(-1)over 9000 cycles even at 20 A g^(-1).Furthermore,a flexible all-solid-state(ASS)ZIB has been constructed,exhibiting an admirable energy density of 196.6 Wh kg^(-1)and impressive power density of 20.4 kW kg^(-1)as well as excellent long-term lifespan.Importantly,the assembled flexible ASS ZIB would be able to work in a large temperature span(from-20 to 70℃).Additionally,we also uncover the energy storage mechanism of the H-V_(2)O_5 electrode,offering a novel approach for creating high-kinetics cathodes for multivalent ion storage.展开更多
Mixed metal sulfides have been widely used as anode material of sodium-ion batteries(SIBs)because of their excellent conductivity and sodium ion storage performance.Herein,ReS_(2)@NiS_(2)heterostructures have been tri...Mixed metal sulfides have been widely used as anode material of sodium-ion batteries(SIBs)because of their excellent conductivity and sodium ion storage performance.Herein,ReS_(2)@NiS_(2)heterostructures have been triumphantly designed and prepared through anchoring ReS_(2)nanosheet arrays on the surface of NiS_(2)hollow nanosphere.Specifically,the carbon nanospheres was used as hard template to synthesize NiS_(2)hollow spheres as the substrate and then the ultrathin two-dimensional ReS_(2)nanosheet arrays were uniformly grown on the surface of NiS_(2).The internal hollow property provides sufficient space to relieve the volume expansion,and the outer two-dimensional nanosheet realizes the rapid electron transport and insertion/extraction of Na^(+).Owing to the great improvement of the transport kinetics of Na^(+),NiS_(2)@ReS_(2)heterostructure electrode can achieve a high specific capacity of 400 mAh/g at the high current density of 1 A/g and still maintain a stable cycle stability even after 220 cycles.This hard template method not only paves a new way for the design and construct binary metal sulfide heterostructure electrode materials with outstanding electrochemical performance for Na^(+)batteries but also open up the potential applications of anode materials of SIBs.展开更多
This paper investigates the monomer kinetics of polymer dispersed liquid crystal （PDLC） grating. Fourier transform infrared （FTIR） spectra are used in the studies of photoreaction kinetics. The results indicate th...This paper investigates the monomer kinetics of polymer dispersed liquid crystal （PDLC） grating. Fourier transform infrared （FTIR） spectra are used in the studies of photoreaction kinetics. The results indicate that there is a relative stable stage arises after a very short initial stage. Based on FTIR studies, the monomer diffusion equation is deduced and necessary numerical simulations are carried out to analyse the monomer conversion which is an important point to improve phase separation structure of PDLC grating. Some simulation results have a good agreement with experimental data. In addition, the effects induced by monomer diffusion constant D and diffusion-polymerization-ratio rate R are discussed. Results show that monomer conversion can be improved by increasing value of D. Besides, a good equilibrium state （R = 1） is more beneficial to the diffusion of monomer which is important in the process of phase separation.展开更多
基金National Key Research and Development Program of China(No.2022YFC2904900)the National Natural Science Foundation of China(No.U1902221).
文摘The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical reaction at low temperatures(573,583,and 593 K),but the limiting step is controlled by boundary layer diffusion at high temperatures(603 and 613 K).The Se-and Te-atom diffusion in the product layer becomes unbalanced as the product layer thickens,with Kirkendall voids generating in the product layer accelerating PbTe particle erosion.After the PbTe impurities in the selenium melt evolve into PbSe and Te,Te is evenly distributed in the selenium melt owing to the solubility of Se and Te.This study serves to clarify the evolution behavior of PbTe impurities in the selenium melt and the reason that Te often occurs in Se.
基金National Natural Science Foundation of China (61761047 and 41876055)Program for Innovative Research Team (in Science and Technology) in University of Yunnan Province。
文摘Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.
基金financially supported by the National Natural Science Foundation of China(Nos.22279097,52172217)Natural Science Foundation of Guangdong Province(No.2021A1515010144)Shenzhen Science and Technology Program(No.JCYJ20210324120400002).
文摘Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short.Herein,we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix.The generated Co and LiF both enable fast Li-ion diffusion kinetics,meanwhile,the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites,thereby contributing to uniform Li nucleation and non-dendritic growth.As a result,a dendrite-free Li deposition with a low overpotential(16.1 mV)is achieved,which enables an extended lifespan over 750 h under strict conditions.The full cells with high-mass-loading LiFePO_(4)(11.5 mg/cm^(2))as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4%after undergoing 180 cycles.
基金Project(52174303)supported by the National Natural Science Foundation of ChinaProject(2023JH2/101700302)supported by the Joint Program of Science and Technology Plans in Liaoning Province,China。
文摘Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during homogenization and the hot deformation behavior of the homogenized ingot were investigated in this study.The results indicate that:(1)the solidified ingot exhibits a typical dendritic microstructure,and significant element segregation occurs,leading to the presence of Ti,Nb,and Mo-rich precipitates in the interdendritic region;(2)Following homogenization,the degree of element segregation in the ingot is significantly reduced.The diffusion coefficients(D)of Ti,Nb,and Mo under various homogenization conditions were calculated.Subsequently,the diffusion constants(D_(0))and activation energies(Q)of Ti,Nb,and Mo were obtained to be 0.01432,0.00397 and 0.00195 cm^(2)/s and 244.851,230.312,and 222.125 kJ/mol,respectively.Finally,the diffusion kinetics formulas for Ti,Nb,and Mo in Alloy 625 Plus were established.After homogenization at 1220℃for 8 h,the alloy exhibits low deformation resistance,a high degree of recrystallization,and optimal deformation coordination ability.Therefore,this represents a rational single-stage homogenization process.
文摘For the first time, we apply different geospeedometric models to garnet zoning patterns that were obtained in this study from detailed EMP analyses for garnets from eclogites and granulite in the Dabie-Sulu orogen. Various zonings of cation diffusion were preserved in the garnets, enabling the acquirement of average cooling rates for the high-to ultrahigh-pressure rocks without using geochronological approaches. The coesite-bearing hot eclogites yield fast cooling rates of about 20 to 30℃/Ma subsequent to peak metamorphic temperatures, whereas the cold eclogite gives a relatively slow cooling rate of 8℃/Ma at its initial exhumation. A very slow cooling rate of <0.3℃/Ma is obtained for the granulite at Huangtuling, suggesting that the granulite may not be involved in the continental deep subduction.
基金the Natural Science Foundation of Anhui Province Higher Education Institutions(No.KJ2021A0501)the Foundation of Scientific Research Project of Anhui Polytechnic University(No.Xjky2020090)+4 种基金the Anhui Laboratory of Functional Coordinated Complexes for Materials Chemistry and Application(Nos.LFCCMCA-01 and LFCCMCA-06)the Scientific Research Launch Project of Anhui Polytechnic University(No.2020YQQ057)the Innovation and Entrepreneurship Training Program for College Students in Anhui Province(No.S202110363265)the National Key Research and Development Program of China(2019YFA0705702)the National Natural Science Foundation of China(21902188)。
文摘Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu-Co_(1-x)Te@NC HNBs)have been fabricated by chemical etching of Cu Co-ZIF nanoboxes,followed by a successive high-temperature tellurization process.The as-synthesized Cu-Co_(1-x)Te@NC HNBs composite demonstrated faster ionic and electronic diffusion kinetics than the pristine Co Te@NC HNBs electrode.The existence of Co-vacancy promotes the reduction of Gibbs free energy change(ΔG_(H^(*)))and effectively improves the Li~+diffusion coefficient.XPS and theoretical calculations show that performance improvement is ascribed to the electronic interactions between Cu-Co_(1-x)Te and nitrogen-doped carbon(NC)that trigger the shift of the p-band towards facilitation of interfacial charge transfer,which in turn helps boost up the lithium storage property.Besides,the proposed Cu-doping-induced Co-vacancy strategy can also be extended to other conversion-type cobalt-based material(CoSe_(2))in addition to asobtained Cu-Co_(1-x)Se_(2)@NC HNBs anodes for long-life and high-capacity LIBs.More importantly,the fabricated LiCoO_(2)//Cu-Co_(1-x)Te@NC HNBs full cell exhibits a high energy density of 403 Wh kg^(-1)and a power density of 6000 W kg^(-1).We show that the energy/power density reported herein is higher than that of previously studied cobalt-based anodes,indicating the potential application of Cu-Co_(1-x)Te@NC HNBs as a superior electrode material for LIBs.
基金supported by State Key Laboratory of Heavy Oil Processing,China University of Petroleum
文摘The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into waste rubber is of vital importance to improve the performance of rubber modified asphalt,while the related researches are scarce. Diffusion of components of asphalt into waste rubber at different temperatures has been investigated in this work. Rectangle rubber was immersed in asphalt at certain temperature for a period of time. And the mass increment of rubber was measured to determine the diffusion rate of components of asphalt into rubber. The experimental results indicated that the diffusion rate of components of asphalt into waste rubber increases along the temperature,but the diffusion rate of components of fractions oil which is distillated from catalytic cracking slurry is much higher than that of components of asphalt. Compared with asphalt,fractions oil enjoys lower viscosity and better permeability with higher content of saturates and aromatics. All the characteristics are contributed to the efficient diffusion of components of fractions into waste rubber.
基金supported by the Key Project of Natural Science Fund of Shandong Province (ZR2011BZ008)the Marine Renewable Energy Special Fund Project from the State Oceanic Administration PRC (GHME2011GD04)+2 种基金the Scientific and Technology Development Plan Project of Shandong Province,China (2008GG10007003)the Key Laboratory of Submarine Geoscience and Exploring Technology of the Ministry of Education,Ocean University of China (Grant No. 2008-01)the Key Laboratory of Marine Environment & Ecology,Ministry of Education (Grant No. 2008010)
文摘Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.
基金This work was supported by the Projects[NO.20154030 and NO.(2017)5655]from the Science and Technology Department of Guizhou Province and the National Natural Science Foundation of China(No.81873020).
文摘In this study,six kinetics models of indomethacin hydrophilic gel patch transdermal in vitro release was established,including zero-level,first-order,Higuchi-level,Ritger-Peppas,Weibull and Hixcon-Crowell dynamic equations.The chemical permeation enhancers,including 3%and 5%Azone,and iontophoresis were used as the control.Transdermal diffusion tests were performed in vitro and indomethacin was quantified by high performance liquid chromatography system.The transdermal parameter of the Higuchi and Weibull dynamic equations,indicated that Fu’s cupping therapy(FCT)could significantly improve Higuchi and Weibull kinetic parameters in vitro transdermal,increased transdermal rate and permeability coefficient,reduced lagging time.Additionally,statistical analysis speculated the skin barrier function could be restored after 46 h treatment.Hence,as a new physical transdermal drug delivery technology,transdermal permeation effects produced by FCT are obvious,which has the characteristics of traditional Chinese medicine and has important clinical application value.
基金financial support from the horizontal project“Research and Application of All-Solid-State Lithium-Ion Battery Technology” (MH20220255)from Zibo Torch Energy Co.,Ltdthe Heilongjiang Touyan Innovation Team Program (HITTY20190033)+1 种基金Zibo Torch Energy Co.,Ltd.China State Shipbuilding Corporation,Limited for their financial support。
文摘Single crystallization has proven to be effective in enhancing the capacity and stability of Ni-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(SNCM)cathode materials,particularly at high cut-off voltages.Nevertheless,the synthesis of high-quality single-crystal particles remains challenging because of severe particle agglomeration and irregular morphologies.Moreover,the limited kinetics of solid-phase Li^(+)diffusion pose a significant concern because of the extended diffusion path in large single-crystal particles.To address these challenges,we developed a Tb-doped single-crystal LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)(SNCM-Tb)cathode material using a straightforward mixed molten salt sintering process.The Tb-doped Ni-rich single crystals presented a quasi-spherical morphology,which is markedly different from those reported in previous studies.Tb^(4+)oping significantly enhanced the dynamic transport of Li^(+)ions in the layered oxide phase by reducing the Ni valence state and creating Li vacancies.A SNCM-Tb material with 1 at%Tb doping shows a Li^(+)diffusion coefficient up to more than 9 times higher than pristine SNCM in the non-diluted state.In situ X-ray diffraction analysis demonstrated a significantly facilitated H1-H2-H3 phase transition in the SNCM-Tb materials,thereby enhancing their rate capacity and structural stability.SNCM-Tb exhibited a reversible capacity of 186.9 mA h g^(-1)at 5 C,retaining 94.6%capacity after 100 cycles at 0.5 C under a 4,5 V cut-off.Our study elucidates the Tb^(4+)doping mechanisms and proposes a scalable method for enhancing the performance of single-crystal Ni-rich NCM materials.
基金support of the National Natural Science Foundation of China(Grant No.22225801,22178217 and 22308216)supported by the Fundamental Research Funds for the Central Universities,conducted at Tongji University.
文摘Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.
基金funding support from the Beijing Natural Science Foundation(2252055)the National Natural Science Foundation of China(52072033 and 52271234)+1 种基金the State Key Laboratory of Clean Energy Utilization(Open Fund Project,ZJUCEU2024010)the BIT Research and Innovation Promoting Project(2024YCXY040,GIIP2023-34)。
文摘Na_(2)FePO_(4)F is a promising sodium ion cathode due to its low cost,non-toxicity,and high stability.However,the sluggish Na^(+)diffusion kinetics and limited intrinsic electronic conductivity critically restrict its worldwide application.Herein,an anion-substitution strategy is proposed with SiO_(4)^(4-)as the dopant.SiO_(4)^(4-)substitution for PO_(4)^(3-)can apparently alter the localized electronic density and structural configuration in the lattice of Na_(2)FePO_(4)F,effectively elevating the charge transfer efficiency.As a result,the electrochemical reaction kinetics of Na_(2)FePO_(4)F is significantly enhanced,which is well demonstrated by a series of electrochemical characterizations.As-obtained Na_(2.2)Fe(PO_(4))_(0.8)(SiO_(4))_(0.2)F renders a specific capacity of 84.9 m A h g^(-1)within the region of 2.5-4.0 V at 60 mA g^(-1)(0.5 C),good rate capability,and a capacity retention of 70.0% after 1000 cycles at 1.24 A g^(-1)(10 C).Furthermore,the stabilities of the cathode-electrolyte interface and structure are strengthened,which are verified by in situ EIS and ex situ XRD analysis.These findings highlight silicate anion substitution as a promising and cost-effective strategy for overcoming the limitations of Na_(2)FePO_(4)F,contributing to the development of sustainable energy storage solutions.
基金supported by the Natural Science Foundation of China(Grant 51977097,52207234)the Science and Technology Project of State Grid Corporation of China(Grant No.5419-202199552A-0-5-ZN).
文摘Although showing huge potential in prospering the marketplace of all-solid-state lithium metal batteries(ASSLMBs),garnet-type solid electrolytes(Li6.5La3Zr1.5Ta0.6O12,LLZTO)are critically plagued by interface instability with Li anode and the vulnerability to Li dendrite,which are attributed to poor Li diffusion kinetic in bulk Li metal.Herein,a LixAg solid solution alloy with high Li diffusion kinetic is reported as a mixed ionelectron conductor(MIEC)alloy anode.The high Li diffusion kinetic stemming from a low eutectic point and a high mutual solubility of LixAg could reduce the Li concentration gradient in the anode,regulate Li electrochemical potential,and change the relative local overpotential for Li stripping/plating in the anode.Notably,Li stripping/plating prefers energetically at the LixAg/current collector interface rather than the LLZTO/LixAg interface.Therefore,the contact loss is avoided at the LLZTO/LixAg interface.As a result,excellent cycling stability(~1,200 h at 0.2 mA/cm2),and dendrites tolerance(critical current density of 1.2 mA/cm2)are demonstrated by using LixAg as anode.Further research has elucidated that those alloys with low eutectic temperature and high mutual solubility with lithium should be focused on,as they would provide and maintain a soft lattice and a high lithium diffusion rate during composition change.This provides a basis for the selection of alloy phases in negative electrode materials,as well as their application in garnet-based ASSLMBs.
基金supported by the Talent Recruitment Program of Sichuan University of Science and Engineering(2023RC06)the Innovation Center for Chenguang High-Performance Fluorine Material(SCFY2207)+3 种基金the Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities(2022JXY04)College Students Innovation and Entrepreneurship Training Program(S20221062208,S202010622054)the Scientific Research and Innovation Team Program of Sichuan University of Science and Engineering(SUSE652B008)the Central Government Guide Local Science and Technology Development Fund(24ZYTXJS0055).
文摘The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0.75)O_(2)(NNWMO),has been developed to address the limitations of traditional cathode materials.Compared to the pristine Na_(0.67)Ni_(0.25)Mn_(0.75)O_(2)(NNMO),NNWMO exhibits improved reversible capacity,excellent cycle performance,and remarkable rate performance.It can deliver an increased discharge capacity of 142.20 mAh/g at 0.1 C,with an admirable capacity retention of 80.5% after 100 cycles at high voltage.In situ XRD results demonstrate that the rivet effect related to the strong W—O bonds inhibits irreversible phase transition and enhances structural reversibility during charge/discharge processes.High-resolution scanning transmission electron microscopy and X-ray diffraction results confirm successful lattice doping of W^(6+)and increased layer spacing,contributing to favorable sodium ion diffusion kinetics.Density-functional theory(DFT)calculation results further reveal that the smoother Na+ion diffusion dynamics is attributed to the reduced migration energy barrier of Na^(+)with the insertion of W^(6+).This study provides valuable insights into the design of high-performance cathode materials for next-generation SIBs,showcasing the potential for more efficient,stable,and enduring energy storage solutions.
基金supported by the National Natural Science Foundation of China(Nos.51771152,51227001 and 51420105005)the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(No.138-QP-2015)
文摘The microstructure evolution and mechanical properties of Mg-6 Zn-2 Gd-0.5 Zr alloy during homogenization treatment were investigated. The as-cast alloy was found to be composed of dendritic primaryα-Mg matrix, α-Mg +W（Mg;Zn;Gd;） eutectic along grain boundaries, and icosahedral quasicrystalline I（Mg;Zn;Gd） phase within α-Mg matrix. During homogenization process, α-Mg +W（Mg;Zn;Gd;） eutectic and I phase gradually dissolved into a-Mg matrix, while some rod-like rare earth hydrides（GdH2）formed within α-Mg matrix. Both the tensile yield strength and the elongation showed a similar tendency as a function of homogenization temperature and holding time. The optimized homogenization parameter was determined to be 505℃ for 16 h according to the microstructure evolution. Furthermore,the diffusion kinetics equation of the solute elements derived from the Gauss model was established to predict the segregation ratio of Gd element as a function of holding time, which was proved to be effective to evaluate the homogenization effect of the experimental alloy.
基金Projects(51602352,51974373,51874358,51772333,61533020) supported by the National Natural Science Foundation of ChinaProject(2019JZZY020123) supported by the Major Scientific and Technological Innovation Projects of Shandong Province,China。
文摘Na-ion diffusion kinetics is a key factor that decided the charge/discharge rate of the electrode materials in Na-ion batteries.In this work,two extreme concentrations of NaMnO_(2) and Na_(2/3)Li_(1/6)Mn_(5/6)O_(2) are considered,namely,the vacancy migration of Na ions in the fully intercalated and the migration of Na ions in the fully de-intercalated.The Na-vacancy and Na^(+)distribution in NaMnO_(2) migrated along oxygen dumbbell hop(ODH)and tetrahedral site hop(TSH),and the migration energy barriers were 0.374 and 0.296 eV,respectively.In NaLi_(1/6)Mn_(5/6)O_(2),the inhomogeneity of Li doping leads to the narrowing of the interlayer spacing by 0.9%and the increase of the energy barrier by 53.8%.On the other hand,due to the alleviation of Jahn-Teller effect of neighboring Mn,the bonding strength of Mn-O was enhanced,so that the energy barrier of path 2-3 in Mn-L1 and Mn-L2 was the lowest,which was 0.234 and 0.424 eV,respectively.In Na_(1/6)Li_(1/6)Mn_(5/6)O_(2),the migration energy barriers of Na-L2 and Na-L3 are 1.233 and 0.779 eV,respectively,because Li+migrates from the transition(TM)layer to the alkali metal(AM)layer with Na^(+)migration,which requires additional energy.
基金supported by the National Natural Science Foundation of China under Grant Nos. 50971137 and 50934011the National Basic Research program of China under GrantNo. 2010CB630802.
文摘DifFusion couples, Fe-6.8 wt% Al-1.0 wt% Si/Fe and Fe-6.3 wt% Al-0.9 wt% Si/Fe were constructed and separately annealed at 1050℃ for 3 h and at 1000℃ for 64 h. The concentration profiles of Fe, Al and Si atoms in these couples were measured by electron probe micro-analysis （EPMA）, while the diffusion behavior was also simulated by coupling thermodynamic and kinetic properties of Fe-Al-Si system. The simulation results were in good agreement with the measured concentration profiles showing the validity of dynamic parameters of Fe-Al-Si system, Calculation was made for Fe-7 wt% Al-1 wt% Si/Fe diffusion couples at 1000℃ with different diffusion time. Silicon uphill was found under the influence of aluminum.
基金the Natural Science Foundation of Guangdong Province of China(2023A1515011672)the Educational Commission of Guangdong Province of China(2022ZDZX3048)+1 种基金the Research projects for college students of Guangdong Industry Polytechnic College(XSKYL202208)the Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province,School of Chemistry and Chemical Engineering,Hainan Normal University,Haikou,South Longkun Rd.571158,P.R.China(KFKT2023003)。
文摘Aqueous zinc ion battery(ZIB)with many virtues such as high safety,cost-effective,and good environmental compatibility is a large-scale energy storage technology with great application potential.Nevertheless,its application is severely hindered by the slow diffusion of zinc ions in desirable cathode materials.Herein,a technique of water-incorporation coupled with oxygen-vacancy modulation is exploited to improve the zinc ions diffusion kinetics in vanadium pentoxide(V_(2)O_5)cathode for ZIB.The incorporated water molecules replace lattice oxygen in V_(2)O_5,and function as pillars to expand interlayer distance.So the structural stability can be enhanced,and the zinc ions diffusion kinetics might also be promoted during the repeated intercalation/deintercalation.Meanwhile,the lattice water molecules can effectively enhance conductivity due to the electronic density modulation effect.Consequently,the modulated V_(2)O_5(H-V_(2)O_5)cathode behaves with superior rate capacity and stable durability,achieving 234 mA h g^(-1)over 9000 cycles even at 20 A g^(-1).Furthermore,a flexible all-solid-state(ASS)ZIB has been constructed,exhibiting an admirable energy density of 196.6 Wh kg^(-1)and impressive power density of 20.4 kW kg^(-1)as well as excellent long-term lifespan.Importantly,the assembled flexible ASS ZIB would be able to work in a large temperature span(from-20 to 70℃).Additionally,we also uncover the energy storage mechanism of the H-V_(2)O_5 electrode,offering a novel approach for creating high-kinetics cathodes for multivalent ion storage.
基金supported by the Natural Science Foundation of Guangdong Province(No.2020A1515010886).
文摘Mixed metal sulfides have been widely used as anode material of sodium-ion batteries(SIBs)because of their excellent conductivity and sodium ion storage performance.Herein,ReS_(2)@NiS_(2)heterostructures have been triumphantly designed and prepared through anchoring ReS_(2)nanosheet arrays on the surface of NiS_(2)hollow nanosphere.Specifically,the carbon nanospheres was used as hard template to synthesize NiS_(2)hollow spheres as the substrate and then the ultrathin two-dimensional ReS_(2)nanosheet arrays were uniformly grown on the surface of NiS_(2).The internal hollow property provides sufficient space to relieve the volume expansion,and the outer two-dimensional nanosheet realizes the rapid electron transport and insertion/extraction of Na^(+).Owing to the great improvement of the transport kinetics of Na^(+),NiS_(2)@ReS_(2)heterostructure electrode can achieve a high specific capacity of 400 mAh/g at the high current density of 1 A/g and still maintain a stable cycle stability even after 220 cycles.This hard template method not only paves a new way for the design and construct binary metal sulfide heterostructure electrode materials with outstanding electrochemical performance for Na^(+)batteries but also open up the potential applications of anode materials of SIBs.
基金supported by Natural Science Foundation of China (Grants Nos 60578035 and 50473040)Science Foundation of Jilin Province,China (Grant Nos 20050520 and 20050321-2)
文摘This paper investigates the monomer kinetics of polymer dispersed liquid crystal （PDLC） grating. Fourier transform infrared （FTIR） spectra are used in the studies of photoreaction kinetics. The results indicate that there is a relative stable stage arises after a very short initial stage. Based on FTIR studies, the monomer diffusion equation is deduced and necessary numerical simulations are carried out to analyse the monomer conversion which is an important point to improve phase separation structure of PDLC grating. Some simulation results have a good agreement with experimental data. In addition, the effects induced by monomer diffusion constant D and diffusion-polymerization-ratio rate R are discussed. Results show that monomer conversion can be improved by increasing value of D. Besides, a good equilibrium state （R = 1） is more beneficial to the diffusion of monomer which is important in the process of phase separation.
