Electrocatalysts are an effective strategy to mitigate the shuttling effect of lithium polysulfides(LiPSs)and accelerate the redox kinetics of LiPSs in lithium-sulfur(Li-S)batteries.However,traditional electrocatalyst...Electrocatalysts are an effective strategy to mitigate the shuttling effect of lithium polysulfides(LiPSs)and accelerate the redox kinetics of LiPSs in lithium-sulfur(Li-S)batteries.However,traditional electrocatalysts only have a single active site and often undergo structural collapse and aggregation during charging and discharging,resulting in reduced catalytic performance.Herein,the two-dimensional(2D)polar high-entropy La_(0.71)Sr_(0.29)Co_(0.21)Ni_(0.20)Fe_(0.19)Cr_(0.20)Cu_(0.20)O_(3)(LCO-HEO)nanosheets were rationally designed and successfully synthesized to address this issue.The distinct functional polar sites in LCOHEOs were formed by the d-d orbital hybridization between spatially coupling adjacent transition metals,which can strengthen the dipole-dipole interaction between polar LCO-HEOs and polar LiPSs.2D polar LCO-HEO nanosheets can efficiently capture and trigger the tandem catalysis of polar LiPSs during their sequential conversion.The S/LCO-HEO composite cathode exhibits a high specific capacity of 1161.1 mA h g^(-1)at 1.0 C,with an ultralow capacity attenuation rate of 0.036%per cycle over 1200 cycles,and achieves stable cycling for 1500 cycles even at 8.0 C.Furthermore,even with a high sulfur loading(5.5 mg cm^(-2))and a low electrolyte/sulfur(E/S)ratio(4.0μL mg^(-1)),the S/LCO-HEO composite cathode shows desirable sulfur utilization and good cycle stability.This work demonstrates the feasibility of high entropy-driven multiple distinct functional polar sites for high-rate and long-cycle Li-S batteries.展开更多
High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifi...High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifically (PtFeCoNiCu)O/C,using a carbothermal shock (CTS) method for application as a cathode catalyst in direct borohydride fuel cells (DBFCs).The microstructure of the prepared catalysts was characterized by X-ray photoelectron spectroscopy,X-ray absorption fine structure,and transmission electron microscopy.The prepared (PtFeCoNiCu)O/C,with particle sizes ranging from 2 to 4 nm,demonstrates 3.94 transferred electrons towards the oxygen reduction reaction in an alkaline environment,resulting in a minimal H_(2)O_(2)yield of 2.6%.Additionally,it exhibits a Tafel slope of 61 mV dec-1,surpassing that of commercial Pt/C (82 mV dec-1).Furthermore,after 40,000 cycles of cyclic voltammetry(CV) testing,the half-wave potential of (PtFeCoNiCu)O/C shows a positive shift of 3 mV,with no notable decline in the limiting current density.When (PtFeCoNiCu)O/C is used as a cathode catalyst in DBFCs,the DBFC achieves a maximum power density of 441 mW cm^(-2)at 60°C and sustains a cell voltage of approximately 0.73 V after 52 h at 30°C.These findings confirm that HEO/C is a promising cathode catalyst for DBFCs.展开更多
High-entropy oxides(HEOs),offering reversible lithium storage and moderate operating potential,are considered promising negative electrodes.However,the intricate lithium storage mechanism within HE polycationic system...High-entropy oxides(HEOs),offering reversible lithium storage and moderate operating potential,are considered promising negative electrodes.However,the intricate lithium storage mechanism within HE polycationic systems remains challenging.Here,we conduct comprehensive investigations into the electrochemical properties and structu ral evolution of(CrMnCoNiZn)_(3)O_(4)(HESO)to clarify lithium storage mechanisms.Density functional theory(DFT)calculations reveal that polycationic synergy modulates the electronic structure and d-band centers of HESO,delivering fast electrode kinetics.Exhaustive in-and exsitu analyses demonstrate that the residual crystalline phases acting as seed crystals maintain the spinel/rock-salt lattice persistence under the entropy stabilization effect,lattice distortion effect,and cation synergy,which guide cation crystallization upon the electric field to drive reversible lithium storage.Such properties underlie the HESO electrode with an exceptional rate and long-term capability.This work clarifies the roles of cationic synergy and seed-crystal-driven structural reversibility,providing a blueprint for designing high-performance HEO negative electrodes for next-generation lithium-ion batteries(LIBs).展开更多
Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition ...Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition and electronic structure.Theoretically,the rapid ion transport and the abundance of surface defects in high-entropy materials suggest a potential for enhancing the performance of composite solid-state electrolytes(CPEs).Herein,using a high-entropy oxide(HEO)filler to assess its potential contributions to CPEs is proposed.The distinctive structural distortions in HEO significantly improve the ionic conductivity(5×10^(−4) S·cm^(−1) at 60℃)and Li-ion transference number(0.57)of CPEs.Furthermore,the enhanced Li-ion transport capability extends the critical current density from 0.6 to 1.5 mA·cm^(−2) in Li/Li symmetric cells.In addition,all-solid-state batteries incorporating the HEO-modified CPEs exhibit superior rate performance and cycling stability.The work will enrich the application of HEOs in CPEs and provide fundamental understanding.展开更多
Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor...Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice distortion.Here,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced HEOs.Among the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic interactions.Particularly,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 K.Moreover,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκefficiently.This work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.展开更多
High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in electrocatalysis.In this study,a Pt/(FeCo...High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in electrocatalysis.In this study,a Pt/(FeCoNiCrAl)_(3)O_(4)nanohybrid using HEO as a support was developed as an efficient catalyst for the hydrogen evolution reaction(HER).Pt/(FeCoNiCrAl)_(3)O_(4)exhibited high HER activity with a low overpotential of 22 mV at10 mA·cm^(-2),outperforming other binary,ternary,and quaternary supports.The HER activity of Pt/(FeCoNiCrAl)_(3)O_(4)was higher than that of a commercial Pt/C with a significantly lower Pt loading.The catalyst exhibited good activity and long-term stability(60 h)in an electrolytic water-splitting device.This good activity can be attributed to the fact that the introduction of Pt effectively facilitates electronic interactions between Pt and the HEO.In addition,the HEO substrate was more favorable for dispersing Pt particles,optimizing the electrochemical specific surface area,and significantly reducing the charge resistance of the HER.This study extends the application of HEOs in electrocatalysis and demonstrates the promising prospects of HEOs as supports for electrocatalysts.展开更多
03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na^(+)diffusion kinetics pose sig...03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na^(+)diffusion kinetics pose significant challenges to achieve high-performance layered cathodes.Herein,a boron-doped03-type high entropy oxide Na(Fe_(0.2)Co_(0.15)Cu_(0.05)Ni_(0.2)Mn_(0.2)Ti_(0.2))B_(0.02)O_(2)(NFCCNMT-B_(0.02))is designed and the covalent B-O bonds with high entropy configuration ensure a robust layered structure.The obtained cathode NFCCNMT-B_(0.02)exhibits impressive cycling performance(capacity retention of 95%and 82%after100 cycles and 300 cycles at 1 and 10 C,respectively)and outstanding rate capability(capacity of 83 mAh g^(-1)at 10 C).Furthermore,the NFCCNMT-B_(0.02)demonstrates a superior wide-temperature performance,maintaining the same capacity level(113,4 mAh g^(-1)@-20℃,121 mAh g^(-1)@25℃,and 119 mAh g^(-1)@60℃)and superior cycle stability(90%capacity retention after 100 cycles at 1 C at-20℃).The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance.The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes(ΔV=0.65 A3).B ions doping expands the Na layer distance and enlarges the P3 phase region,thereby enhancing Na^(+)diffusion kinetics.This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.展开更多
High-entropy oxides(HEOs)are gaining prominence in the field of electrochemistry due to their distinctive structural characteristics,which give rise to their advanced stable and modifiable functional properties.This r...High-entropy oxides(HEOs)are gaining prominence in the field of electrochemistry due to their distinctive structural characteristics,which give rise to their advanced stable and modifiable functional properties.This review presents fundamental preparations,incidental characterizations,and typical structures of HEOs.The prospective applications of HEOs in various electrochemical aspects of electrocatalysis and energy conversion-storage are also summarized,including recent developments and the general trend of HEO structure design in the catalysis containing oxygen evolution reaction(OER)and oxygen reduction reaction(ORR),supercapacitors(SC),lithium-ion batteries(LIBs),solid oxide fuel cells(SOFCs),and so forth.Moreover,this review notes some apparent challenges and multiple opportunities for the use of HEOs in the wide field of energy to further guide the development of practical applications.The influence of entropy is significant,and high-entropy oxides are expected to drive the improvement of energy science and technology in the near future.展开更多
A new class of high-entropy oxide glasses 20LaO_(3/2)-20TiO_(2)-20NbO_(5/2)-20WO_(3)-20MO_(3/2)(M=B/Ga/In)were designed and successfully fabricated by aerodynamic containerless processing.The results show that one can...A new class of high-entropy oxide glasses 20LaO_(3/2)-20TiO_(2)-20NbO_(5/2)-20WO_(3)-20MO_(3/2)(M=B/Ga/In)were designed and successfully fabricated by aerodynamic containerless processing.The results show that one can control the properties and increase the functionality of glass by changing the type of M.The Vicker's hardness reaches the highest value of 6.45 GPa for glass M=B.The best thermal stability and the glass forming ability,measured using the glass-transition temperature T_(g) and the temperature gap ΔT respectively,are found in glass M=In,with T_(g)=740℃ and ΔT=72℃.The optical properties show that the as-prepared glasses exhibit good transparency and high refractive index.Especially for glass M=In,its transmittance reaches almost 78% from visible to IR region,and the value is nearly unchanged after electron beam irradiation,indicating good irradiation resistance of this high-entropy oxide glass.Furthermore,the glass M=In has the highest refractive index(n_(d)=2.46) and low wavelength dispersion(v_(d)=45.6).These results demonstrate that the conceptual design of high-entropy materials is adaptable to high performance oxide glasses,which should be promising host materials for optical applications such as smart phones with digital cameras and endoscopes.展开更多
Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs of...Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.展开更多
High-entropy oxides(HEOs)composed of multiple metal elements have garnered significant attention as anode materials for lithium-ion batteries(LIBs),owing to their synergistic effects between constituent metal oxides a...High-entropy oxides(HEOs)composed of multiple metal elements have garnered significant attention as anode materials for lithium-ion batteries(LIBs),owing to their synergistic effects between constituent metal oxides and broad material design flexibility.However,the advancement of HEOs in LIBs has been hindered by time-consuming synthesis methods,complex fabrication procedures,and an insufficient understanding of their lithium storage mechanisms.In this study,a rock-salt structure HEO Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(_(0.2))Zn_(0.2)O was ultrafast synthesized by the Joule heating technique within 3 s and was applied to LIBs for the first time as a conversion-type anode material.The material exhibits not only excellent capacity retention but also remarkable structural reversibility.Specifically,the reversible capacity is determined to be 1310 mAh/g for 200 cycles at 0.1 A/g,and 705 mAh/g for 3000 cycles at 5 A/g.Detailed mechanistic investigations reveal that ZnO serves as an electrochemically inactive structural stabilizer that maintains the rock-salt framework,while Cu^(2+)is difficult to oxidize back to its original state once reduced to Cu^(0).This study provides critical insights into the composition-structure-property relationships of HEOs,offering valuable guidance for designing high-performance LIBs anode materials through entropy engineering.展开更多
Ethyl acetate(EA)is a stable oxygenated volatile organic compound(VOC)that is challenging to fully degrade due to its strong chemical bonds.High-entropy metal oxides(HEOs)with their active lattice oxygens and diverse ...Ethyl acetate(EA)is a stable oxygenated volatile organic compound(VOC)that is challenging to fully degrade due to its strong chemical bonds.High-entropy metal oxides(HEOs)with their active lattice oxygens and diverse metal-oxygen bonds hold great potential for efficient degradation of EA.However,synthesizing HEOs without phase separation remains a significant challenge.In this study,we developed an electrospinning method to synthesize spinel-type high-entropy(CoMnNiFeZn)O_(x) catalysts,achieving 90%EA conversion at 266℃ with a CO_(2) selectivity of 100%.The catalyst demonstrated a high turnover frequency of 101.5±0.8 h^(−1) based on the total metal content.The optimal 1 mmolHEO catalyst demonstrated excellent stability in both fivecycle and thermal stability tests.An ^(18)O isotope-labelled experiment confirmed that the oxidation of EA follows the Marsvan-Krevelen mechanism,with high lattice oxygen mobility significantly enhancing catalytic activity.Furthermore,in situ diffuse reflectance infrared Fourier transform spectroscopy provided insights into the roles of different metal-oxygen bonds in the catalytic mechanism.This work deepens the understanding of metal-oxygen bond interactions in the oxidation of oxygenated VOCs and offers a viable approach for synthesizing HEOs.展开更多
As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise beca...As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise because of their high energy conversion efficiency and wide range of applications.Highentropy materials(HEMs),a novel class of materials comprising several principal elements,have attracted significant interest within the materials science and energy sectors.Their distinctive structural features and adaptable functional properties offer immense potential for innovation across various applications.This review systematically covers the basic concepts,crystal structures,element selection,and major synthesis strategies of HEMs,and explores in detail the specific applications of these materials in SOCs,including its potential as air electrodes,fuel electrodes,electrolytes,and interconnects(including barrier coatings).By analyzing existing studies,this review reveals the significant advantages of HEMs in enhancing the performance,anti-poisoning,and stability of SOCs;highlights the key areas and challenges for future research;and looks into possible future directions.展开更多
High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special clas...High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special class of oxides containing five or more different metal cations.The attractive synergistic effect makes HEOs promising energy storage and conversion material.However,at present,the knowledge of HEOs and their practical applications on electrochemistry is still scattered without comprehensive report.In this review,we highlight the preparation methods,common crystal structures and their applications in the field of electrochemistry,which can be divided into two main categories:(1)electrochemical energy storage devices,including supercapacitors,lithium-ion batteries,sodium-ion batteries,and other batteries;(2)electrocatalysis reaction system,including hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and electrocatalytic CO_(2)reduction reaction(CO_(2)RR).Finally,the remaining challenges and prospects in the future are envisioned in the related field,which will help to unlock the mysteries of HEOs for energy storage and conversion.展开更多
High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that ...High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.展开更多
The insufficient stability and poor surface reaction kinetics(i.e.,oxygen reduction reaction(ORR)and oxygen evolution reaction(OER))of air electrodes are significant factors hindering the development of reversible sol...The insufficient stability and poor surface reaction kinetics(i.e.,oxygen reduction reaction(ORR)and oxygen evolution reaction(OER))of air electrodes are significant factors hindering the development of reversible solid oxide cells(R-SOCs).The high-entropy strategy offers a new direction to optimize air electrodes.We introduce a high-entropy air electrode,(La_(0.12)Pr_(0.12)Nd_(0.12)Sm_(0.12)Gd_(0.12))Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LPNSGSrCF),demonstrating a low polarization resistance(0.15Ωcm^(2))and good durability(1.3×10^(-3)Ωcm^(2)h^(-1)),superior to those of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(0.31Ωcm^(2),2.0×10^(-3)Ωcm^(2)h^(-1))at 650℃.The elevated activity may be a result of the substantial concentration of oxygen vacancies and rapid reaction kinetics,as verified by X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and distribution of relaxation times studies.Specifically,an R-SOC with LPNSGSrCF air electrode achieves a peak power density of 1.05 W cm^(-2)in fuel cell mode and a current density of0.89 A cm^(-2)at 1.3 V in electrolysis cell mode(with 30%H_(2)O)at 700℃.Moreover,the cells with LPNSGSrCF electrode can be stably operated in both modes for over 100 h.展开更多
Rational design of viable routes to obtain efficient and stable oxygen evolution reaction(OER)electrocatalysts remains challenging,especially under industrial conditions.Here,we provide a solvent-steam assisted corros...Rational design of viable routes to obtain efficient and stable oxygen evolution reaction(OER)electrocatalysts remains challenging,especially under industrial conditions.Here,we provide a solvent-steam assisted corrosion engineering strategy to directly fabricate high-entropy NiF e-LDH with spatially resolved structural order.Ammonium fluoride in methanol steam enables the formation of nanosheets while Fe^(3+)effectively enhances their adhesion to the semi-sacrificial nickel-iron foam(NFF),thereby conjuring up a Ni Fe-LDH@NFF catalyst that exhibits remarkable adaptability to robust electrochemical activation yet with excellent stability.Comprehensive measurements reveal the in-situ formation of high-valance metal oxyhydroxide and the enhancement of adsorption-desorption process.Under the industrial condition(6 mol/L KOH,60℃),the Ni Fe-LDH@NFF exhibits excellent activity of 50 mA/cm^(2) at 1.55 V and high durability of over 120 h at 200 mA/cm^(2).We anticipate that the steam assisted strategy could promote the development of efficient non-precious electrocatalysts for hydrogen energy.展开更多
Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchang...Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchange membrane water electrolysis.Here,homogeneous high entropy oxide(HEO)film is in-situ fabricated on nickel foam(NF)substrate via magnetron sputtering technology without annealing process in air,which is composed of many spinel-structured(FeCoNiCrMo)_(3)O_(4) grains with an average particle size of 2.5 nm.The resulting HEO film(abbreviated as(FeCoNiCr-Mo)_(3)O_(4))exhibits a superior OER performance with a low OER overpotential of 216 mV at 10 mA cm^(–2) and steadily operates at 100 mA cm^(–2) for 200 h with a decay of only 272μV h^(–1),which is far better than that of commercial IrO_(2) catalyst(290 mV,1090μV h^(–1)).Tetramethylammonium cation(TMA^(+))probe experiment,activation energy analysis and theoretical calculations unveil that the OER on(FeCoNiCrMo)_(3)O_(4) follows an adsorbate evolution mechanism pathway,where the energy barrier of rate-determining step for OER on(FeCoNiCrMo)_(3)O_(4) is substantially lowered.Also,methanol molecular probe experiment suggests that a weakened ^(*)OH bonding on the(FeCoNiCrMo)_(3)O_(4) surface and a rapid deprotonation of ^(*)OH,further enhancing its OER performance.This work provides a feasible solution for designing efficient high entropy oxides electrocatalysts for OER,accelerating the practical process of water electrolysis for H2 production.展开更多
The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-medi...The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.展开更多
The present work aims to create lattice distortion and optimize the surface oxygen vacancy(OV)concentration in a model spinel(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)high-entropy oxide(HEO)through a heteroat...The present work aims to create lattice distortion and optimize the surface oxygen vacancy(OV)concentration in a model spinel(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)high-entropy oxide(HEO)through a heteroatom La^(3+)doping strategy.As demonstrated,La^(3+)with a large radius can be doped successfully into the spinel lattice of(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4),thereby not only causing lattice distortion to increase oxygen vacancies but also refining crystalline grains and improving the specific area.Compared with the(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)anode,the(La_(0.01)CoCrFeMnNi)_(3/5.01)O_(4) anode with moderate doping exhibits excellent cycling performance(1228 mAh·g^(−1)after 400 cycles at 0.2 A·g^(−1))and yields an increase of 75%rate capability at 3 A·g^(−1)(420 mAh·g^(−1)at 3 A·g^(−1)).The desirable kinetic transport of electrons and diffusion of Li+within the moderately La^(3+)-doped anode and the synergistic interfacial pseudocapacitive behavior satisfy the redox reaction at a high rate,thus increasing rate capability.展开更多
基金supported by grants from the National Natural Science Foundation of China(52072099)Team program of the Natural Science Foundation of Heilongjiang Province,China(No.TD2021E005)Joint Guidance Project of the Natural Science Foundation of Heilongjiang Province,China(No.LH2022E093)。
文摘Electrocatalysts are an effective strategy to mitigate the shuttling effect of lithium polysulfides(LiPSs)and accelerate the redox kinetics of LiPSs in lithium-sulfur(Li-S)batteries.However,traditional electrocatalysts only have a single active site and often undergo structural collapse and aggregation during charging and discharging,resulting in reduced catalytic performance.Herein,the two-dimensional(2D)polar high-entropy La_(0.71)Sr_(0.29)Co_(0.21)Ni_(0.20)Fe_(0.19)Cr_(0.20)Cu_(0.20)O_(3)(LCO-HEO)nanosheets were rationally designed and successfully synthesized to address this issue.The distinct functional polar sites in LCOHEOs were formed by the d-d orbital hybridization between spatially coupling adjacent transition metals,which can strengthen the dipole-dipole interaction between polar LCO-HEOs and polar LiPSs.2D polar LCO-HEO nanosheets can efficiently capture and trigger the tandem catalysis of polar LiPSs during their sequential conversion.The S/LCO-HEO composite cathode exhibits a high specific capacity of 1161.1 mA h g^(-1)at 1.0 C,with an ultralow capacity attenuation rate of 0.036%per cycle over 1200 cycles,and achieves stable cycling for 1500 cycles even at 8.0 C.Furthermore,even with a high sulfur loading(5.5 mg cm^(-2))and a low electrolyte/sulfur(E/S)ratio(4.0μL mg^(-1)),the S/LCO-HEO composite cathode shows desirable sulfur utilization and good cycle stability.This work demonstrates the feasibility of high entropy-driven multiple distinct functional polar sites for high-rate and long-cycle Li-S batteries.
基金Zhejiang Provincial Natural Science Foundation of China (LZ22B060001,LY22E010003)“Pioneer” R&D Program of Zhejiang Province(2023C01080)National Natural Science Foundation of China (52301235)。
文摘High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifically (PtFeCoNiCu)O/C,using a carbothermal shock (CTS) method for application as a cathode catalyst in direct borohydride fuel cells (DBFCs).The microstructure of the prepared catalysts was characterized by X-ray photoelectron spectroscopy,X-ray absorption fine structure,and transmission electron microscopy.The prepared (PtFeCoNiCu)O/C,with particle sizes ranging from 2 to 4 nm,demonstrates 3.94 transferred electrons towards the oxygen reduction reaction in an alkaline environment,resulting in a minimal H_(2)O_(2)yield of 2.6%.Additionally,it exhibits a Tafel slope of 61 mV dec-1,surpassing that of commercial Pt/C (82 mV dec-1).Furthermore,after 40,000 cycles of cyclic voltammetry(CV) testing,the half-wave potential of (PtFeCoNiCu)O/C shows a positive shift of 3 mV,with no notable decline in the limiting current density.When (PtFeCoNiCu)O/C is used as a cathode catalyst in DBFCs,the DBFC achieves a maximum power density of 441 mW cm^(-2)at 60°C and sustains a cell voltage of approximately 0.73 V after 52 h at 30°C.These findings confirm that HEO/C is a promising cathode catalyst for DBFCs.
基金supported by the National Natural Science Foundation of China(No.22271101)the R&D Program of Guangzhou(2024A04J2497)+1 种基金the Key Laboratory of Polymer Chemistry&Physics of Ministry of Educationsupported by the High Performance Computing Platform of SCUT。
文摘High-entropy oxides(HEOs),offering reversible lithium storage and moderate operating potential,are considered promising negative electrodes.However,the intricate lithium storage mechanism within HE polycationic systems remains challenging.Here,we conduct comprehensive investigations into the electrochemical properties and structu ral evolution of(CrMnCoNiZn)_(3)O_(4)(HESO)to clarify lithium storage mechanisms.Density functional theory(DFT)calculations reveal that polycationic synergy modulates the electronic structure and d-band centers of HESO,delivering fast electrode kinetics.Exhaustive in-and exsitu analyses demonstrate that the residual crystalline phases acting as seed crystals maintain the spinel/rock-salt lattice persistence under the entropy stabilization effect,lattice distortion effect,and cation synergy,which guide cation crystallization upon the electric field to drive reversible lithium storage.Such properties underlie the HESO electrode with an exceptional rate and long-term capability.This work clarifies the roles of cationic synergy and seed-crystal-driven structural reversibility,providing a blueprint for designing high-performance HEO negative electrodes for next-generation lithium-ion batteries(LIBs).
基金supported by the National Natural Science Foundation of China(No.52002094)Shenzhen Science and Technology Program(Nos.JCYJ20210324121411031,JSGG202108021253804014 and RCBS20210706092218040)Shenzhen Steady Support Plan(Nos.GXWD20221030205923001 and GXWD20201230155427003-20200824103000001).
文摘Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition and electronic structure.Theoretically,the rapid ion transport and the abundance of surface defects in high-entropy materials suggest a potential for enhancing the performance of composite solid-state electrolytes(CPEs).Herein,using a high-entropy oxide(HEO)filler to assess its potential contributions to CPEs is proposed.The distinctive structural distortions in HEO significantly improve the ionic conductivity(5×10^(−4) S·cm^(−1) at 60℃)and Li-ion transference number(0.57)of CPEs.Furthermore,the enhanced Li-ion transport capability extends the critical current density from 0.6 to 1.5 mA·cm^(−2) in Li/Li symmetric cells.In addition,all-solid-state batteries incorporating the HEO-modified CPEs exhibit superior rate performance and cycling stability.The work will enrich the application of HEOs in CPEs and provide fundamental understanding.
基金supported by National defense ba-sic scientific research(Grant Nos.2022-JCKY-JJ-1086 and 211-CXCY-N103-03-04-00).
文摘Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice distortion.Here,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced HEOs.Among the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic interactions.Particularly,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 K.Moreover,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκefficiently.This work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.
基金financially supported by the National Natural Science Foundation of China(Nos.52122107,51972224 and 52001227)。
文摘High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in electrocatalysis.In this study,a Pt/(FeCoNiCrAl)_(3)O_(4)nanohybrid using HEO as a support was developed as an efficient catalyst for the hydrogen evolution reaction(HER).Pt/(FeCoNiCrAl)_(3)O_(4)exhibited high HER activity with a low overpotential of 22 mV at10 mA·cm^(-2),outperforming other binary,ternary,and quaternary supports.The HER activity of Pt/(FeCoNiCrAl)_(3)O_(4)was higher than that of a commercial Pt/C with a significantly lower Pt loading.The catalyst exhibited good activity and long-term stability(60 h)in an electrolytic water-splitting device.This good activity can be attributed to the fact that the introduction of Pt effectively facilitates electronic interactions between Pt and the HEO.In addition,the HEO substrate was more favorable for dispersing Pt particles,optimizing the electrochemical specific surface area,and significantly reducing the charge resistance of the HER.This study extends the application of HEOs in electrocatalysis and demonstrates the promising prospects of HEOs as supports for electrocatalysts.
基金financially supported by the National Natural Science Foundation of China(No.52071073,52177208,and52171202)Hebei Province“333 talent project”(No.C20221012)+1 种基金the Science and Technology Project of Hebei Education Department(BJK2023005)Hebei Province Graduate Innovation Funding Program CXZZBS2024177。
文摘03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na^(+)diffusion kinetics pose significant challenges to achieve high-performance layered cathodes.Herein,a boron-doped03-type high entropy oxide Na(Fe_(0.2)Co_(0.15)Cu_(0.05)Ni_(0.2)Mn_(0.2)Ti_(0.2))B_(0.02)O_(2)(NFCCNMT-B_(0.02))is designed and the covalent B-O bonds with high entropy configuration ensure a robust layered structure.The obtained cathode NFCCNMT-B_(0.02)exhibits impressive cycling performance(capacity retention of 95%and 82%after100 cycles and 300 cycles at 1 and 10 C,respectively)and outstanding rate capability(capacity of 83 mAh g^(-1)at 10 C).Furthermore,the NFCCNMT-B_(0.02)demonstrates a superior wide-temperature performance,maintaining the same capacity level(113,4 mAh g^(-1)@-20℃,121 mAh g^(-1)@25℃,and 119 mAh g^(-1)@60℃)and superior cycle stability(90%capacity retention after 100 cycles at 1 C at-20℃).The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance.The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes(ΔV=0.65 A3).B ions doping expands the Na layer distance and enlarges the P3 phase region,thereby enhancing Na^(+)diffusion kinetics.This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.
基金The authors are thankful for the financial support from the Beijing Natural Science Foundation(No.3222050)the National Natural Science Foundation of China(Nos.22075304 and 52202324).
文摘High-entropy oxides(HEOs)are gaining prominence in the field of electrochemistry due to their distinctive structural characteristics,which give rise to their advanced stable and modifiable functional properties.This review presents fundamental preparations,incidental characterizations,and typical structures of HEOs.The prospective applications of HEOs in various electrochemical aspects of electrocatalysis and energy conversion-storage are also summarized,including recent developments and the general trend of HEO structure design in the catalysis containing oxygen evolution reaction(OER)and oxygen reduction reaction(ORR),supercapacitors(SC),lithium-ion batteries(LIBs),solid oxide fuel cells(SOFCs),and so forth.Moreover,this review notes some apparent challenges and multiple opportunities for the use of HEOs in the wide field of energy to further guide the development of practical applications.The influence of entropy is significant,and high-entropy oxides are expected to drive the improvement of energy science and technology in the near future.
基金Project supported by the National Natural Science Foundation of China (51972048)the Fundamental Research Funds for the Central Universities (N2123003)。
文摘A new class of high-entropy oxide glasses 20LaO_(3/2)-20TiO_(2)-20NbO_(5/2)-20WO_(3)-20MO_(3/2)(M=B/Ga/In)were designed and successfully fabricated by aerodynamic containerless processing.The results show that one can control the properties and increase the functionality of glass by changing the type of M.The Vicker's hardness reaches the highest value of 6.45 GPa for glass M=B.The best thermal stability and the glass forming ability,measured using the glass-transition temperature T_(g) and the temperature gap ΔT respectively,are found in glass M=In,with T_(g)=740℃ and ΔT=72℃.The optical properties show that the as-prepared glasses exhibit good transparency and high refractive index.Especially for glass M=In,its transmittance reaches almost 78% from visible to IR region,and the value is nearly unchanged after electron beam irradiation,indicating good irradiation resistance of this high-entropy oxide glass.Furthermore,the glass M=In has the highest refractive index(n_(d)=2.46) and low wavelength dispersion(v_(d)=45.6).These results demonstrate that the conceptual design of high-entropy materials is adaptable to high performance oxide glasses,which should be promising host materials for optical applications such as smart phones with digital cameras and endoscopes.
文摘Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.
基金supported by the National Key R&D Program of China(No.2021YFA1202300)This work was also supported by the National Natural Science Foundation of China(No.52372221)+1 种基金WenZhou-2024R3001GuangDong Basic and Applied Basic Research Foundation(No.2023B1515120095).
文摘High-entropy oxides(HEOs)composed of multiple metal elements have garnered significant attention as anode materials for lithium-ion batteries(LIBs),owing to their synergistic effects between constituent metal oxides and broad material design flexibility.However,the advancement of HEOs in LIBs has been hindered by time-consuming synthesis methods,complex fabrication procedures,and an insufficient understanding of their lithium storage mechanisms.In this study,a rock-salt structure HEO Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(_(0.2))Zn_(0.2)O was ultrafast synthesized by the Joule heating technique within 3 s and was applied to LIBs for the first time as a conversion-type anode material.The material exhibits not only excellent capacity retention but also remarkable structural reversibility.Specifically,the reversible capacity is determined to be 1310 mAh/g for 200 cycles at 0.1 A/g,and 705 mAh/g for 3000 cycles at 5 A/g.Detailed mechanistic investigations reveal that ZnO serves as an electrochemically inactive structural stabilizer that maintains the rock-salt framework,while Cu^(2+)is difficult to oxidize back to its original state once reduced to Cu^(0).This study provides critical insights into the composition-structure-property relationships of HEOs,offering valuable guidance for designing high-performance LIBs anode materials through entropy engineering.
基金financially supported by the National Key Research and Development Program of China(2023YFC3906300)the National Natural Science Foundation of China(22478072)the Young Top Talents of Fujian Young Eagle Program。
文摘Ethyl acetate(EA)is a stable oxygenated volatile organic compound(VOC)that is challenging to fully degrade due to its strong chemical bonds.High-entropy metal oxides(HEOs)with their active lattice oxygens and diverse metal-oxygen bonds hold great potential for efficient degradation of EA.However,synthesizing HEOs without phase separation remains a significant challenge.In this study,we developed an electrospinning method to synthesize spinel-type high-entropy(CoMnNiFeZn)O_(x) catalysts,achieving 90%EA conversion at 266℃ with a CO_(2) selectivity of 100%.The catalyst demonstrated a high turnover frequency of 101.5±0.8 h^(−1) based on the total metal content.The optimal 1 mmolHEO catalyst demonstrated excellent stability in both fivecycle and thermal stability tests.An ^(18)O isotope-labelled experiment confirmed that the oxidation of EA follows the Marsvan-Krevelen mechanism,with high lattice oxygen mobility significantly enhancing catalytic activity.Furthermore,in situ diffuse reflectance infrared Fourier transform spectroscopy provided insights into the roles of different metal-oxygen bonds in the catalytic mechanism.This work deepens the understanding of metal-oxygen bond interactions in the oxidation of oxygenated VOCs and offers a viable approach for synthesizing HEOs.
基金supported by the National Key R&D Program of China(2022YFB4004000)National Natural Science Foundation of China(U24A20542,52472210,22279057)+3 种基金Natural Science Foundation of Jiangsu Province(BK20221312)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_1465)Cultivation Program for the Excellent Doctoral Dissertation of Nanjing Tech University(2023-09)the grant of Hydrogen Energy Laboratory(No.FEUZ-2024-0009)。
文摘As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise because of their high energy conversion efficiency and wide range of applications.Highentropy materials(HEMs),a novel class of materials comprising several principal elements,have attracted significant interest within the materials science and energy sectors.Their distinctive structural features and adaptable functional properties offer immense potential for innovation across various applications.This review systematically covers the basic concepts,crystal structures,element selection,and major synthesis strategies of HEMs,and explores in detail the specific applications of these materials in SOCs,including its potential as air electrodes,fuel electrodes,electrolytes,and interconnects(including barrier coatings).By analyzing existing studies,this review reveals the significant advantages of HEMs in enhancing the performance,anti-poisoning,and stability of SOCs;highlights the key areas and challenges for future research;and looks into possible future directions.
基金the Macao Science and Technology Development Fund(FDCT)for funding(FDCT-MOST joint project nos.0026/2022/AMJ,0098/2020/A2,and 006/2022/ALC of the Macao Centre for Research and Development in Advanced Materials(2022-2024))the Natural Science Foundation of Guangdong Province(No.2023A1515010765)+4 种基金the Shenzhen-Hong Kong-Macao Science and Technology Plan Project(Category C)(No.SGDX20220530111004028)the Science and Technology Program of Guangdong Province of China(No.2023A0505030001)the National Natural Science Foundation of China(No.52102264)the Leading Edge Technology of Jiangsu Province(No.BK20220009)the Macao Young Scholars Program(No.AM2022009).
文摘High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special class of oxides containing five or more different metal cations.The attractive synergistic effect makes HEOs promising energy storage and conversion material.However,at present,the knowledge of HEOs and their practical applications on electrochemistry is still scattered without comprehensive report.In this review,we highlight the preparation methods,common crystal structures and their applications in the field of electrochemistry,which can be divided into two main categories:(1)electrochemical energy storage devices,including supercapacitors,lithium-ion batteries,sodium-ion batteries,and other batteries;(2)electrocatalysis reaction system,including hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and electrocatalytic CO_(2)reduction reaction(CO_(2)RR).Finally,the remaining challenges and prospects in the future are envisioned in the related field,which will help to unlock the mysteries of HEOs for energy storage and conversion.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(No.52021004)the Funds for Chongqing Talents Plan(No.CQYC2021059563)+1 种基金the Fundamental Research Funds for the Central Universities(No.2021CDJQY-027)the National Natural Science Foundation of China(No.52206089).
文摘High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.
基金supported by the National Key R&D Program of China(2022YFB4003601)the National Natural Science Foundation of China(22179039)+4 种基金the Introduced Innovative R&D Team of Guangdong(2021ZT09L392)the Guangzhou Science and Technology Project(2024A04J3079)the Guangdong Basic and Applied Basic Research Foundation(2024A1515010448)the Pearl River Talent Recruitment Program(2019QN01C693)Zijin Mining Group Co.,Ltd(5405-ZC-2023-00008).
文摘The insufficient stability and poor surface reaction kinetics(i.e.,oxygen reduction reaction(ORR)and oxygen evolution reaction(OER))of air electrodes are significant factors hindering the development of reversible solid oxide cells(R-SOCs).The high-entropy strategy offers a new direction to optimize air electrodes.We introduce a high-entropy air electrode,(La_(0.12)Pr_(0.12)Nd_(0.12)Sm_(0.12)Gd_(0.12))Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LPNSGSrCF),demonstrating a low polarization resistance(0.15Ωcm^(2))and good durability(1.3×10^(-3)Ωcm^(2)h^(-1)),superior to those of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(0.31Ωcm^(2),2.0×10^(-3)Ωcm^(2)h^(-1))at 650℃.The elevated activity may be a result of the substantial concentration of oxygen vacancies and rapid reaction kinetics,as verified by X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and distribution of relaxation times studies.Specifically,an R-SOC with LPNSGSrCF air electrode achieves a peak power density of 1.05 W cm^(-2)in fuel cell mode and a current density of0.89 A cm^(-2)at 1.3 V in electrolysis cell mode(with 30%H_(2)O)at 700℃.Moreover,the cells with LPNSGSrCF electrode can be stably operated in both modes for over 100 h.
基金supported by the Guangdong Science and Technology Program(No.2023A0505010018)the National Natural Science Foundation of China(No.22309155)the Shenzhen Science and Technology Program(No.JCYJ20200109140421071)。
文摘Rational design of viable routes to obtain efficient and stable oxygen evolution reaction(OER)electrocatalysts remains challenging,especially under industrial conditions.Here,we provide a solvent-steam assisted corrosion engineering strategy to directly fabricate high-entropy NiF e-LDH with spatially resolved structural order.Ammonium fluoride in methanol steam enables the formation of nanosheets while Fe^(3+)effectively enhances their adhesion to the semi-sacrificial nickel-iron foam(NFF),thereby conjuring up a Ni Fe-LDH@NFF catalyst that exhibits remarkable adaptability to robust electrochemical activation yet with excellent stability.Comprehensive measurements reveal the in-situ formation of high-valance metal oxyhydroxide and the enhancement of adsorption-desorption process.Under the industrial condition(6 mol/L KOH,60℃),the Ni Fe-LDH@NFF exhibits excellent activity of 50 mA/cm^(2) at 1.55 V and high durability of over 120 h at 200 mA/cm^(2).We anticipate that the steam assisted strategy could promote the development of efficient non-precious electrocatalysts for hydrogen energy.
文摘Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchange membrane water electrolysis.Here,homogeneous high entropy oxide(HEO)film is in-situ fabricated on nickel foam(NF)substrate via magnetron sputtering technology without annealing process in air,which is composed of many spinel-structured(FeCoNiCrMo)_(3)O_(4) grains with an average particle size of 2.5 nm.The resulting HEO film(abbreviated as(FeCoNiCr-Mo)_(3)O_(4))exhibits a superior OER performance with a low OER overpotential of 216 mV at 10 mA cm^(–2) and steadily operates at 100 mA cm^(–2) for 200 h with a decay of only 272μV h^(–1),which is far better than that of commercial IrO_(2) catalyst(290 mV,1090μV h^(–1)).Tetramethylammonium cation(TMA^(+))probe experiment,activation energy analysis and theoretical calculations unveil that the OER on(FeCoNiCrMo)_(3)O_(4) follows an adsorbate evolution mechanism pathway,where the energy barrier of rate-determining step for OER on(FeCoNiCrMo)_(3)O_(4) is substantially lowered.Also,methanol molecular probe experiment suggests that a weakened ^(*)OH bonding on the(FeCoNiCrMo)_(3)O_(4) surface and a rapid deprotonation of ^(*)OH,further enhancing its OER performance.This work provides a feasible solution for designing efficient high entropy oxides electrocatalysts for OER,accelerating the practical process of water electrolysis for H2 production.
基金The authors thank the National Key R&D Program of China(No.2021YFB4000200)the National Natural Science Foundation of China(No.22232004)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21090400)the Jilin Province Science and Technology Development Program(Nos.20210301008GX,YDZJ202202CXJD011,and 20210502002ZP)for financial support.
文摘The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.
基金supported by the University Natural Science Research Project of Anhui Province in China(No.2023AH051104)the Director’s Fund of Key Laboratory of Green Fabrication and Surface Technology of Advance Metal Materials,Ministry of Education(No.GFST2022ZR08).
文摘The present work aims to create lattice distortion and optimize the surface oxygen vacancy(OV)concentration in a model spinel(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)high-entropy oxide(HEO)through a heteroatom La^(3+)doping strategy.As demonstrated,La^(3+)with a large radius can be doped successfully into the spinel lattice of(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4),thereby not only causing lattice distortion to increase oxygen vacancies but also refining crystalline grains and improving the specific area.Compared with the(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)anode,the(La_(0.01)CoCrFeMnNi)_(3/5.01)O_(4) anode with moderate doping exhibits excellent cycling performance(1228 mAh·g^(−1)after 400 cycles at 0.2 A·g^(−1))and yields an increase of 75%rate capability at 3 A·g^(−1)(420 mAh·g^(−1)at 3 A·g^(−1)).The desirable kinetic transport of electrons and diffusion of Li+within the moderately La^(3+)-doped anode and the synergistic interfacial pseudocapacitive behavior satisfy the redox reaction at a high rate,thus increasing rate capability.
