High-entropy oxides(HEOs)have gained great attention as an emerging kind of highperformance anode materials for lithium-ion batteries(LIBs)due to the entropy stabilization and multi-principal synergistic effect.Herein...High-entropy oxides(HEOs)have gained great attention as an emerging kind of highperformance anode materials for lithium-ion batteries(LIBs)due to the entropy stabilization and multi-principal synergistic effect.Herein,the porous perovskite-type RE(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3)(RE(=La,Sm,and Gd)is the abbreviation of rare earth)HEOs were successfully synthesized by a solution combustion synthesis(SCS)method.Owing to the synergistic effect of lattice distortion and oxygen vacancies(Ov),the Gd(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3) electrode exhibits superior high-rate lithium-ion storage performance and excellent cycling stability.A reversible capacity of 403 mAh·g^(-1) at a current rate of 0.2 A·g^(-1) after 500 cycles and a superior high-rate capacity of 394 mAh·g^(-1)even at 1.0 A·g^(-1)after 500 cycles are achieved.Meanwhile,the Gd(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3) electrode also exhibits a pronounced pseudo-capacitive behavior,contributing to an additional capacity.By adjusting and balancing the lattice distortion and oxygen vacancies of the electrode materials,the lithium-ion storage performance can be further regulated.展开更多
Lattice distortion represents the fundamental factor of crystalline materials and contributes significantly to structural-related properties.Herein,we discover an unexpected temperature-induced lattice distortion in C...Lattice distortion represents the fundamental factor of crystalline materials and contributes significantly to structural-related properties.Herein,we discover an unexpected temperature-induced lattice distortion in CuGeO_(3) nanocrystals,resulting in color changes of CuGeO_(3).The structural distortions in CuGeO_(3) nanocrystals are characterized by Rietveld analysis in detail,where its cell parameter b and cell volume reveal first decrease and then increase characteristics and correspond well with the XRD patterns and Raman spectra.Besides,both the experimental characterizations and theoretical calculations confirm that the optical and band structural changes mainly arise from the twisted octahedral field of[CuO_(6)],where the lattice distortions regulate the crystal field splitting energy of[CuO_(6)]and account for its changed d-d transition.Furthermore,tetracycline photodegradation is employed as an example to evaluate the effect of lattice distortion on photocatalytic performance,which also highlights the importance of modulating lattice distortion in photocatalysis.This work provides an approach to simply regulate the lattice distortion for nanorods by manipulating calcination temperatures.展开更多
Out-of-plane weak ferromagnetic(OWFM)spin arrangements with topological properties can realize a series of interesting physical properties.However,this spin structure tends to exist at low temperatures.The OWFM struct...Out-of-plane weak ferromagnetic(OWFM)spin arrangements with topological properties can realize a series of interesting physical properties.However,this spin structure tends to exist at low temperatures.The OWFM structure can also be induced at room temperature by hydrostatic pressure,whereas this isotropic approach tends to form helical AFM structures.We report the OWFM spin arrangement in single crystal Mn_(3)Sn by an anisotropic strategy of high-stressconstrained compression deformation at room temperature.Both experimental and theoretical simulation results show that the alignment of the OWFM spin structure is due to the distortion of the atomic scale caused by the strain energy during deformation.The OWFM spin arrangement can significantly change the magnetic property of Mn_(3)Sn.As a result,the remanent magnetization M_(r)for the deformed sample(0.056μ_(B)/f.u.)is about eleven times that for the pre-deformed sample(0.005μ_(B)/f.u.),and the coercivity(H_(c))increases from 0 k Oe(pre-deformed sample)to 6.02 k Oe(deformed sample).Our findings provide a way to generate the OWFM spin structure at room temperature and may give fresh ideas for creating antiferromagnetic materials with excellent physical properties.展开更多
Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2...Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2)/o-CoSe_(2)as the oxygen electrode of lithium-oxygen batteries(LOBs)to improve its cycle stability.The heterogeneous interface inside c-CoSe_(2)/o-CoSe_(2)leads to an increase in the covalence bonds between Co and Se ions,which greatly enhances the robustness of the crystal lattice,thereby improving the stability of the catalyst.In addition,the strong interaction between the mixed phases is favorable for adjusting the electron density around the active sites and boosting oxygen electrode kinetics.Moreover,the epitaxial growth of o-CoSe_(2)on c-CoSe_(2)will cause abundant heterogeneous interfaces and slight lattice distortion along the interfaces,thereby providing sufficient catalytic reaction sites.The DFT calculation results show that the optimized adsorption of intermediates at the heterogeneous interface plays an important role in boosting oxygen electrode reactions and improving the electrochemical performance of LOBs.The experimental results show that LOBs with the c-CoSe_(2)/o-CoSe_(2)electrodes exhibit outstanding performance,including large specific capacity of about 23,878 m A h g^(-1),high coulombic efficiency of up to 93.66%,and excellent stability of over 176 cycles(1410 h).展开更多
Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ranges.However,lit...Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ranges.However,little attention has been paid to the evolution of lattice distortion with temperature decreasing and its effects on deformation behavior and magnetic state transition.In this work,we carry out in situ synchrotron radiation based X-ray powder diffraction(SR-XRD)experiments from 293 to 123 K aiming for determining lattice distortion evolutions of Cr Co Ni MEA,Cr Fe Co Ni and Cr Mn Fe Co Ni HEAs.Magnetic measurements at corresponding low temperatures and cryogenic ranges are further conducted.The in situ SR-XRD results demonstrate a general reduction of lattice distortion magnitude with temperature decreasing,which shows a similar tendency with that of reported stacking fault energy(SFE)values.It is thus suggested that lattice distortion reduction possibly makes a critical contribution to deformation mechanism transition.The magnetic measurement results show a clear ferromagnetic transition of Cr Fe Co Ni HEA when temperature is below 173 K.While,no obvious magnetic state transition is observed for Cr Co Ni MEA and Cr Mn Fe Co Ni HEA.The present findings on lattice distortion evolutions will pave the way for designing targeted HEAs with particular properties.展开更多
Hydrogen production through hydrogen evolution reaction(HER)offers a promising solution to combat climate change by replacing fossil fuels with clean energy sources.However,the widespread adoption of efficient electro...Hydrogen production through hydrogen evolution reaction(HER)offers a promising solution to combat climate change by replacing fossil fuels with clean energy sources.However,the widespread adoption of efficient electrocatalysts,such as platinum(Pt),has been hindered by their high cost.In this study,we developed an easy-to-implement method to create ultrathin Pt nanomembranes,which catalyze HER at a cost significantly lower than commercial Pt/C and comparable to non-noble metal electrocatalysts.These Pt nanomembranes consist of highly distorted Pt nanocrystals and exhibit a heterogeneous elastic strain field,a characteristic rarely seen in conventional crystals.This unique feature results in significantly higher electrocatalytic efficiency than various forms of Pt electrocatalysts,including Pt/C,Pt foils,and numerous Pt singleatom or single-cluster catalysts.Our research offers a promising approach to develop highly efficient and cost-effective low-dimensional electrocatalysts for sustainable hydrogen production,potentially addressing the challenges posed by the climate crisis.展开更多
Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studi...Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studied, Kekulé distorted graphene has emerged as a promising material for valleytronics applications. Graphene can be artificially distorted to form the Kekulé structures rendering the valley-related interaction. In this work, we review the recent progress of research on Kekulé structures of graphene and focus on the modified electronic bands due to different Kekulé distortions as well as their effects on the transport properties of electrons. We systematically discuss how the valley-related interaction in the Kekulé structures was used to control and affect the valley transport including the valley generation, manipulation, and detection. This article summarizes the current challenges and prospects for further research on Kekulé distorted graphene and its potential applications in valleytronics.展开更多
The effects of carbon distribution on the microstructure and thermal conductivity of ductile iron were investigated in the present study.The microstructure of as-cast and quenched ductile iron were characterized by OM...The effects of carbon distribution on the microstructure and thermal conductivity of ductile iron were investigated in the present study.The microstructure of as-cast and quenched ductile iron were characterized by OM and SEM.Results showed that the microstructure of as-cast ductile iron was composed of spheroidal graphite,ferrite with the volume of 80%,and a small amount of pearlite,and quenched ductile iron was composed of spheroidal graphite,coarse/fine acicular martensite(α_(M)phase)and high-carbon retained austenite(γphase).The volume fraction of retained austensite and its carbon content for direct quenched ductile iron and tepmered ductile iron were quantitatively analysed by XRD.Results revealed that carbon atoms diffused fromα_(M)phase toγphase during tempering at low temperatures,which resulted in carbon content in retainedγphase increasing from 1.2 wt%for the direct quenched sample to about 1.9 wt%for the tempered samples.Consequently,the lattice distortion was significantly reduced and gave rise to an increase of thermal conductivity for ductile iron.展开更多
Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c...Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c. HEAs is generally low, significantly limiting their practical applications. Recently, the alloying of W has been evidenced to be able to remarkably improve the mechanical properties of f.c.c. HEAs and is becoming a hot topic in the community of HEAs. To date, when W is introduced, multiple strengthening mechanisms, including solid-solution strengthening, precipitation strengthening (μphase,σphase, and b.c.c. phase), and grain-refinement strengthening, have been discovered to be activated or enhanced. Apart from mechanical properties, the addition of W improves corrosion resistance as W helps to form a dense WO_(3) film on the alloy surface. Until now, despite the extensive studies in the literature, there is no available review paper focusing on the W doping of the f.c.c. HEAs. In that context, the effects of W doping on f.c.c. HEAs were reviewed in this work from three aspects, i.e., microstructure,mechanical property, and corrosion resistance. We expect this work can advance the application of the W alloying strategy in the f.c.c. HEAs.展开更多
Realizing efficient charge separation and directional transfer is a challenge for single-component semiconductors.The spatial electric field generated by dipole moment could promote charge separation.Here,three-dimens...Realizing efficient charge separation and directional transfer is a challenge for single-component semiconductors.The spatial electric field generated by dipole moment could promote charge separation.Here,three-dimensional hierarchical Cu Co_(2)S_(4)microspheres with lattice distortion were prepared,and lattice distortion was modulated by changing feed Co/Cu molar ratios in synthesis.Cu Co_(2)S_(4)showed asymmetric crystal structure,leading to generation of dipole moment.The charge separation efficiency of Cu Co_(2)S_(4)was related to lattice distortion,and lattice expansion was in favor for charge separation.The Cu Co_(2)S_(4)with feed Cu/Co molar ratio of 1:4 (CCS-4) showed the maximum lattice expansion and exhibited the highest photocatalytic activity,which was attributable to the highest charge separation efficiency and the largest specific surface area.CCS-4 can remove 95.4%of tetracycline hydrochloride within 40 min photocatalysis,and effectively improve the biodegradability of pharmaceutical wastewater.Importantly,this study provides a new vision for constructing single-component photocatalysts with high photocatalytic performance.展开更多
The electron paramagnetic spectra of trigonal Mn^(2+) centers in[Co(H_(2)O)_(6)]SiF6,[Co(H_(2)O)_(6)]SnF6,and[Co(H_(2)O)_(6)]PtCl6 crystals were studied on the basis of the complete energy matrices for a d5 configurat...The electron paramagnetic spectra of trigonal Mn^(2+) centers in[Co(H_(2)O)_(6)]SiF6,[Co(H_(2)O)_(6)]SnF6,and[Co(H_(2)O)_(6)]PtCl6 crystals were studied on the basis of the complete energy matrices for a d5 configuration ion in a trigonal ligand field.When Mn^(2+) is doped in the[Co(H_(2)O)_(6)]SiF6,[Co(H_(2)O)_(6)]SnF6,and[Co(H_(2)O)_(6)]PtCl6 crystals crystals,there is a similar local distortion.The experimental results show that the local lattice structure around a trigonal Mn^(2+) center has an elongation distortion along the crystalline C3 axis.From the EPR calculation,the local lattice structure parameters R=2.278A,θ=52.6406? for[Co(H_(2)O)_(6)]SiF6,R=2.280,θ=52.4936° for[Co(H_(2)O)_(6)]SnF6 and R=2.244A,θ=53.0616? for[Co(H_(2)O)_(6)]PtCl6 were determined.展开更多
Charge density wave(CDW)is a phenomenon that occurs in materials,accompanied by changes in their intrinsic electronic properties.The study of CDW and its modulation in materials holds tremendous significance in materi...Charge density wave(CDW)is a phenomenon that occurs in materials,accompanied by changes in their intrinsic electronic properties.The study of CDW and its modulation in materials holds tremendous significance in materials research,as it provides a unique approach to controlling the electronic properties of materials.TiSe_(2) is a typical layered material with a CDW phase at low temperatures.Through V substitution for Ti in TiSe_(2),we tuned the carrier concentration in V_(x)Ti_(1-x)Se_(2) to study how its electronic structures evolve.Angle-resolved photoemission spectroscopy(ARPES)shows that the band-folding effect is sustained with the doping level up to 10%,indicating the persistence of the CDW phase,even though the band structure is strikingly different from that of the parent compound TiSe_(2).Though CDW can induce the band fold effect with a driving force from the perspective of electronic systems,our studies suggest that this behavior could be maintained by lattice distortion of the CDW phase,even if band structures deviate from the electron-driven CDW scenario.Our work provides a constraint for understanding the CDW mechanism in TiSe_(2),and highlights the role of lattice distortion in the band-folding effect.展开更多
The primary purpose of this work is to optimize the thermophysical properties of rare-earth tan-talate ceramics using the high-entropy effect.Here,the high-entropy rare-earth tantalate ceramic(Y_(0.1)Nd_(0.1)Sm_(0.1)G...The primary purpose of this work is to optimize the thermophysical properties of rare-earth tan-talate ceramics using the high-entropy effect.Here,the high-entropy rare-earth tantalate ceramic(Y_(0.1)Nd_(0.1)Sm_(0.1)Gd_(0.1)Dy_(0.1)Ho_(0.1)Er_(0.1)Tm_(0.1)Yb_(0.1)Lu_(0.1))TaO_(4)((10RE_(0.1))TaO_(4))is synthesized successfully.The lat-tice distortion and oxygen vacancy concentration are characterized firstly in the rare-earth tantalates.Notably,compared with single rare-earth tantalates,the thermal conductivity of(10RE_(0.1))TaO_(4) is reduced by 16%-45%at 100℃ and 22%-45%at 800℃,and it also presents lower phonon thermal conductivity in the entire temperature range from 100 to 1200℃.The phonon thermal conductivity(1.0-2.2 W m^(-1) K^(-1),100-1200℃)of(10RE_(0.1))TaO_(4) is lower than that of the currently reported high-entropy four-,five-and six-component rare-earth tantalates.This is the result of scattering by the ferroelastic domain,lattice distortion associated with size and mass disorder,and point defects,which target low-,mid-and high-frequency phonons.Furthermore,(10RE_(0.1))TaO_(4),as an improved candidate for thermal barrier coatings materials(TBCs),has a higher thermal expansion coefficient(10.5×10^(-6)K^(-1) at 1400℃),lower Young’s modulus(123 GPa)and better high-temperature phase stability than that of single rare-earth tantalates.展开更多
For oxides,controlling the concentration of oxygen vacancy is a useful way to optimize their functional properties.However,when it comes to the field of negative thermal expansion(NTE),much less attention has been pai...For oxides,controlling the concentration of oxygen vacancy is a useful way to optimize their functional properties.However,when it comes to the field of negative thermal expansion(NTE),much less attention has been paid to the effect of oxygen vacancy on NTE,though oxide-typed NTE materials account for more than 40%of the total NTE materials.Here,we report that the linear coefficient of thermal expansion at 250–350 K of copper pyrophosphate(i.e.,Cu_(2)P_(2)O_(7))can be significantly improved from–13.88 to–36.60 ppm/K when the synthesis temperature is raised from 1073 to 1373 K.The combined study including X-ray absorption near edge structure,neutron powder diffraction,and X-ray diffraction has confirmed the selective vacancies in the O1 site for low-temperature synthesized samples,which suppress both the phase-transition and framework-structure driven NTE simultaneously.Our result proposes a new approach for optimizing the NTE effect of oxides.展开更多
Glycerol oxidation reaction(GOR)coupled with hydrogen generation simultaneously is a promising strategy for developing sustainable energy conversion technologies,but the complexity of glycerol oxidation products and t...Glycerol oxidation reaction(GOR)coupled with hydrogen generation simultaneously is a promising strategy for developing sustainable energy conversion technologies,but the complexity of glycerol oxidation products and the high coupling hydrogen evolution potential limit its wide application.In this paper,a self-supported high-entropy selenide electrode can be fabricated via a simple hydrothermal process.Then,the prepared electrode as an advanced catalyst displays optimal catalytic activity(1.20 V at 10 mA·cm^(−2))and high selectivity for the formation of formate in GOR.The results show that the lattice distortion effect of high entropy materials composed of multiple elements is mainly responsible for the greatly improved catalytic activity and selectivity for GOR.Moreover,an advanced alkali-acid hybrid electrolytic cell was assembled that enables efficient energy-saving hydrogen generation and GOR simultaneously.Herein,the electrolyzer requires only 0.5 V applied voltage to reach 10 mA·cm^(−2) for hydrogen generation and maintains long-term operation stability.展开更多
Molybdenum(Mo)has been recognized as an essential alloying element of the MP35N(Co_(35.4)Cr_(22.9)Ni_(35.5)Mo_(6.2),at.%)superalloy for enhancing strength and corrosion resistance.However,a full understanding of the a...Molybdenum(Mo)has been recognized as an essential alloying element of the MP35N(Co_(35.4)Cr_(22.9)Ni_(35.5)Mo_(6.2),at.%)superalloy for enhancing strength and corrosion resistance.However,a full understanding of the addition of Mo on microstructure and mechanical properties of the Mo-free parent alloy is lacking.In this work,we consider five(Co_(37.7)Cr_(24.4)Ni_(37.9))_(100-x)Mo_(x)(x=0,0.7,2.0,3.2,and 6.2)alloys,and reveal that yield/tensile strength and ductility are continuously increased for these alloys with increasing Mo content while a single-phase face-centered cubic structure remains unchanged.It is found that strong solid solution strengthening(SSS)is a main domain to the improved yield strength,whereas grain boundaries are found to soften by the Mo addition.The first-principles calculations demonstrate that a severe local lattice distortion contributes to the enhanced SSS,and the grain boundary softening effect is mostly associated with the decreased shear modulus.Both first-principles calculations and scanning transmission electron microscopy observations reveal that the stacking fault energy(SFE)reduces by the Mo addition.The calculated SFE value decreases from 0.4 mJ/m^(2) to-11.8 mJ/m^(2) at 0 K as Mo content increases from 0 at.%to 6.2 at.%,and experimentally measured values of SFE at room temperature for both samples are about 18 mJ/m^(2) and 9 mJ/m^(2),respectively.The reduction of SFE promoted the generation of stacking faults and deformation twins,which sustain a high strain hardening rate,thus postponing necking instability and enhancing tensile strength and elongation.展开更多
High-entropy diborides(HEBs)have attracted extensive research due to their potential ultra-high hardness.In the present work,the effects of transition metals(TM)on lattice parameters,electron work function(EWF),bondin...High-entropy diborides(HEBs)have attracted extensive research due to their potential ultra-high hardness.In the present work,the effects of transition metals(TM)on lattice parameters,electron work function(EWF),bonding charge density,and hardness of HEBs are comprehensively investigated by the first-principles calculations,including(TiZrHfNbTa)B_(2),(TiZrHfNbMo)B_(2),(TiZrHfTaMo)B_(2),(TiZrNbTaMo)B_(2),and(TiHfNbTaMo)B_(2).It is revealed that the disordered TM atoms result in a severe local lattice distortion and the formation of weak spots.In view of bonding charge density,it is understood that the degree of electron contribution of TM atoms directly affects the bonding strength of the metallic layer,contributing to the optimized hardness of HEBs.Moreover,the proposed power-law-scaled relationship integrating the EWF and the grain size yields an excellent agreement between our predicted results and those reported experimental ones.It is found that the HEBs exhibit relatively high hardness which is higher than those of single transition metal diborides.In particular,the hardness of(TiZrNbTaMo)B_(2)and(TiHfNbTaMo)B_(2)can be as high as29.15 and 28.02 GPa,respectively.This work provides a rapid strategy to discover/design advanced HEBs efficiently,supported by the coupling hardening mechanisms of solid solution and grain refinement based on the atomic and electronic interactions.展开更多
Herein,we trained machine learning(ML)model to quickly and accurately conduct the strength prediction of refractory high entropy alloys(RHEAs)matrix.Gradient Boosting(GB)regression model shows an outstanding performan...Herein,we trained machine learning(ML)model to quickly and accurately conduct the strength prediction of refractory high entropy alloys(RHEAs)matrix.Gradient Boosting(GB)regression model shows an outstanding performance against other ML models.In addition,the heat of fusion and atomic size difference is shown to be paramount to the strength of the high entropy alloys(HEAs)matrix.In addition,we discussed the contribution of each feature to the solid solution strengthening(SSS)of HE As.The excellent predictive accuracy shows that the GB model can be efficient and reliable for the design of RHEAs with desired strength.展开更多
The effect of Mo additions on the microstructures and mechanical properties of CoCrNi alloys was investigated,meanwhile,ab initio calculations are performed to quantitatively evaluate the lattice distortion and stacki...The effect of Mo additions on the microstructures and mechanical properties of CoCrNi alloys was investigated,meanwhile,ab initio calculations are performed to quantitatively evaluate the lattice distortion and stacking fault energy(SFE).The yield strength,ultimate tensile strength,and elongation of(CoCrNi)_(97)Mo_(3)alloy are 475 MPa,983 MPa and 69%,respectively.The yield strength is increased by~30%and high ductility is maintained,in comparison with CoCrNi alloy.Besides the nano-twins and dislocations,the higher density of stacking faults is induced during the tensile deformation for(CoCrNi)_(97)Mo_(3)alloy.Ab initio calculation results indicate the mean square atomic displacement(MSAD)and SFE value of(CoCrNi)_(97)Mo_(3)alloy is 42.6 pm^(2)and-40.4 mJ/m^(2)at 0 K,respectively.The relationship between mechanical properties and MSAD,SFE for various multiple principal element alloys is discussed.展开更多
基金supported by the Natural Science Foundation of Anhui Province(Grant No.2008085ME125)University Natural Science Research Project of Anhui Province(Grant Nos.KJ2020A0268 and KJ2020A0270).
文摘High-entropy oxides(HEOs)have gained great attention as an emerging kind of highperformance anode materials for lithium-ion batteries(LIBs)due to the entropy stabilization and multi-principal synergistic effect.Herein,the porous perovskite-type RE(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3)(RE(=La,Sm,and Gd)is the abbreviation of rare earth)HEOs were successfully synthesized by a solution combustion synthesis(SCS)method.Owing to the synergistic effect of lattice distortion and oxygen vacancies(Ov),the Gd(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3) electrode exhibits superior high-rate lithium-ion storage performance and excellent cycling stability.A reversible capacity of 403 mAh·g^(-1) at a current rate of 0.2 A·g^(-1) after 500 cycles and a superior high-rate capacity of 394 mAh·g^(-1)even at 1.0 A·g^(-1)after 500 cycles are achieved.Meanwhile,the Gd(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))O_(3) electrode also exhibits a pronounced pseudo-capacitive behavior,contributing to an additional capacity.By adjusting and balancing the lattice distortion and oxygen vacancies of the electrode materials,the lithium-ion storage performance can be further regulated.
基金supported by the Young Scholars Program of Shandong University and the National Natural Science Foundation of China(22275116).
文摘Lattice distortion represents the fundamental factor of crystalline materials and contributes significantly to structural-related properties.Herein,we discover an unexpected temperature-induced lattice distortion in CuGeO_(3) nanocrystals,resulting in color changes of CuGeO_(3).The structural distortions in CuGeO_(3) nanocrystals are characterized by Rietveld analysis in detail,where its cell parameter b and cell volume reveal first decrease and then increase characteristics and correspond well with the XRD patterns and Raman spectra.Besides,both the experimental characterizations and theoretical calculations confirm that the optical and band structural changes mainly arise from the twisted octahedral field of[CuO_(6)],where the lattice distortions regulate the crystal field splitting energy of[CuO_(6)]and account for its changed d-d transition.Furthermore,tetracycline photodegradation is employed as an example to evaluate the effect of lattice distortion on photocatalytic performance,which also highlights the importance of modulating lattice distortion in photocatalysis.This work provides an approach to simply regulate the lattice distortion for nanorods by manipulating calcination temperatures.
基金supported by the National Natural Science Foundation of China(Grant Nos.52101233 and52071279)the Hebei Natural Science Foundation(Grant No.E2022203010)+1 种基金the China Postdoctoral Science Foundation(Grant No.2022M712685)the Innovation Capability Improvement Project of Hebei Province(Grant No.22567605H)。
文摘Out-of-plane weak ferromagnetic(OWFM)spin arrangements with topological properties can realize a series of interesting physical properties.However,this spin structure tends to exist at low temperatures.The OWFM structure can also be induced at room temperature by hydrostatic pressure,whereas this isotropic approach tends to form helical AFM structures.We report the OWFM spin arrangement in single crystal Mn_(3)Sn by an anisotropic strategy of high-stressconstrained compression deformation at room temperature.Both experimental and theoretical simulation results show that the alignment of the OWFM spin structure is due to the distortion of the atomic scale caused by the strain energy during deformation.The OWFM spin arrangement can significantly change the magnetic property of Mn_(3)Sn.As a result,the remanent magnetization M_(r)for the deformed sample(0.056μ_(B)/f.u.)is about eleven times that for the pre-deformed sample(0.005μ_(B)/f.u.),and the coercivity(H_(c))increases from 0 k Oe(pre-deformed sample)to 6.02 k Oe(deformed sample).Our findings provide a way to generate the OWFM spin structure at room temperature and may give fresh ideas for creating antiferromagnetic materials with excellent physical properties.
基金financially supported by the National Natural Science Foundation of China(No.21905033)Department of Science and Technology of Sichuan Province(No.2019YJ0503)State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(No.2020P4FZG02A)。
文摘Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2)/o-CoSe_(2)as the oxygen electrode of lithium-oxygen batteries(LOBs)to improve its cycle stability.The heterogeneous interface inside c-CoSe_(2)/o-CoSe_(2)leads to an increase in the covalence bonds between Co and Se ions,which greatly enhances the robustness of the crystal lattice,thereby improving the stability of the catalyst.In addition,the strong interaction between the mixed phases is favorable for adjusting the electron density around the active sites and boosting oxygen electrode kinetics.Moreover,the epitaxial growth of o-CoSe_(2)on c-CoSe_(2)will cause abundant heterogeneous interfaces and slight lattice distortion along the interfaces,thereby providing sufficient catalytic reaction sites.The DFT calculation results show that the optimized adsorption of intermediates at the heterogeneous interface plays an important role in boosting oxygen electrode reactions and improving the electrochemical performance of LOBs.The experimental results show that LOBs with the c-CoSe_(2)/o-CoSe_(2)electrodes exhibit outstanding performance,including large specific capacity of about 23,878 m A h g^(-1),high coulombic efficiency of up to 93.66%,and excellent stability of over 176 cycles(1410 h).
基金financially supported by the National Key Research and Development Program of China(No.2017YFB0702003)the National Science Foundation of China(Nos.12002341,11790292 and 11672316)+4 种基金the NSFC Basic Science Center Program for“Multiscale Problems in Nonlinear Mechanics”(No.11988102)the Strategic Priority Research Program(Nos.XDB22040302 and XDB22040303)the Key Research Program of Frontier Sciences(No.QYZDJSSWJSC011)the Science Challenge Project(No.TZ2016001)the Zhejiang Provincial Natural Science Foundation(No.LGG21E010005)。
文摘Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ranges.However,little attention has been paid to the evolution of lattice distortion with temperature decreasing and its effects on deformation behavior and magnetic state transition.In this work,we carry out in situ synchrotron radiation based X-ray powder diffraction(SR-XRD)experiments from 293 to 123 K aiming for determining lattice distortion evolutions of Cr Co Ni MEA,Cr Fe Co Ni and Cr Mn Fe Co Ni HEAs.Magnetic measurements at corresponding low temperatures and cryogenic ranges are further conducted.The in situ SR-XRD results demonstrate a general reduction of lattice distortion magnitude with temperature decreasing,which shows a similar tendency with that of reported stacking fault energy(SFE)values.It is thus suggested that lattice distortion reduction possibly makes a critical contribution to deformation mechanism transition.The magnetic measurement results show a clear ferromagnetic transition of Cr Fe Co Ni HEA when temperature is below 173 K.While,no obvious magnetic state transition is observed for Cr Co Ni MEA and Cr Mn Fe Co Ni HEA.The present findings on lattice distortion evolutions will pave the way for designing targeted HEAs with particular properties.
基金The research of YY is supported by the Research Grant Council(RGC)through the General Research Fund(GRF)with the grant number N_CityU 109/21,CityU11213118 and CityU11209317.
文摘Hydrogen production through hydrogen evolution reaction(HER)offers a promising solution to combat climate change by replacing fossil fuels with clean energy sources.However,the widespread adoption of efficient electrocatalysts,such as platinum(Pt),has been hindered by their high cost.In this study,we developed an easy-to-implement method to create ultrathin Pt nanomembranes,which catalyze HER at a cost significantly lower than commercial Pt/C and comparable to non-noble metal electrocatalysts.These Pt nanomembranes consist of highly distorted Pt nanocrystals and exhibit a heterogeneous elastic strain field,a characteristic rarely seen in conventional crystals.This unique feature results in significantly higher electrocatalytic efficiency than various forms of Pt electrocatalysts,including Pt/C,Pt foils,and numerous Pt singleatom or single-cluster catalysts.Our research offers a promising approach to develop highly efficient and cost-effective low-dimensional electrocatalysts for sustainable hydrogen production,potentially addressing the challenges posed by the climate crisis.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12174051 and 12304069)。
文摘Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studied, Kekulé distorted graphene has emerged as a promising material for valleytronics applications. Graphene can be artificially distorted to form the Kekulé structures rendering the valley-related interaction. In this work, we review the recent progress of research on Kekulé structures of graphene and focus on the modified electronic bands due to different Kekulé distortions as well as their effects on the transport properties of electrons. We systematically discuss how the valley-related interaction in the Kekulé structures was used to control and affect the valley transport including the valley generation, manipulation, and detection. This article summarizes the current challenges and prospects for further research on Kekulé distorted graphene and its potential applications in valleytronics.
基金Funded by China Postdoctoral Science Foundation(Nos.2019M653703 and 2020T130523)Xi’an University of Technology Youth Nova Fund(No.101-451320005)。
文摘The effects of carbon distribution on the microstructure and thermal conductivity of ductile iron were investigated in the present study.The microstructure of as-cast and quenched ductile iron were characterized by OM and SEM.Results showed that the microstructure of as-cast ductile iron was composed of spheroidal graphite,ferrite with the volume of 80%,and a small amount of pearlite,and quenched ductile iron was composed of spheroidal graphite,coarse/fine acicular martensite(α_(M)phase)and high-carbon retained austenite(γphase).The volume fraction of retained austensite and its carbon content for direct quenched ductile iron and tepmered ductile iron were quantitatively analysed by XRD.Results revealed that carbon atoms diffused fromα_(M)phase toγphase during tempering at low temperatures,which resulted in carbon content in retainedγphase increasing from 1.2 wt%for the direct quenched sample to about 1.9 wt%for the tempered samples.Consequently,the lattice distortion was significantly reduced and gave rise to an increase of thermal conductivity for ductile iron.
基金financially supported by the National Key R&D Program of China (No.2021YFA1200203)the National Natural Science Foundation of China (Nos.51922026 and 51975111)+1 种基金the Fundamental Research Funds for the Central Universities (No.N2202015,N2002005,and N2105001)the 111 Project of China (No.BP0719037 and B20029)。
文摘Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c. HEAs is generally low, significantly limiting their practical applications. Recently, the alloying of W has been evidenced to be able to remarkably improve the mechanical properties of f.c.c. HEAs and is becoming a hot topic in the community of HEAs. To date, when W is introduced, multiple strengthening mechanisms, including solid-solution strengthening, precipitation strengthening (μphase,σphase, and b.c.c. phase), and grain-refinement strengthening, have been discovered to be activated or enhanced. Apart from mechanical properties, the addition of W improves corrosion resistance as W helps to form a dense WO_(3) film on the alloy surface. Until now, despite the extensive studies in the literature, there is no available review paper focusing on the W doping of the f.c.c. HEAs. In that context, the effects of W doping on f.c.c. HEAs were reviewed in this work from three aspects, i.e., microstructure,mechanical property, and corrosion resistance. We expect this work can advance the application of the W alloying strategy in the f.c.c. HEAs.
基金financially supported by the National Natural Science Foundation of China (Nos. 51978324, 51720105001, 51938007)Natural Science Foundation of Jiangxi Province (Nos. 20213BCJL22053, 20192ACBL20043, 20192ACBL21047)+1 种基金Natural Science Foundation of Jiangxi Province, China (No. 20212BAB204045)Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle (Nanchang Hangkong University) (No. ES202002077)。
文摘Realizing efficient charge separation and directional transfer is a challenge for single-component semiconductors.The spatial electric field generated by dipole moment could promote charge separation.Here,three-dimensional hierarchical Cu Co_(2)S_(4)microspheres with lattice distortion were prepared,and lattice distortion was modulated by changing feed Co/Cu molar ratios in synthesis.Cu Co_(2)S_(4)showed asymmetric crystal structure,leading to generation of dipole moment.The charge separation efficiency of Cu Co_(2)S_(4)was related to lattice distortion,and lattice expansion was in favor for charge separation.The Cu Co_(2)S_(4)with feed Cu/Co molar ratio of 1:4 (CCS-4) showed the maximum lattice expansion and exhibited the highest photocatalytic activity,which was attributable to the highest charge separation efficiency and the largest specific surface area.CCS-4 can remove 95.4%of tetracycline hydrochloride within 40 min photocatalysis,and effectively improve the biodegradability of pharmaceutical wastewater.Importantly,this study provides a new vision for constructing single-component photocatalysts with high photocatalytic performance.
基金Funded by the National Natural Science Foundation of China (Nos. 11804285 and 61601384)。
文摘The electron paramagnetic spectra of trigonal Mn^(2+) centers in[Co(H_(2)O)_(6)]SiF6,[Co(H_(2)O)_(6)]SnF6,and[Co(H_(2)O)_(6)]PtCl6 crystals were studied on the basis of the complete energy matrices for a d5 configuration ion in a trigonal ligand field.When Mn^(2+) is doped in the[Co(H_(2)O)_(6)]SiF6,[Co(H_(2)O)_(6)]SnF6,and[Co(H_(2)O)_(6)]PtCl6 crystals crystals,there is a similar local distortion.The experimental results show that the local lattice structure around a trigonal Mn^(2+) center has an elongation distortion along the crystalline C3 axis.From the EPR calculation,the local lattice structure parameters R=2.278A,θ=52.6406? for[Co(H_(2)O)_(6)]SiF6,R=2.280,θ=52.4936° for[Co(H_(2)O)_(6)]SnF6 and R=2.244A,θ=53.0616? for[Co(H_(2)O)_(6)]PtCl6 were determined.
基金support from the National Key R&D Program of China(No.2017YFA0402901)the National Natural Science Foundation of China(Nos.U2032153,21727801,and 11621063)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB25000000)the International Partnership Program of Chinese Academy of Sciences(CAS)(No.211134KYSB20190063)the Collaborative Innovation Program of Hefei Science Center of CAS(No.2019HSC-CIP007).
文摘Charge density wave(CDW)is a phenomenon that occurs in materials,accompanied by changes in their intrinsic electronic properties.The study of CDW and its modulation in materials holds tremendous significance in materials research,as it provides a unique approach to controlling the electronic properties of materials.TiSe_(2) is a typical layered material with a CDW phase at low temperatures.Through V substitution for Ti in TiSe_(2),we tuned the carrier concentration in V_(x)Ti_(1-x)Se_(2) to study how its electronic structures evolve.Angle-resolved photoemission spectroscopy(ARPES)shows that the band-folding effect is sustained with the doping level up to 10%,indicating the persistence of the CDW phase,even though the band structure is strikingly different from that of the parent compound TiSe_(2).Though CDW can induce the band fold effect with a driving force from the perspective of electronic systems,our studies suggest that this behavior could be maintained by lattice distortion of the CDW phase,even if band structures deviate from the electron-driven CDW scenario.Our work provides a constraint for understanding the CDW mechanism in TiSe_(2),and highlights the role of lattice distortion in the band-folding effect.
基金financially supported by the Rare and Precious Metals Material Genetic Engineering Project of Yunnan Province(Nos.202102AB080019-1 and 202002AB080001-1)the Yun-nan Fundamental Research Projects(Nos.202101AW070011 and 202101BE070001-015).
文摘The primary purpose of this work is to optimize the thermophysical properties of rare-earth tan-talate ceramics using the high-entropy effect.Here,the high-entropy rare-earth tantalate ceramic(Y_(0.1)Nd_(0.1)Sm_(0.1)Gd_(0.1)Dy_(0.1)Ho_(0.1)Er_(0.1)Tm_(0.1)Yb_(0.1)Lu_(0.1))TaO_(4)((10RE_(0.1))TaO_(4))is synthesized successfully.The lat-tice distortion and oxygen vacancy concentration are characterized firstly in the rare-earth tantalates.Notably,compared with single rare-earth tantalates,the thermal conductivity of(10RE_(0.1))TaO_(4) is reduced by 16%-45%at 100℃ and 22%-45%at 800℃,and it also presents lower phonon thermal conductivity in the entire temperature range from 100 to 1200℃.The phonon thermal conductivity(1.0-2.2 W m^(-1) K^(-1),100-1200℃)of(10RE_(0.1))TaO_(4) is lower than that of the currently reported high-entropy four-,five-and six-component rare-earth tantalates.This is the result of scattering by the ferroelastic domain,lattice distortion associated with size and mass disorder,and point defects,which target low-,mid-and high-frequency phonons.Furthermore,(10RE_(0.1))TaO_(4),as an improved candidate for thermal barrier coatings materials(TBCs),has a higher thermal expansion coefficient(10.5×10^(-6)K^(-1) at 1400℃),lower Young’s modulus(123 GPa)and better high-temperature phase stability than that of single rare-earth tantalates.
基金supported by the National Natural Foundation of China(No.52171146 and No.U1932127)Natural Science Foundation of Anhui Province(No.2108085ME145)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS)(No.QYZDB-SSW-SLH015)。
文摘For oxides,controlling the concentration of oxygen vacancy is a useful way to optimize their functional properties.However,when it comes to the field of negative thermal expansion(NTE),much less attention has been paid to the effect of oxygen vacancy on NTE,though oxide-typed NTE materials account for more than 40%of the total NTE materials.Here,we report that the linear coefficient of thermal expansion at 250–350 K of copper pyrophosphate(i.e.,Cu_(2)P_(2)O_(7))can be significantly improved from–13.88 to–36.60 ppm/K when the synthesis temperature is raised from 1073 to 1373 K.The combined study including X-ray absorption near edge structure,neutron powder diffraction,and X-ray diffraction has confirmed the selective vacancies in the O1 site for low-temperature synthesized samples,which suppress both the phase-transition and framework-structure driven NTE simultaneously.Our result proposes a new approach for optimizing the NTE effect of oxides.
基金supported by the Key Projects of Intergovernmental International Cooperation in Key R&D Programs of the Ministry of Science and Technology of China(No.2021YFE0115800)the National Science Funding Committee of China(No.U20A20250)the Science and Technology Committee of Shaanxi Province(No.2020JZ-42).
文摘Glycerol oxidation reaction(GOR)coupled with hydrogen generation simultaneously is a promising strategy for developing sustainable energy conversion technologies,but the complexity of glycerol oxidation products and the high coupling hydrogen evolution potential limit its wide application.In this paper,a self-supported high-entropy selenide electrode can be fabricated via a simple hydrothermal process.Then,the prepared electrode as an advanced catalyst displays optimal catalytic activity(1.20 V at 10 mA·cm^(−2))and high selectivity for the formation of formate in GOR.The results show that the lattice distortion effect of high entropy materials composed of multiple elements is mainly responsible for the greatly improved catalytic activity and selectivity for GOR.Moreover,an advanced alkali-acid hybrid electrolytic cell was assembled that enables efficient energy-saving hydrogen generation and GOR simultaneously.Herein,the electrolyzer requires only 0.5 V applied voltage to reach 10 mA·cm^(−2) for hydrogen generation and maintains long-term operation stability.
基金financially supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.52001120)the Hunan Provincial National Science Fund for Distin-guished Young Scholars(No.2022JJ10015)+2 种基金the State Key Labora-tory of Advanced Metals and Materials(No.2021-Z09)the Univer-sity of Science&Technology Beijing,China.X.Q.Li was supported by the Swedish Research Council(No.2020-03736)funded by the Swedish Research Council through grant agreement(No.2018-05973)。
文摘Molybdenum(Mo)has been recognized as an essential alloying element of the MP35N(Co_(35.4)Cr_(22.9)Ni_(35.5)Mo_(6.2),at.%)superalloy for enhancing strength and corrosion resistance.However,a full understanding of the addition of Mo on microstructure and mechanical properties of the Mo-free parent alloy is lacking.In this work,we consider five(Co_(37.7)Cr_(24.4)Ni_(37.9))_(100-x)Mo_(x)(x=0,0.7,2.0,3.2,and 6.2)alloys,and reveal that yield/tensile strength and ductility are continuously increased for these alloys with increasing Mo content while a single-phase face-centered cubic structure remains unchanged.It is found that strong solid solution strengthening(SSS)is a main domain to the improved yield strength,whereas grain boundaries are found to soften by the Mo addition.The first-principles calculations demonstrate that a severe local lattice distortion contributes to the enhanced SSS,and the grain boundary softening effect is mostly associated with the decreased shear modulus.Both first-principles calculations and scanning transmission electron microscopy observations reveal that the stacking fault energy(SFE)reduces by the Mo addition.The calculated SFE value decreases from 0.4 mJ/m^(2) to-11.8 mJ/m^(2) at 0 K as Mo content increases from 0 at.%to 6.2 at.%,and experimentally measured values of SFE at room temperature for both samples are about 18 mJ/m^(2) and 9 mJ/m^(2),respectively.The reduction of SFE promoted the generation of stacking faults and deformation twins,which sustain a high strain hardening rate,thus postponing necking instability and enhancing tensile strength and elongation.
基金financially supported by the Science Challenge Project(No.TZ 2018002)。
文摘High-entropy diborides(HEBs)have attracted extensive research due to their potential ultra-high hardness.In the present work,the effects of transition metals(TM)on lattice parameters,electron work function(EWF),bonding charge density,and hardness of HEBs are comprehensively investigated by the first-principles calculations,including(TiZrHfNbTa)B_(2),(TiZrHfNbMo)B_(2),(TiZrHfTaMo)B_(2),(TiZrNbTaMo)B_(2),and(TiHfNbTaMo)B_(2).It is revealed that the disordered TM atoms result in a severe local lattice distortion and the formation of weak spots.In view of bonding charge density,it is understood that the degree of electron contribution of TM atoms directly affects the bonding strength of the metallic layer,contributing to the optimized hardness of HEBs.Moreover,the proposed power-law-scaled relationship integrating the EWF and the grain size yields an excellent agreement between our predicted results and those reported experimental ones.It is found that the HEBs exhibit relatively high hardness which is higher than those of single transition metal diborides.In particular,the hardness of(TiZrNbTaMo)B_(2)and(TiHfNbTaMo)B_(2)can be as high as29.15 and 28.02 GPa,respectively.This work provides a rapid strategy to discover/design advanced HEBs efficiently,supported by the coupling hardening mechanisms of solid solution and grain refinement based on the atomic and electronic interactions.
基金financially supported by the National Natural Science Foundation of China(NSFC,52163019,22005131,52173169 and U20A20128)the support from the Postdoctoral Innovative Talents Support Program(BX2021117)+1 种基金China Postdoctoral Science Foundation(2021M700060)the Graduate Students Innovation Special Foundation of Jiangxi Province(YC2022-B009)。
基金supported by the Faculty Startup Fund in the New York State College of Ceramics at Alfred University。
文摘Herein,we trained machine learning(ML)model to quickly and accurately conduct the strength prediction of refractory high entropy alloys(RHEAs)matrix.Gradient Boosting(GB)regression model shows an outstanding performance against other ML models.In addition,the heat of fusion and atomic size difference is shown to be paramount to the strength of the high entropy alloys(HEAs)matrix.In addition,we discussed the contribution of each feature to the solid solution strengthening(SSS)of HE As.The excellent predictive accuracy shows that the GB model can be efficient and reliable for the design of RHEAs with desired strength.
基金supported financially by the National Natural Science Foundation of China(Nos.51701061 and 51601020)the Natural Science Foundation of Hebei Province(No.E2019202059)。
文摘The effect of Mo additions on the microstructures and mechanical properties of CoCrNi alloys was investigated,meanwhile,ab initio calculations are performed to quantitatively evaluate the lattice distortion and stacking fault energy(SFE).The yield strength,ultimate tensile strength,and elongation of(CoCrNi)_(97)Mo_(3)alloy are 475 MPa,983 MPa and 69%,respectively.The yield strength is increased by~30%and high ductility is maintained,in comparison with CoCrNi alloy.Besides the nano-twins and dislocations,the higher density of stacking faults is induced during the tensile deformation for(CoCrNi)_(97)Mo_(3)alloy.Ab initio calculation results indicate the mean square atomic displacement(MSAD)and SFE value of(CoCrNi)_(97)Mo_(3)alloy is 42.6 pm^(2)and-40.4 mJ/m^(2)at 0 K,respectively.The relationship between mechanical properties and MSAD,SFE for various multiple principal element alloys is discussed.
