High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic f...High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic features enable forming-free resistive switching,multilevel conductance modulation,and synaptic plasticity,making HEOs attractive for neuromorphic computing.This review outlines recent progress in HEO-based memristors across materials engineering,switching mechanisms,and synaptic emulation.Particular attention is given to vacancy migration,phase transitions,and valence-state dynamics—mechanisms that underlie the switching behaviors observed in both amorphous and crystalline systems.Their relevance to neuromorphic functions such as short-term plasticity and spike-timing-dependent learning is also examined.While encouraging results have been achieved at the device level,challenges remain in conductance precision,variability control,and scalable integration.Addressing these demands a concerted effort across materials design,interface optimization,and task-aware modeling.With such integration,HEO memristors offer a compelling pathway toward energy-efficient and adaptable brain-inspired electronics.展开更多
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
Recently,the strategy of tuning the dielectric parameters of absorbers for their excellent electromag-netic wave absorption(EMA)performance has attracted much attention.Among those candidates used for EMA application,...Recently,the strategy of tuning the dielectric parameters of absorbers for their excellent electromag-netic wave absorption(EMA)performance has attracted much attention.Among those candidates used for EMA application,high-entropy oxides(HEOs)can be implemented with this strategy due to their rich composition modulability.In this work,a series of implementation approaches varying from elemental design to structural modulation are employed to modulate the dielectric parameters of HEOs,resulting in their excellent EMA performance.The addition of Ti element optimizes the dipole distribution at the microscopic scales,improving the dielectric polarization of the materials.Moreover,a composite mate-rial is constructed by physically blending HEO with acetylene black(ACET),which significantly improves the macroscopic conduction loss of the material.The optimization of the dielectric genes of HEO/ACET is achieved with the blending effect and excellent EMA performance could be obtained.Among them,HEO with 17.5%ACET addition exhibits dual-band absorption,while Ti-HEO containing Ti element exhibits not only low-frequency absorption with reflection loss(RL)up to-29.81 dB at C-band but broadband absorption over 6 GHz as well as an optimal RL value up to-52.31 dB.In addition to the development of innovative EMA materials,this study offers a new perspective on how the EMA characteristics can be effectively regulated.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)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
Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient cata...Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient catalysts due to their complementary elemental and structural properties.We developed a deposition in-situ reduction(D-ISR)approach for the rapid synthesis of single-phase medium/high-entropy oxides(M/HEOs)at room temperature,along with establishing general criteria for M/HEOs synthesis based on component properties.Deposition facilitates the incorporation of active elements(Ti/Zr/V/Cr/Nb),which significantly enhance the enthalpy-driven force of the dynamic oxidation(DO)process via an“active element coordination”strategy,thereby overcoming low-temperature solid solubility limitations.Nine-component HEOs and large-scale experiments confirm the universality and mass-production potential of the D-ISR approach.CoCuNiTi-O/AC synthesized via this strategy exhibits pronounced crystal distortion and disorder(Co–O coordination number=10.2),enhancing the Co–O coordination environment and mitigating Ostwald ripening.This leads to high activity and significantly enhanced structural stability,achieving a turnover frequency of 236.6 min^(-1)for ammonia borane hydrolysis,15 times higher than Co-O/AC and surpassing the most non-noble catalysts.These observations highlight an efficient M/HEOs synthesis methodology that advances M/HEMs applications in nanoenergy.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
As a novel material,high-entropy compounds have attracted extensive attention in the field of lithium–sulfur battery host materials due to their diverse elemental composition with a wide range of properties.The abili...As a novel material,high-entropy compounds have attracted extensive attention in the field of lithium–sulfur battery host materials due to their diverse elemental composition with a wide range of properties.The ability to effectively mitigate the shuttle effect of lithium polysulfides and catalyze the bidirectional conversion of Li_(2)S_(2)/Li_(2)S is crucial to enhance the overall performance of the battery.In this study,a unique sulfur host nanosized highentropy material comprising selenium-doped HEO(AlCrFeCoNi)_(3)O_(4-x)-Se_(x)is fabricated using an in situ thermal reduction and selenylation method.In the high-entropy compounds,the introduction of Se causes that the generation of oxygen vacancies during the lattice distortion serves as ion transfer pathway and the formation of M-Se bonds provides a high adsorption capability for LiPSs.Moreover,the polymetallic cooperative high-entropy nanoparticles also provide numerous active sites favoring redox kinetics of the sulfur electrode.The resulting selenium-doped HEO(AlCrFeCoNi)_(3)O_(4-x)-Se_(x)not only enhances discharge capacity but also maintains excellent capacity cycling stability.As a result,the HEO-Se/S composite exhibits a specific capacity of 1233.9 mAh g^(-1)at 0.1C and experiences minimal capacity fading at a rate of 0.038%per cycle over 500 cycles at 0.2C,while host materials with sulfur loading of 4.33 mg cm^(-2)and E/S ratio of 5.88μL mg^(-1)exhibit excellent capacity retention after 100 cycles at 0.2C.This work offers new insights into synthesizing high-entropy nanomaterials for improving the electrochemical performance of Li–S batteries.展开更多
A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields...A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields such as thermal barrier coatings,energy storage,dielectric materials,and transparent ceramics.However,there are limited reports on the dielectric properties of A_(2)B_(2)O_(7)high-entropy oxides.Consequently,further investigation is required to understand the polarization mechanisms in high-entropy ceramics and analyze the formation of oxygen vacancies and their influence.In the present study,La_(2)[(TiZrSnHfGe)_((1-2x)5)(NbGa)_(x)]_(2)O_(7)(x=0.129,0.143,0.157,0.171)(LTZSHGNGO)ceramics were synthesized successfully using a conventional solidstate reaction method.Compared withLa_(2)(TiZrSnHfGe)_(2)O_(7)ceramics,LTZSHGNGO demonstrated a nearly 6.7-fold increase in dielectric constant and a 33%reduction in dielectric loss.The incorporation of Nb/Ga enhanced the high-temperature dielectric properties and improved dielectric stability.The exceptional dielectric performance is primarily attributed to the synergistic highentropy effect,while Nb/Ga doping increased the number of oxygen vacancies and generated more defect dipole clusters[Ti^(4+)·e-V_(O)^(**)-Ti^(4+)·e].This study provides novel insights into the dielectric properties of LTZSHGNGO high-entropy ceramics and offers a novel approach to understanding the performance of A_(2)B_(2)O_(7)ceramics.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
High-entropy oxides(HEOs)have sparked scientific interest recently as a potential material technology for lithium-sulfur(Li–S)batteries.This interest stems from their simultaneous roles as sulfur hosts and electrocat...High-entropy oxides(HEOs)have sparked scientific interest recently as a potential material technology for lithium-sulfur(Li–S)batteries.This interest stems from their simultaneous roles as sulfur hosts and electrocatalysts,which provide enhancements to the performance of sulfur cathode composites.Nonetheless,their incorporation into the active material blend results in compromised energy density,particularly when their gravimetric proportion is substantial(≥10 wt.%,in the sulfur-based cathode).展开更多
Many catalysts have shown excellent activity for the sulfur reduction reaction(SRR),but sluggish electrochemistry kinetics have hindered the development of lithium-sulfur batteries.It has been found that the activity ...Many catalysts have shown excellent activity for the sulfur reduction reaction(SRR),but sluggish electrochemistry kinetics have hindered the development of lithium-sulfur batteries.It has been found that the activity of catalysts for the sulfur evolution reaction(SER)plays a crucial role in determining the overall reaction kinetics.To address this issue,the rational design of catalysts is crucial.Here,we proposed a popular rule to accelerate SER by using chip-like high-entropy perovskite oxide La_(0.7)Sr_(0.3)(Fe_(0.2)Co_(0.2)Ni_(0.2)Zn_(0.2)Mn_(0.2))O_(3-δ)(LMO-HEO)as advanced electrocatalysts.The strong interaction between the adjacent metal atoms in different metals of LMO-HEO electrocatalysts could lead to a"cocktail effect",which not only greatly improved the catalytic capacity toward sulfur species,but also accelerated the oxidation reaction kinetics of Li_2S.As a result,the S/La_(0.7)Sr_(0.3)(Fe_(0.2)Co_(0.2)Ni_(0.2)Zn_(0.2))Mn_(0.2)O_(3-δ)cathodes delivered excellent cyclic stability with a capacity decay of only 0.025%after 1200 cycles at 2 C.This work has provided a rational design idea for new multifunctional electrocatalysts with high catalytic capacity.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
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
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
Developing high-performance catalysts for dry reforming of methane(DRM)requires balancing activity,stability,and carbon resistance.Here,we reported a high-entropy oxide(HEO)nanosheet catalyst,(Mg_(0.4)Fe_(0.2)Co_(0.2)...Developing high-performance catalysts for dry reforming of methane(DRM)requires balancing activity,stability,and carbon resistance.Here,we reported a high-entropy oxide(HEO)nanosheet catalyst,(Mg_(0.4)Fe_(0.2)Co_(0.2)Ni_(0.2))Al_(2)O_(4),synthesized via a solvent-free citrate-assisted route,which achieved exceptional DRM performance.The HEO nanosheets exhibited outstanding activity at 750°C,with CH_(4)and CO_(2)conversions exceeding 89%and 92%,respectively,while maintaining stability for>400 h—far surpassing sol-gel-derived counterparts(CH_(4)/CO_(2)conversions<77%/84%within 6 h)and Ni-only catalysts(CH_(4)/CO_(2)<72%/81%in 14 h).Post-reduction,FeCoNi ternary alloy nanoparticles are exsolved from the HEO matrix,combining high metal dispersion with strong interfacial interactions.Density functional theory(DFT)calculations revealed that the upward shift of the d-band center in FeCoNi(-1.59 eV)compared to pure Ni(-2.42 eV)enhanced charge transfer to reactants,weakening C–H and C–O bonds.This electronic modulation,coupled with the nanosheet morphology,suppressed sintering and carbon deposition,as evidenced by negligible mass loss(98%retention)after 400 h.Raman and TEM analyses confirmed that the HEO nanosheets resisted graphitic carbon formation,unlike conventional catalysts plagued by fibrous coke.This work demonstrates how HEO-derived alloy catalysts synergize structural robustness and electronic optimization to advance DRM technology.展开更多
The lack of efficient and low-cost catalysts hinders the large-scale application of electrolytic water splitting.High-entropy oxides(HEOs)offer unique structures and promising properties for oxygen evolution reaction(...The lack of efficient and low-cost catalysts hinders the large-scale application of electrolytic water splitting.High-entropy oxides(HEOs)offer unique structures and promising properties for oxygen evolution reaction(OER)but are often synthesized via high-temperature methods,resulting in microscale particles with low active site exposure.HEO sub-1 nm nanosheets(SNSs)are synthesized using a cluster-nuclei co-assembly strategy with the introduction of phosphomolybdic acid(PMA)clusters.Molecular dynamics simulation results demonstrate that the PMA clusters act as linkers,facilitating the co-assembly of multimetal oxides into stable and ordered nanosheets via noncovalent interactions.Owing to the sub-nanoscale structure and precise elemental regulation,these SNSs demonstrate enhanced performance in OER.Among them,HEO-PMA SNSs demonstrated superior performance,achieving an overpotential of 229 mV at 10 mA cm^(-2)and exceptional long-term stability that lasted for over 1000 h at a large current density of 250 mA cm^(-2).Density functional theory calculations also demonstrate that the synergistic effect of multiple metals can significantly enhance the OER process.Composition engineering and sub-1 nm structural design in HEOs provide a promising strategy to enhance catalyst stability,addressing challenges related to low intrinsic activity,scarce active sites,and long-term durability in the OER process.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
基金financially supported by the National Natural Science Foundation of China(Grant No.12172093)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012607)。
文摘High-entropy oxides(HEOs)have emerged as a promising class of memristive materials,characterized by entropy-stabilized crystal structures,multivalent cation coordination,and tunable defect landscapes.These intrinsic features enable forming-free resistive switching,multilevel conductance modulation,and synaptic plasticity,making HEOs attractive for neuromorphic computing.This review outlines recent progress in HEO-based memristors across materials engineering,switching mechanisms,and synaptic emulation.Particular attention is given to vacancy migration,phase transitions,and valence-state dynamics—mechanisms that underlie the switching behaviors observed in both amorphous and crystalline systems.Their relevance to neuromorphic functions such as short-term plasticity and spike-timing-dependent learning is also examined.While encouraging results have been achieved at the device level,challenges remain in conductance precision,variability control,and scalable integration.Addressing these demands a concerted effort across materials design,interface optimization,and task-aware modeling.With such integration,HEO memristors offer a compelling pathway toward energy-efficient and adaptable brain-inspired electronics.
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supported by the National Natural Science Foundation of China(Nos.52372289 and 52102368)the Guangdong Special Fund for key Areas(No.20237DZX3042)+1 种基金the State Key Laboratory of New Ceramic Materials Tsinghua University(No.KF202415)the Shenzhen Stable Support Project.
文摘Recently,the strategy of tuning the dielectric parameters of absorbers for their excellent electromag-netic wave absorption(EMA)performance has attracted much attention.Among those candidates used for EMA application,high-entropy oxides(HEOs)can be implemented with this strategy due to their rich composition modulability.In this work,a series of implementation approaches varying from elemental design to structural modulation are employed to modulate the dielectric parameters of HEOs,resulting in their excellent EMA performance.The addition of Ti element optimizes the dipole distribution at the microscopic scales,improving the dielectric polarization of the materials.Moreover,a composite mate-rial is constructed by physically blending HEO with acetylene black(ACET),which significantly improves the macroscopic conduction loss of the material.The optimization of the dielectric genes of HEO/ACET is achieved with the blending effect and excellent EMA performance could be obtained.Among them,HEO with 17.5%ACET addition exhibits dual-band absorption,while Ti-HEO containing Ti element exhibits not only low-frequency absorption with reflection loss(RL)up to-29.81 dB at C-band but broadband absorption over 6 GHz as well as an optimal RL value up to-52.31 dB.In addition to the development of innovative EMA materials,this study offers a new perspective on how the EMA characteristics can be effectively regulated.
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the financial support from the National Natural Science Foundation of China(52171223)the Guangxi Science and Technology Major Project(No.AA24206007)。
文摘Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient catalysts due to their complementary elemental and structural properties.We developed a deposition in-situ reduction(D-ISR)approach for the rapid synthesis of single-phase medium/high-entropy oxides(M/HEOs)at room temperature,along with establishing general criteria for M/HEOs synthesis based on component properties.Deposition facilitates the incorporation of active elements(Ti/Zr/V/Cr/Nb),which significantly enhance the enthalpy-driven force of the dynamic oxidation(DO)process via an“active element coordination”strategy,thereby overcoming low-temperature solid solubility limitations.Nine-component HEOs and large-scale experiments confirm the universality and mass-production potential of the D-ISR approach.CoCuNiTi-O/AC synthesized via this strategy exhibits pronounced crystal distortion and disorder(Co–O coordination number=10.2),enhancing the Co–O coordination environment and mitigating Ostwald ripening.This leads to high activity and significantly enhanced structural stability,achieving a turnover frequency of 236.6 min^(-1)for ammonia borane hydrolysis,15 times higher than Co-O/AC and surpassing the most non-noble catalysts.These observations highlight an efficient M/HEOs synthesis methodology that advances M/HEMs applications in nanoenergy.
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 Jilin Province Science and Technology Development Project(Nos.20250102158JC,20240302035GX)
文摘As a novel material,high-entropy compounds have attracted extensive attention in the field of lithium–sulfur battery host materials due to their diverse elemental composition with a wide range of properties.The ability to effectively mitigate the shuttle effect of lithium polysulfides and catalyze the bidirectional conversion of Li_(2)S_(2)/Li_(2)S is crucial to enhance the overall performance of the battery.In this study,a unique sulfur host nanosized highentropy material comprising selenium-doped HEO(AlCrFeCoNi)_(3)O_(4-x)-Se_(x)is fabricated using an in situ thermal reduction and selenylation method.In the high-entropy compounds,the introduction of Se causes that the generation of oxygen vacancies during the lattice distortion serves as ion transfer pathway and the formation of M-Se bonds provides a high adsorption capability for LiPSs.Moreover,the polymetallic cooperative high-entropy nanoparticles also provide numerous active sites favoring redox kinetics of the sulfur electrode.The resulting selenium-doped HEO(AlCrFeCoNi)_(3)O_(4-x)-Se_(x)not only enhances discharge capacity but also maintains excellent capacity cycling stability.As a result,the HEO-Se/S composite exhibits a specific capacity of 1233.9 mAh g^(-1)at 0.1C and experiences minimal capacity fading at a rate of 0.038%per cycle over 500 cycles at 0.2C,while host materials with sulfur loading of 4.33 mg cm^(-2)and E/S ratio of 5.88μL mg^(-1)exhibit excellent capacity retention after 100 cycles at 0.2C.This work offers new insights into synthesizing high-entropy nanomaterials for improving the electrochemical performance of Li–S batteries.
基金financially supported by the National Natural Science Foundation of China(No.52201173)the S&T Program of Hebei(No.22567627H)+3 种基金the Natural Science Foundation of Hebei Province(No.E2021501017)Henan key Laboratory of Aeronautical Materials and Application Technology Open fund(No.ZHKF-230113)Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021301)the Fundamental Research Funds for the Central Universities(No.2024GFYD002,N2323021)
文摘A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields such as thermal barrier coatings,energy storage,dielectric materials,and transparent ceramics.However,there are limited reports on the dielectric properties of A_(2)B_(2)O_(7)high-entropy oxides.Consequently,further investigation is required to understand the polarization mechanisms in high-entropy ceramics and analyze the formation of oxygen vacancies and their influence.In the present study,La_(2)[(TiZrSnHfGe)_((1-2x)5)(NbGa)_(x)]_(2)O_(7)(x=0.129,0.143,0.157,0.171)(LTZSHGNGO)ceramics were synthesized successfully using a conventional solidstate reaction method.Compared withLa_(2)(TiZrSnHfGe)_(2)O_(7)ceramics,LTZSHGNGO demonstrated a nearly 6.7-fold increase in dielectric constant and a 33%reduction in dielectric loss.The incorporation of Nb/Ga enhanced the high-temperature dielectric properties and improved dielectric stability.The exceptional dielectric performance is primarily attributed to the synergistic highentropy effect,while Nb/Ga doping increased the number of oxygen vacancies and generated more defect dipole clusters[Ti^(4+)·e-V_(O)^(**)-Ti^(4+)·e].This study provides novel insights into the dielectric properties of LTZSHGNGO high-entropy ceramics and offers a novel approach to understanding the performance of A_(2)B_(2)O_(7)ceramics.
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financially supported by the National Natural Science Foundation of China(52372289 and 52102368)Guangdong Special Fund for Key Areas(20237DZX3042)+2 种基金State Key Laboratory of New Ceramic Materials Tsinghua University(No.KF202415)Shenzhen Stable Support Projectsupported by the Centre for Advances in Reliability and Safety(CAiRS)admitted under AIR@Inno HK Research Cluster and HK Poly U Postdoc Matching Fund Scheme(1-W28H)。
文摘High-entropy oxides(HEOs)have sparked scientific interest recently as a potential material technology for lithium-sulfur(Li–S)batteries.This interest stems from their simultaneous roles as sulfur hosts and electrocatalysts,which provide enhancements to the performance of sulfur cathode composites.Nonetheless,their incorporation into the active material blend results in compromised energy density,particularly when their gravimetric proportion is substantial(≥10 wt.%,in the sulfur-based cathode).
基金partially supported by grants from the National Natural Science Foundation of China(No.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Many catalysts have shown excellent activity for the sulfur reduction reaction(SRR),but sluggish electrochemistry kinetics have hindered the development of lithium-sulfur batteries.It has been found that the activity of catalysts for the sulfur evolution reaction(SER)plays a crucial role in determining the overall reaction kinetics.To address this issue,the rational design of catalysts is crucial.Here,we proposed a popular rule to accelerate SER by using chip-like high-entropy perovskite oxide La_(0.7)Sr_(0.3)(Fe_(0.2)Co_(0.2)Ni_(0.2)Zn_(0.2)Mn_(0.2))O_(3-δ)(LMO-HEO)as advanced electrocatalysts.The strong interaction between the adjacent metal atoms in different metals of LMO-HEO electrocatalysts could lead to a"cocktail effect",which not only greatly improved the catalytic capacity toward sulfur species,but also accelerated the oxidation reaction kinetics of Li_2S.As a result,the S/La_(0.7)Sr_(0.3)(Fe_(0.2)Co_(0.2)Ni_(0.2)Zn_(0.2))Mn_(0.2)O_(3-δ)cathodes delivered excellent cyclic stability with a capacity decay of only 0.025%after 1200 cycles at 2 C.This work has provided a rational design idea for new multifunctional electrocatalysts with high catalytic capacity.
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.
基金supported by the Program of Introducing Talents of Discipline to Universities(B23025)the Major Scientific and Technological Project of China Energy Engineering Corporation Limited(CEEC2021-ZDYF-02)+2 种基金the Key Research Program of Shaanxi Province(2022GXLH-01-08)the Shaanxi Province Qin Chuangyuan“Scientist+Engineer”Team(2022KXJ-179)the Targeted Funding Program of Power Construction Corporation of China(DJ-PTZX-2021-03)。
文摘Developing high-performance catalysts for dry reforming of methane(DRM)requires balancing activity,stability,and carbon resistance.Here,we reported a high-entropy oxide(HEO)nanosheet catalyst,(Mg_(0.4)Fe_(0.2)Co_(0.2)Ni_(0.2))Al_(2)O_(4),synthesized via a solvent-free citrate-assisted route,which achieved exceptional DRM performance.The HEO nanosheets exhibited outstanding activity at 750°C,with CH_(4)and CO_(2)conversions exceeding 89%and 92%,respectively,while maintaining stability for>400 h—far surpassing sol-gel-derived counterparts(CH_(4)/CO_(2)conversions<77%/84%within 6 h)and Ni-only catalysts(CH_(4)/CO_(2)<72%/81%in 14 h).Post-reduction,FeCoNi ternary alloy nanoparticles are exsolved from the HEO matrix,combining high metal dispersion with strong interfacial interactions.Density functional theory(DFT)calculations revealed that the upward shift of the d-band center in FeCoNi(-1.59 eV)compared to pure Ni(-2.42 eV)enhanced charge transfer to reactants,weakening C–H and C–O bonds.This electronic modulation,coupled with the nanosheet morphology,suppressed sintering and carbon deposition,as evidenced by negligible mass loss(98%retention)after 400 h.Raman and TEM analyses confirmed that the HEO nanosheets resisted graphitic carbon formation,unlike conventional catalysts plagued by fibrous coke.This work demonstrates how HEO-derived alloy catalysts synergize structural robustness and electronic optimization to advance DRM technology.
基金supported by the Hundred Talents Programs in the Chinese Academy of Sciencesthe Ningbo Yongjiang Talent Introduction Program(2021A-111-G)+2 种基金the Ningbo S&T Innovation 2025 Major Special Program(2022Z205)the Kunpeng Plan of Zhejiang Provincethe Ningbo Top Talent Program。
文摘The lack of efficient and low-cost catalysts hinders the large-scale application of electrolytic water splitting.High-entropy oxides(HEOs)offer unique structures and promising properties for oxygen evolution reaction(OER)but are often synthesized via high-temperature methods,resulting in microscale particles with low active site exposure.HEO sub-1 nm nanosheets(SNSs)are synthesized using a cluster-nuclei co-assembly strategy with the introduction of phosphomolybdic acid(PMA)clusters.Molecular dynamics simulation results demonstrate that the PMA clusters act as linkers,facilitating the co-assembly of multimetal oxides into stable and ordered nanosheets via noncovalent interactions.Owing to the sub-nanoscale structure and precise elemental regulation,these SNSs demonstrate enhanced performance in OER.Among them,HEO-PMA SNSs demonstrated superior performance,achieving an overpotential of 229 mV at 10 mA cm^(-2)and exceptional long-term stability that lasted for over 1000 h at a large current density of 250 mA cm^(-2).Density functional theory calculations also demonstrate that the synergistic effect of multiple metals can significantly enhance the OER process.Composition engineering and sub-1 nm structural design in HEOs provide a promising strategy to enhance catalyst stability,addressing challenges related to low intrinsic activity,scarce active sites,and long-term durability in the OER process.
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.
