La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation pr...La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.展开更多
ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn1...ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn12-type phase,excessively small single-domain grain size,and complex fabrication processes have hindered the achievement of high phase purity,uniform microstructure,and desirable extrinsic performance.In this study,we directly synthesized ThMn_(12)-type Sm_(0.8)Zr_(0.2)Fe_(11)SiB_(x)(x=0-0.2)ribbon magnets via boron doping combined with a one-step rapid solidification method.This approach not only simplifies the fabrication process but also enhances phase stability and achieves a uniform microstructure with high ThMn12-type phase purity.By optimizing the boron content and cooling rate,the resulting magnets exhibit a coercivity(H_(c))of 6222 Oe,a remanence(M_(r))of 80 emu/g,and a remanence ratio(M_(r)/M_(s))of 0.71.This work demonstrates a streamlined approach to producing high-performance ThMn12-type magnets and provides insights into their practical application potential.展开更多
Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by ...Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by using three-point bending tests and bending load-unloading tests.The biocompatibility was investigated by the adhesion,proliferation and the alkaline phosphatase(ALP)activity of mouse osteoblast-like cells(MC3T3-E1).The results showed that the bending modulus and bending yield strength first were increased and then decreased with the increase in Mo content,while the springback ratio exhibited an opposite trend to the bending modulus.With the increase in O content,the bending modulus remained almost constant,while the bending yield strength was increased.The springback ratio exhibited a similar trend to the bending yield strength.The in vitro biological experiments showed that the Ti-Mo-O alloys had excellent biocompatibility due to the formed stable oxide films on their surface.With the increase in O and Mo contents,the TiO_(2)-MoO_(2)oxide film became denser.Combining with mechanical compatibility and biocompatibility,the Ti-15Mo-0.2O and Ti-15Mo-0.3O alloys were more suitable for the biomedical application of spinal fixation device.展开更多
In science and technology,precision measurement of physical quantities is crucial,and the quantum Fisher information(QFI)plays a significant role in the study of quantum systems.In this work,we explore the dynamics of...In science and technology,precision measurement of physical quantities is crucial,and the quantum Fisher information(QFI)plays a significant role in the study of quantum systems.In this work,we explore the dynamics of QFI in a hybrid optomechanical system,which consists of a◇-type four-level atom interacting with a single-mode quantized field via a multi-photon process.We account for various sources of dissipation,including the decay rates of the atom,the cavity and the mechanical modes.Using an effective Hamiltonian,we analytically derive the explicit form of the state vector of the entire system via the time-dependent Schr?dinger equation.We then investigate the atomic QFI for the estimation precision of the decay rate of the mechanical oscillator.Furthermore,we examine how optomechanical and atom-field coupling strengths,dissipation parameters and multi-photon transition influence the dynamics of atomic QFI.Our numerical results suggest that the estimation precision of the decay rate of the mechanical oscillator can be controlled by these parameters.展开更多
03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hin...03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.展开更多
The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capac...The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.展开更多
Rare earth-Mg-Ni-based superlattice structure alloys have garnered recognition as promising materials for hydrogen storage.However,their application is impeded by suboptimal cycling longevity.The novel AB_(4)-type all...Rare earth-Mg-Ni-based superlattice structure alloys have garnered recognition as promising materials for hydrogen storage.However,their application is impeded by suboptimal cycling longevity.The novel AB_(4)-type alloy emerges as an attractive candidate,distinguished by its good structure stability,high rate capability,and long-term durability.Herein,we designed an AB_(4)-type La_(0.6)0Sm_(0.22)Mg_(0.18)Ni_(4.09)Al_(0.09)Mn_(0.10)alloy that manifests superior electrochemical performance.The obtained AB_(4)-type single-phase alloy delivers a high discharge capacity of 375.2 mAh·g^(-1)and features outstanding discharge ability at high rates,maintaining 121 mAh·g^(-1)even at a discharge rate of 6C.The excellent high-rate discharge performance can be attributed to its fast charge transfer and hydrogen diffusion kinetics.Moreover,the AB_(4)-type alloy maintains a capacity retention of 84.5%after 200 cycles and retains 55.7%of its capacity retention even after 500 cycles.This work provides a good alternative to hydrogen storage alloy with high power and long cycling durability performance for nickel metal hydride batteries.展开更多
Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a f...Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.展开更多
To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃...To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃reheating strategy.This method improves the surface properties of NFM without the need for additional coating layers,making it more efficient and suitable for large-scale applications.Pristine NFM(NFM-P)was first synthesized through a high-temperature solid-state method and then modified using this reheating approach(NFM-HT).This strategy significantly enhances air stability and electrochemical performance,yielding an initial discharge specific capacity of 151.46 mAh/g at 0.1C,with a remarkable capacity retention of 95.04%after 100 cycles at 0.5C.Additionally,a 1.7 Ah NFM‖HC(hard carbon)pouch cell demonstrates excellent long-term cycling stability(94.64%retention after 500 cycles at 1C),superior rate capability(86.48%retention at 9C),and strong low-temperature performance(77%retention at-25℃,continuing power supply at-40℃).Notably,even when overcharged to 8.29 V,the pouch cell remained safe without combustion or explosion.This reheating strategy,which eliminates the need for a coating layer,offers a simpler,more scalable solution for industrial production while maintaining outstanding electrochemical performance.These results pave the way for broader commercial adoption of NFM materials.展开更多
P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phas...P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.展开更多
The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate per...The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.展开更多
O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrolla...O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.展开更多
Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during ins...Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.展开更多
Additive manufacturing ofβ-type titanium alloy is expected to replace Ti-6Al-4V alloy in the field of orthopedic implantation because of their low elastic modulus,excellent corrosion resistance,and biocompatibility.A...Additive manufacturing ofβ-type titanium alloy is expected to replace Ti-6Al-4V alloy in the field of orthopedic implantation because of their low elastic modulus,excellent corrosion resistance,and biocompatibility.After briefly introducing the laser powder bed fusion(LPBF)process and physical phenomena,this paper reviews the recent progresses in LPBF-edβ-type Ti alloys.The strategies to strengthening and tougheningβ-type Ti alloys are critically reviewed.This is followed by the processing routes employed to achieve to low modulus for orthopedic applications,especially a new methodology for tailoring crystallographic orientation called multi-track coupled directional solidification.The effect of processing and compositions on performance metrics ofβ-type Ti alloys included corrosion behavior,and biocompatibility is reviewed.In the end,challenges in additive manufacturing ofβ-type Ti alloys in future are highlighted,with the aim to ensue clinical application of LPBF-edβ-type Ti alloys.展开更多
Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.H...Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.However,continuous voltage decay during cycling remains the primary obstacle for practical applications,which has yet to be fundamentally addressed.It is widely acknowledged that voltage decay originates from the irreversible migration of transition metal ions,which usually further exacerbates structural evolution and aggravates the irreversible oxygen redox reactions.Recently,constructing O2-type structure has been considered one of the most promising approaches for inhibiting voltage decay.In this review,the relationship between voltage decay and structural evolution is systematically elucidated.Strategies to suppress voltage decay are systematically summarized.Additionally,the design of O2-type structure and the corresponding mechanism of suppressing voltage decay are comprehensively discussed.Unfortunately,the reported O2-type LRLO cathodes still exhibit partially disordered structure with extended cycles.Herein,the factors that may cause the irreversible transition metal migrations in O2-type LRLO materials are also explored,while the perspectives and challenges for designing high-performance O2-type LRLO cathodes without voltage decay are proposed.展开更多
AB_(2)-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering...AB_(2)-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering their application is hydrogen induced amorphization(HIA),which leads to the irreversible hydrogen sorption process.The stability of the AB_2 Laves phase compounds,the structural properties,the hydrogenation properties and the controlling factors of HIA are discussed in this review.Comparing with other factors,the atomic radii ratio r_A/r_B is the most important one influencing the HIA.Multi-element substitution is an efficient way to suppress or limit HIA and may enable AB_2 compounds to be suitable for hydrogen storage.展开更多
The Na-deficient P3-type layered oxide cathode material usually experience complex in-plane Na^(+)/vacancy ordering rearrangement and undesirable P3-O3 phase transitions in the high-voltage region,leading to inferior ...The Na-deficient P3-type layered oxide cathode material usually experience complex in-plane Na^(+)/vacancy ordering rearrangement and undesirable P3-O3 phase transitions in the high-voltage region,leading to inferior cycling performance.Additionally,they exhibit unsatisfactory stability when exposed to water for extended periods.To address these challenges,we propose a Cu/Ti co-doped P3-type cathode material(Na_(0.67)Ni_(0.3)Cu_(0.03)Mn_(0.6)Ti_(0.07)O_(2)),which effectively mitigates Na^(+)/vacancy ordering and suppresses P3-O3 phase transitions at high voltages.As a result,the as-prepared sample exhibited outstanding cyclic performance,with 81.9%retention after 500 cycles within 2.5–4.15 V,and 75.7%retention after300 cycles within 2.5–4.25 V.Meanwhile,it demonstrates enhanced Na^(+)transport kinetics during desodiation/sodiation and reduced growth of charge transfer impedance(R_(ct))after various cycles.Furthermore,the sample showed superb stability against water,exhibiting no discernible degradation in structure,morphology,or electrochemical performance.This co-doping strategy provides new insights for innovative and prospective cathode materials.展开更多
Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage,as well as successful application as nickel-metal hydride batteries anodes.In this work,Y substitution was carried out to adjust t...Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage,as well as successful application as nickel-metal hydride batteries anodes.In this work,Y substitution was carried out to adjust the gaseous hydrogen storage properties of A_(2)B_(7)-type La_(0.7)Mg_(0.3)Ni_(3.5)alloys.The results indicate a multiphase structure in the alloys comprised of the main rhombohedral Gd_(2)Co_(7)and PuNi_(3)phases,with a small amount of CaCu_(5)phase.Moreover,the Y substitution results in higher abundance of the Gd_(2)Co_(7)phase.The alloy La_(0.42)Y_(0.28)Mg_(0.3)Ni_(3.5)exhibits a hydrogen storage cap acity of 1.55 wt%at 298 K and a desorption plateau pressure of 0.244 MPa.In addition,this alloy demonstrates a stable cycle life by a capacity retention of 94.2%after 50 cycles,with the main capacity degradation occurring during the initial 20 cycles.This work accentuates the potential of the La-Y-Mg-Ni-based superlattice alloys for applications in solid-state hydrogen storage.展开更多
A novel approach based on thermal diffusion was used to achieve controllable Mg content in A_(2)B_(7)-type La-Mg-Ni-based alloys.The formation mechanism of the A_(2)B_(7)-type phase as a result of the thermal diffusio...A novel approach based on thermal diffusion was used to achieve controllable Mg content in A_(2)B_(7)-type La-Mg-Ni-based alloys.The formation mechanism of the A_(2)B_(7)-type phase as a result of the thermal diffusion process and the effect of Mg content on hydrogen storage performance were investigated.X-ray diffraction(XRD)patterns and Rietveld refinement results showed that increased Mg transformed the LaNi_(5)phase in the La_(0.74)Sm_(0.03)Y_(0.23)Ni_(4.32)Al_(0.04)precursor alloy into a superlattice structure.Scanning electron microscopy(SEM)images showed that Mg was evenly distributed in the alloy bulk.Mg in the superlattice significantly inhibited the phase decomposition of the superlattice structure during the hydrogen absorption/desorption cycles.An A_(2)B_(7)-type La_(0.57)Sm_(0.02)Y_(0.18)Mg_(0.23)Ni_(3.38)Al_(0.03)alloy composed of Gd_(2)Co_(7)and Ce_(2)Ni_(7)phases was successfully synthesized.The pressure-composition isotherm profiles showed that the alloy had a hydrogen storage capacity as high as 1.73 wt%,with good cycling stability.After 50 cycles of hydrogen absorption/desorption,the alloy retained a hydrogen storage capacity of 1.45 wt%,with a capacity retention rate of up to 84.28%.The Mg thermal diffusion process thus provides a new approach for the controlled preparation of La-Mg-Ni-based alloys.展开更多
基金the financial support by the National Nat-ural Science Foundation of China(Nos.52201282,52071281,52371239)the China Postdoctoral Science Foundation(No.2023M742945)+4 种基金Hebei Provincial Postdoctoral Science Foundation(No.B2023003023)the Science Research Project of Hebei Education Department(No.BJK2022033)the Natural Science Foundation of Hebei Province(No.C2022203003)the Inner Mongolia Science and Technology Major Project(No.2020ZD0012)the Baotou Science and Technology Planning Project(No.XM2022BT09).
文摘La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFB3500300 and 2023YFB3507000)the Scientific Research Foundation of the High Education Institutions for Distinguished Young Scholars in Anhui Province(Grant No.2022AH020012)+1 种基金partially supported by the Innovation Project for Overseas Researcher in Anhui Province(Grant No.2022LCX004)the facilities at the Center of Free Electron Laser&High Magnetic Field(FEL&HMF)in Anhui University。
文摘ThMn_(12)-type iron-rich rare-earth permanent magnetic materials have garnered significant attention due to their exceptional intrinsic magnetic properties.However,challenges such as the metastable nature of the ThMn12-type phase,excessively small single-domain grain size,and complex fabrication processes have hindered the achievement of high phase purity,uniform microstructure,and desirable extrinsic performance.In this study,we directly synthesized ThMn_(12)-type Sm_(0.8)Zr_(0.2)Fe_(11)SiB_(x)(x=0-0.2)ribbon magnets via boron doping combined with a one-step rapid solidification method.This approach not only simplifies the fabrication process but also enhances phase stability and achieves a uniform microstructure with high ThMn12-type phase purity.By optimizing the boron content and cooling rate,the resulting magnets exhibit a coercivity(H_(c))of 6222 Oe,a remanence(M_(r))of 80 emu/g,and a remanence ratio(M_(r)/M_(s))of 0.71.This work demonstrates a streamlined approach to producing high-performance ThMn12-type magnets and provides insights into their practical application potential.
基金supported by the National Natural Science Foundation of China(Grant No.52071051)the(Key)Foundation of Xi'an Key Laboratory of High-Performance Titanium Alloy(No.NIN-HTL-2022-ZD01).
文摘Ti-Mo-O alloys were used to analyze the effect of Mo and O contents on the mechanical compatibility and biocompatibility.The bending modulus,bending yield strength and springback ratio of the alloys were evaluated by using three-point bending tests and bending load-unloading tests.The biocompatibility was investigated by the adhesion,proliferation and the alkaline phosphatase(ALP)activity of mouse osteoblast-like cells(MC3T3-E1).The results showed that the bending modulus and bending yield strength first were increased and then decreased with the increase in Mo content,while the springback ratio exhibited an opposite trend to the bending modulus.With the increase in O content,the bending modulus remained almost constant,while the bending yield strength was increased.The springback ratio exhibited a similar trend to the bending yield strength.The in vitro biological experiments showed that the Ti-Mo-O alloys had excellent biocompatibility due to the formed stable oxide films on their surface.With the increase in O and Mo contents,the TiO_(2)-MoO_(2)oxide film became denser.Combining with mechanical compatibility and biocompatibility,the Ti-15Mo-0.2O and Ti-15Mo-0.3O alloys were more suitable for the biomedical application of spinal fixation device.
文摘In science and technology,precision measurement of physical quantities is crucial,and the quantum Fisher information(QFI)plays a significant role in the study of quantum systems.In this work,we explore the dynamics of QFI in a hybrid optomechanical system,which consists of a◇-type four-level atom interacting with a single-mode quantized field via a multi-photon process.We account for various sources of dissipation,including the decay rates of the atom,the cavity and the mechanical modes.Using an effective Hamiltonian,we analytically derive the explicit form of the state vector of the entire system via the time-dependent Schr?dinger equation.We then investigate the atomic QFI for the estimation precision of the decay rate of the mechanical oscillator.Furthermore,we examine how optomechanical and atom-field coupling strengths,dissipation parameters and multi-photon transition influence the dynamics of atomic QFI.Our numerical results suggest that the estimation precision of the decay rate of the mechanical oscillator can be controlled by these parameters.
基金supported by the Science and technology plan project of Yulin(2023-CXY-193)the Project funded by Shaanxi Postdoctoral Science Foundation(2023BSHEDZZ274)+2 种基金the Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0588,Z20210201)the Science and technology plan project of Beilin(GX2319)the Science and technology plan project of Ankang(AK2023-GY-08)。
文摘03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.
基金financially supported by National Key Research and Development Program of China(No.2022YFE0202400)the National Natural Science Foundation of China(No.22379103)+2 种基金Natural Science Foundation of Guangdong Province of China(No.2021A1515010388)the Science and Technology Projects of Suzhou City(No.SYC2022043)the Qing Lan Project of Jiangsu Province(2022)。
文摘The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.
基金supported by the Natural Science Foundation of China(Nos.52201282 and 52371239)the Natural Science Foundation of Hebei Province(No.E2024203037)+1 种基金the Basic Innovation Research Project in Yanshan University(2022LGZD004)Baotou Science and Technology Planning Project(No.XM2022BT09).
文摘Rare earth-Mg-Ni-based superlattice structure alloys have garnered recognition as promising materials for hydrogen storage.However,their application is impeded by suboptimal cycling longevity.The novel AB_(4)-type alloy emerges as an attractive candidate,distinguished by its good structure stability,high rate capability,and long-term durability.Herein,we designed an AB_(4)-type La_(0.6)0Sm_(0.22)Mg_(0.18)Ni_(4.09)Al_(0.09)Mn_(0.10)alloy that manifests superior electrochemical performance.The obtained AB_(4)-type single-phase alloy delivers a high discharge capacity of 375.2 mAh·g^(-1)and features outstanding discharge ability at high rates,maintaining 121 mAh·g^(-1)even at a discharge rate of 6C.The excellent high-rate discharge performance can be attributed to its fast charge transfer and hydrogen diffusion kinetics.Moreover,the AB_(4)-type alloy maintains a capacity retention of 84.5%after 200 cycles and retains 55.7%of its capacity retention even after 500 cycles.This work provides a good alternative to hydrogen storage alloy with high power and long cycling durability performance for nickel metal hydride batteries.
基金financial support from the Natural Science Foundation of China(No.11904089,12174092,11674087)the Overseas Expertise Introduction Center for Discipline Innovation(D18025)+1 种基金the Program for Key Research and Development of Science and Technology in Hubei Province(grant No.2023BEB002)supported by the Young Science Foundation of Hubei University(Grant No.430/184303000047).
文摘Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.
基金the financial support provided by the Longzihu New Energy Laboratory Joint Fund of Henan Province(2023008)the Energy Storage Mater.and Processes Key Laboratory of Henan Province Open Fund(2021003)+1 种基金the Collaborative Innovation Team Project Fund of Industry-University-Research(32214085)the financial support received from Zhejiang Vast Na Technology Co.,Ltd.(24110380)。
文摘To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃reheating strategy.This method improves the surface properties of NFM without the need for additional coating layers,making it more efficient and suitable for large-scale applications.Pristine NFM(NFM-P)was first synthesized through a high-temperature solid-state method and then modified using this reheating approach(NFM-HT).This strategy significantly enhances air stability and electrochemical performance,yielding an initial discharge specific capacity of 151.46 mAh/g at 0.1C,with a remarkable capacity retention of 95.04%after 100 cycles at 0.5C.Additionally,a 1.7 Ah NFM‖HC(hard carbon)pouch cell demonstrates excellent long-term cycling stability(94.64%retention after 500 cycles at 1C),superior rate capability(86.48%retention at 9C),and strong low-temperature performance(77%retention at-25℃,continuing power supply at-40℃).Notably,even when overcharged to 8.29 V,the pouch cell remained safe without combustion or explosion.This reheating strategy,which eliminates the need for a coating layer,offers a simpler,more scalable solution for industrial production while maintaining outstanding electrochemical performance.These results pave the way for broader commercial adoption of NFM materials.
基金supported by the National Natural Science Foundation of China (22169002)the Chongzuo Key Research and Development Program of China (20220603)the Counterpart Aid Project for Discipline Construction from Guangxi University(2023M02)
文摘P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.
基金financially supported by the Australian Research Council(ARC) through the Future Fellowship(FT180100705)the financial support from China Scholarship Council+3 种基金the support from UTS-HUST Key Technology Partner Seed Fundthe support from Open Project of State Key Laboratory of Advanced Special Steel,the Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2021-04)the Science and Technology Commission of Shanghai Municipality(22010500400)“Joint International Laboratory on Environmental and Energy Frontier Materials”and“Innovation Research Team of High–Level Local Universities in Shanghai”in Shanghai University。
文摘The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.
基金supported by the Science and Technology Program of Suzhou(ST202304)the National Natural Science Foundation of China(12275189)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 project。
文摘O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.52372188,51902090)Henan Key Research Project Plan for Higher Education Institutions(No.23A150038)+6 种基金2023 Introduction of Studying Abroad Talent Program“111”Project(No.D17007)Henan Provincial Key Scientific Research Project of Colleges and Universities(No23A150038)Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National Students’Platform for Innovation and Entrepreneurship Training Program(No.201910476010)the China Postdoctoral Science Foundation(No.2019 M652546)the Henan Province Postdoctoral StartUp Foundation(No.1901017)。
文摘Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.
基金This work was supported financially by the National Natural Science Foundation of China(Nos.52304397 and U19A2085)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022B1515120082 and 2019B030302010)+1 种基金the Guangdong Science and Technology Innovation Project(No.2021TX06C111)the Optical Valley Science Research Project,WEHDZ(No.2019001).
文摘Additive manufacturing ofβ-type titanium alloy is expected to replace Ti-6Al-4V alloy in the field of orthopedic implantation because of their low elastic modulus,excellent corrosion resistance,and biocompatibility.After briefly introducing the laser powder bed fusion(LPBF)process and physical phenomena,this paper reviews the recent progresses in LPBF-edβ-type Ti alloys.The strategies to strengthening and tougheningβ-type Ti alloys are critically reviewed.This is followed by the processing routes employed to achieve to low modulus for orthopedic applications,especially a new methodology for tailoring crystallographic orientation called multi-track coupled directional solidification.The effect of processing and compositions on performance metrics ofβ-type Ti alloys included corrosion behavior,and biocompatibility is reviewed.In the end,challenges in additive manufacturing ofβ-type Ti alloys in future are highlighted,with the aim to ensue clinical application of LPBF-edβ-type Ti alloys.
基金funded by the National Natural Science Foundation of China(Grant Nos.22279092 and 5202780089).
文摘Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.However,continuous voltage decay during cycling remains the primary obstacle for practical applications,which has yet to be fundamentally addressed.It is widely acknowledged that voltage decay originates from the irreversible migration of transition metal ions,which usually further exacerbates structural evolution and aggravates the irreversible oxygen redox reactions.Recently,constructing O2-type structure has been considered one of the most promising approaches for inhibiting voltage decay.In this review,the relationship between voltage decay and structural evolution is systematically elucidated.Strategies to suppress voltage decay are systematically summarized.Additionally,the design of O2-type structure and the corresponding mechanism of suppressing voltage decay are comprehensively discussed.Unfortunately,the reported O2-type LRLO cathodes still exhibit partially disordered structure with extended cycles.Herein,the factors that may cause the irreversible transition metal migrations in O2-type LRLO materials are also explored,while the perspectives and challenges for designing high-performance O2-type LRLO cathodes without voltage decay are proposed.
基金Project supported by the National Key R&D Program of China(2022YFB3807000)Innovation Funds of CRIMAT Engineering Institute Co.,Ltd.Campus France under Cai Yuanpei project(44027 WH)。
文摘AB_(2)-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering their application is hydrogen induced amorphization(HIA),which leads to the irreversible hydrogen sorption process.The stability of the AB_2 Laves phase compounds,the structural properties,the hydrogenation properties and the controlling factors of HIA are discussed in this review.Comparing with other factors,the atomic radii ratio r_A/r_B is the most important one influencing the HIA.Multi-element substitution is an efficient way to suppress or limit HIA and may enable AB_2 compounds to be suitable for hydrogen storage.
基金supported by the National Natural Science Foundation of China(Nos.22179077,51774251,21908142)Shanghai Science and Technology Commission’s“2020 Science and Technology In-novation Action Plan”(No.20511104003)Natural Science Foundation in Shanghai(No.21ZR1424200)。
文摘The Na-deficient P3-type layered oxide cathode material usually experience complex in-plane Na^(+)/vacancy ordering rearrangement and undesirable P3-O3 phase transitions in the high-voltage region,leading to inferior cycling performance.Additionally,they exhibit unsatisfactory stability when exposed to water for extended periods.To address these challenges,we propose a Cu/Ti co-doped P3-type cathode material(Na_(0.67)Ni_(0.3)Cu_(0.03)Mn_(0.6)Ti_(0.07)O_(2)),which effectively mitigates Na^(+)/vacancy ordering and suppresses P3-O3 phase transitions at high voltages.As a result,the as-prepared sample exhibited outstanding cyclic performance,with 81.9%retention after 500 cycles within 2.5–4.15 V,and 75.7%retention after300 cycles within 2.5–4.25 V.Meanwhile,it demonstrates enhanced Na^(+)transport kinetics during desodiation/sodiation and reduced growth of charge transfer impedance(R_(ct))after various cycles.Furthermore,the sample showed superb stability against water,exhibiting no discernible degradation in structure,morphology,or electrochemical performance.This co-doping strategy provides new insights for innovative and prospective cathode materials.
基金Project supported by the National Natural Science Foundation of China(52271214,51831009)。
文摘Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage,as well as successful application as nickel-metal hydride batteries anodes.In this work,Y substitution was carried out to adjust the gaseous hydrogen storage properties of A_(2)B_(7)-type La_(0.7)Mg_(0.3)Ni_(3.5)alloys.The results indicate a multiphase structure in the alloys comprised of the main rhombohedral Gd_(2)Co_(7)and PuNi_(3)phases,with a small amount of CaCu_(5)phase.Moreover,the Y substitution results in higher abundance of the Gd_(2)Co_(7)phase.The alloy La_(0.42)Y_(0.28)Mg_(0.3)Ni_(3.5)exhibits a hydrogen storage cap acity of 1.55 wt%at 298 K and a desorption plateau pressure of 0.244 MPa.In addition,this alloy demonstrates a stable cycle life by a capacity retention of 94.2%after 50 cycles,with the main capacity degradation occurring during the initial 20 cycles.This work accentuates the potential of the La-Y-Mg-Ni-based superlattice alloys for applications in solid-state hydrogen storage.
基金financially supported by the National Key Research and Development Program of China(2022YFB3803804)the National Natural Science Foundation of China(Nos.51971197,52071281 and 52201282)+3 种基金Basic Innovation Research Project in Yanshan University(No.2022LGZD004)China Postdoctoral Science Foundation(2023M742945)Postdoctoral research project of Hebei Province(B2023003023)Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(No.22567616H)。
文摘A novel approach based on thermal diffusion was used to achieve controllable Mg content in A_(2)B_(7)-type La-Mg-Ni-based alloys.The formation mechanism of the A_(2)B_(7)-type phase as a result of the thermal diffusion process and the effect of Mg content on hydrogen storage performance were investigated.X-ray diffraction(XRD)patterns and Rietveld refinement results showed that increased Mg transformed the LaNi_(5)phase in the La_(0.74)Sm_(0.03)Y_(0.23)Ni_(4.32)Al_(0.04)precursor alloy into a superlattice structure.Scanning electron microscopy(SEM)images showed that Mg was evenly distributed in the alloy bulk.Mg in the superlattice significantly inhibited the phase decomposition of the superlattice structure during the hydrogen absorption/desorption cycles.An A_(2)B_(7)-type La_(0.57)Sm_(0.02)Y_(0.18)Mg_(0.23)Ni_(3.38)Al_(0.03)alloy composed of Gd_(2)Co_(7)and Ce_(2)Ni_(7)phases was successfully synthesized.The pressure-composition isotherm profiles showed that the alloy had a hydrogen storage capacity as high as 1.73 wt%,with good cycling stability.After 50 cycles of hydrogen absorption/desorption,the alloy retained a hydrogen storage capacity of 1.45 wt%,with a capacity retention rate of up to 84.28%.The Mg thermal diffusion process thus provides a new approach for the controlled preparation of La-Mg-Ni-based alloys.
