Advances in developing high entropy alloys and ceramics with improved physical properties have greatly broadened their application field from aerospace industry,public transportation to nuclear plants.In this review,w...Advances in developing high entropy alloys and ceramics with improved physical properties have greatly broadened their application field from aerospace industry,public transportation to nuclear plants.In this review,we describe the concept of entropy engineering as applicable to inorganic non-metallic glasses,especially for tailoring and enhancing their mechanical,electrical,and optical properties.We also present opportunities and challenges in calculating entropy of inorganic non-metallic glass systems,correlating entropy to glass formation,and in developing functional inorganic non-metallic glasses via the entropy concept.展开更多
Entropy engineering has emerged as an effective strategy for improving the figure-of-merit zT by decelerating the phonon transport while maintaining good electrical transport properties of thermoelectric materials.Her...Entropy engineering has emerged as an effective strategy for improving the figure-of-merit zT by decelerating the phonon transport while maintaining good electrical transport properties of thermoelectric materials.Herein,a high average zT of 1.54 and a maximum zT of 2.1 are achieved in the mid-entropy GeTe constructed by Ag,Sb,and Pb alloying.At room temperature,the mid-entropy GeTe tends to be a cubic structure.And the power factor is improved from 7.7μW·cm^(-1)·K^(-2) to 16.2μW·cm·cm^(-1)·K^(-2) due to the large increase in effective mass and the optimized carrier concentration.The increasing disorder created by heavy and off-centering Ag,Sb,and Pb atoms induces strong mass/strain fluctuations and phonon scattering to decelerate the phonon transport in GeTe.A low lattice thermal conductivity is obtained in the medium-entropy GeTe-based material.Moreover,a GeTe-based thermoelectric cooler is fabricated with the cooling temperature difference of 66.6 K with the hot end fixed at 363 K.This work reveals the effectiveness of entropy engineering in improving the average zT in GeTe and shows potential application of GeTe as a thermoelectric cooler.展开更多
The compositional flexibility and structural stability of SrTiO_(3)-based perovskite oxides present a promising approach to tailor their electrical and thermal transport properties.In this work,a series of(Ca_(0.25)Nd...The compositional flexibility and structural stability of SrTiO_(3)-based perovskite oxides present a promising approach to tailor their electrical and thermal transport properties.In this work,a series of(Ca_(0.25)Nd_(0.25)Sr_(0.35)Ba_(0.15))1-xTiO_(3)±δceramics with varying A-site deficiencies were designed by integrating entropy engineering and defect chemistry,and their microstructural characteristics and transport properties were systematically investigated.All samples exhibited a stable single-phase Pm3m cubic structure with uniformly distributed constituent elements.The introduction of A-site vacancies created favorable pathways for ion diffusion during the sintering process and facilitated grain growth.A-site deficiencies significantly increased carrier concentration by promoting the formation of oxygen vacancies and Ti^(3+),while also enhancing carrier mobility by improving structural symmetry and reducing grain boundary scattering,leading to the improved power factor.The multiscale defects resulting from entropy engineering including point defects,strain fields,and high-density grain boundaries contributed to the reduced thermal conductivity of all samples.By synergistically optimizing the entropy and defect engineering,the sample with x=0.09 achieved a peak figure of merit(ZT)of 0.21 at 900 K,representing a 32%enhancement compared with that of the x=0.03 sample.This work underscores the significance of the combined strategy of entropy engineering and defect chemistry in manipulating the transport properties of SrTiO_(3)-based thermoelectric oxides.展开更多
High-entropy structures in layered compounds,especially transitional metal dichalcogenides(TMDCs),have powered the field with disordered and versatile chemical compositions,showing great potential in various functiona...High-entropy structures in layered compounds,especially transitional metal dichalcogenides(TMDCs),have powered the field with disordered and versatile chemical compositions,showing great potential in various functional applications,including energy storage and catalysis.However,the reported high-entropy phases are mainly 1T phases,2H phases are rare,and approximately 3R phases are still lacking.Here,phase engineering of high-entropy TMDCs is achieved by tuning the chemical composition of(Mo_(0.5)W_(0.5))_(1−x)(Nb_(0.5)Ta_(0.5))_(x)Se_(2+δ),0≤x<1,and−0.1≤δ≤0.3.A phase diagram is constructed to guide the synthesis of pure 2H/3R phases over a wide composition/entropy range.The increase in VB-group element content and Se overdose facilitated the formation of 3R phases,whereas the opposite occurred for 2H phases.Thermodynamic first-principles calculations evaluate the stability of phases in different polytypes and compositions,matching well with the composition-dependent crystalline habits.Moreover,the optimized thermoelectric performance,with a figure of merit(zT=0.36@723 K)in 2H phase of x=0.2,is attributed to the low thermal conductivity(κ)caused by the high-entropy effect,which is one of the highest among(Mo/W)Se_(2)-based materials.Our work enriches high-entropy TMDCs with versatile polytypes,expanding their potential uses for various fields.展开更多
Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive c...Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive chlorine evolution,and chloride corrosion or poisoning problems,needing to develop high-efficient and robust electrocatalysts toward those challenges.Herein,novel defect-rich single-phase(NiCoMnCrFe)_(3)O_(4) high-entropy spinel oxide(HEO)is fabricated by low-temperature annealing of highentropy layered double hydroxide precursor.Due to the presence of abundant defects,unique“cocktail”effect,and efficient electronic structure regulation,such(NiCoMnCrFe)_(3)O_(4) can deliver 500 mA cm^(−2) current density at the overpotentials of 268/384 mV in alkaline freshwater/seawater,outperforming its counterparts,commercial IrO_(2),and most reported OER catalysts.Moreover,it manifests exceptional OER durability and anticorrosion capability.Theoretical calculations reveal that the eg occupancies of surface Mn atoms are closer to 1.0,which may be the activity origin of such HEO.Importantly,the constructed(NiCoMnCrFe)_(3)O_(4)||Pt/C electrolyzer only requires 1.57 V cell voltage for driving overall seawater splitting to reach 500 mA cm^(−2) current under real industrial conditions.This work may spur the development of advanced OER electrocatalysts by combining entropy and defect engineering and accelerate their applications in seawater splitting,metal–air batteries,or marine biomass electrocatalytic conversion fields.展开更多
The thermoelectric(TE)performance of p-type ZrCoSb-based half-Heusler(HH)alloys has been improved tremendously in recent years;however,it remains challenging to find suitable n-type ZrCoSb-based HH alloys due to their...The thermoelectric(TE)performance of p-type ZrCoSb-based half-Heusler(HH)alloys has been improved tremendously in recent years;however,it remains challenging to find suitable n-type ZrCoSb-based HH alloys due to their high lattice thermal conductivity(κ_(L)).In this work,n-type Zr_(1−x)Ta_(x)Co_(1−x)Ni_(x)Sb HH alloys were firstly designed by multisite alloying.The evolution of the Raman peak proved that alloy scattering,phonon softening,anharmonicity,entropy-driven disorder,and precipitates had a combined effect on decreasingκ_(L)by 46.7%compared to that of pristine ZrCoSb.Subsequently,Hf_(0.75)Zr_(0.25)NiSn_(0.99)Sb_(0.01)was introduced into Zr_(0.88)Ta_(0.12)Co_(0.88)Ni_(0.12)Sb to further suppressκ_(L).Remarkably,the grain size of the biphasic HH alloys was refined by at least one order of magnitude.A biphasic high-entropy HH alloy with y=0.2 exhibited the minimumκ_(L)of∼2.44 W/(m·K)at 923 K,reducing by 67.7%compared to that of ZrCoSb.Consequently,(Zr_(0.88)Ta_(0.12)Co_(0.88)Ni_(0.12)Sb)_(0.9)(Hf_(0.75)Zr_(0.25)NiSn_(0.99)Sb_(0.01))_(0.1)exhibited the highest TE figure of merit(∼0.38)at 923 K.The cooperation between the entropy and biphasic microstructure resulted in multiscale defects,refined grains,and biphasic interfaces,which maximized the scattering of the multiwavelength phonons in HH alloys.This work provides a new strategy for further reducing the grain size andκ_(L)of medium-and high-entropy HH alloys.展开更多
无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_...无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_(0.5)(0.01≤x≤0.06)块体热电材料.随着Se和Mn的引入,体系由低熵Cu_(1.8)S(0.4R^(*))转变为中熵MnxCu_(1.8)S_(0.5)Se_(0.5)(1.2R^(*)).构型熵的增加不仅提高了体系的结构对称性,MnxCu_(1.8)S_(0.5)Se_(0.5)室温下呈立方相结构,还增大了Mn的固溶度.高浓度Mn固溶有效填补了过高的本征Cu空位,降低了载流子浓度,优化了能带结构,提升了电输运性能.熵工程一方面增大了Cu离子迁移势垒,抑制Cu离子迁移.750 K下,即使电流密度达到24 A cm^(-2),Mn_(0.03)Cu_(1.8)S_(0.5)Se_(0.5)的电阻也几乎没有变化,显示出优异的电稳定性;同时可降低声速,软化晶格,降低晶格热导率.Mn_(0.06)Cu_(1.8)S_(0.5)Se_(0.5)的块体样品在773 K时获得最大ZT值0.79,相较于初始样品提高了两倍.结果表明熵工程结合Cu空位工程是提升Cu_(1.8)S基热电材料性能的有效策略.展开更多
基金financial support from the National Key Research and Development Program of China(Grant No.2020YFB1805901)the National Science Fund for Distinguished Young Scholars(Grant No.62125502)+5 种基金the National Natural Science Foundation of China(Grant No.51972113)the Key Program of Guangzhou Scientific Research Special Project(Grant No.201904020013)the Key Research and Development Program of Guangzhou(Grant No.202007020003)the Science and Technology Project of Guangdong Province(Grant No.2021A0505030004)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2017BT01×137)the Fundamental Research Funds for the Central University.
文摘Advances in developing high entropy alloys and ceramics with improved physical properties have greatly broadened their application field from aerospace industry,public transportation to nuclear plants.In this review,we describe the concept of entropy engineering as applicable to inorganic non-metallic glasses,especially for tailoring and enhancing their mechanical,electrical,and optical properties.We also present opportunities and challenges in calculating entropy of inorganic non-metallic glass systems,correlating entropy to glass formation,and in developing functional inorganic non-metallic glasses via the entropy concept.
基金This work is supported by the National Natural Science Foundation of China(Grant No.52222209,11934007,and 52302262)the Science and Technology Innovation Committee Foundation of Shenzhen(Grant No.JCYJ20220530165000001)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(Grant No.2021QNRC001)the Outstanding Talents Training Fund in Shenzhen(202108)the Natural Science Foundation of Sichuan(Grant No.2023NSFSC0953).
文摘Entropy engineering has emerged as an effective strategy for improving the figure-of-merit zT by decelerating the phonon transport while maintaining good electrical transport properties of thermoelectric materials.Herein,a high average zT of 1.54 and a maximum zT of 2.1 are achieved in the mid-entropy GeTe constructed by Ag,Sb,and Pb alloying.At room temperature,the mid-entropy GeTe tends to be a cubic structure.And the power factor is improved from 7.7μW·cm^(-1)·K^(-2) to 16.2μW·cm·cm^(-1)·K^(-2) due to the large increase in effective mass and the optimized carrier concentration.The increasing disorder created by heavy and off-centering Ag,Sb,and Pb atoms induces strong mass/strain fluctuations and phonon scattering to decelerate the phonon transport in GeTe.A low lattice thermal conductivity is obtained in the medium-entropy GeTe-based material.Moreover,a GeTe-based thermoelectric cooler is fabricated with the cooling temperature difference of 66.6 K with the hot end fixed at 363 K.This work reveals the effectiveness of entropy engineering in improving the average zT in GeTe and shows potential application of GeTe as a thermoelectric cooler.
基金supported by the National Natural Science Foundation of China(No.52130203)the Natural Science Foundation of Shandong Province(No.ZR2022QB159).
文摘The compositional flexibility and structural stability of SrTiO_(3)-based perovskite oxides present a promising approach to tailor their electrical and thermal transport properties.In this work,a series of(Ca_(0.25)Nd_(0.25)Sr_(0.35)Ba_(0.15))1-xTiO_(3)±δceramics with varying A-site deficiencies were designed by integrating entropy engineering and defect chemistry,and their microstructural characteristics and transport properties were systematically investigated.All samples exhibited a stable single-phase Pm3m cubic structure with uniformly distributed constituent elements.The introduction of A-site vacancies created favorable pathways for ion diffusion during the sintering process and facilitated grain growth.A-site deficiencies significantly increased carrier concentration by promoting the formation of oxygen vacancies and Ti^(3+),while also enhancing carrier mobility by improving structural symmetry and reducing grain boundary scattering,leading to the improved power factor.The multiscale defects resulting from entropy engineering including point defects,strain fields,and high-density grain boundaries contributed to the reduced thermal conductivity of all samples.By synergistically optimizing the entropy and defect engineering,the sample with x=0.09 achieved a peak figure of merit(ZT)of 0.21 at 900 K,representing a 32%enhancement compared with that of the x=0.03 sample.This work underscores the significance of the combined strategy of entropy engineering and defect chemistry in manipulating the transport properties of SrTiO_(3)-based thermoelectric oxides.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0470303)the National Nature Science Foundation of China(No.52473295)+1 种基金the Young Elite Scientists Sponsorship Program by CAST(No.2024QNRC001)the State Key Laboratory of Structural Chemistry(No.20230020).
文摘High-entropy structures in layered compounds,especially transitional metal dichalcogenides(TMDCs),have powered the field with disordered and versatile chemical compositions,showing great potential in various functional applications,including energy storage and catalysis.However,the reported high-entropy phases are mainly 1T phases,2H phases are rare,and approximately 3R phases are still lacking.Here,phase engineering of high-entropy TMDCs is achieved by tuning the chemical composition of(Mo_(0.5)W_(0.5))_(1−x)(Nb_(0.5)Ta_(0.5))_(x)Se_(2+δ),0≤x<1,and−0.1≤δ≤0.3.A phase diagram is constructed to guide the synthesis of pure 2H/3R phases over a wide composition/entropy range.The increase in VB-group element content and Se overdose facilitated the formation of 3R phases,whereas the opposite occurred for 2H phases.Thermodynamic first-principles calculations evaluate the stability of phases in different polytypes and compositions,matching well with the composition-dependent crystalline habits.Moreover,the optimized thermoelectric performance,with a figure of merit(zT=0.36@723 K)in 2H phase of x=0.2,is attributed to the low thermal conductivity(κ)caused by the high-entropy effect,which is one of the highest among(Mo/W)Se_(2)-based materials.Our work enriches high-entropy TMDCs with versatile polytypes,expanding their potential uses for various fields.
基金supported by the National Natural Science Foundation of China(21671106,22102073,and 62288102)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the funding from Minjiang Scholars Award Program(2023)+1 种基金the Start-Up Fund for High-Leveled Talents from Fujian Normal University(Y0720316K13)the opening research foundations of the State Key Laboratory of Coordination Chemistry,Nanjing National Laboratory of Solid State Microstructures,Nanjing University.We thank the BL14W1 beamlines for XAFS tests at the Shanghai Synchrotron Radiation Facility(SSRF)(Shanghai,China).
文摘Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive chlorine evolution,and chloride corrosion or poisoning problems,needing to develop high-efficient and robust electrocatalysts toward those challenges.Herein,novel defect-rich single-phase(NiCoMnCrFe)_(3)O_(4) high-entropy spinel oxide(HEO)is fabricated by low-temperature annealing of highentropy layered double hydroxide precursor.Due to the presence of abundant defects,unique“cocktail”effect,and efficient electronic structure regulation,such(NiCoMnCrFe)_(3)O_(4) can deliver 500 mA cm^(−2) current density at the overpotentials of 268/384 mV in alkaline freshwater/seawater,outperforming its counterparts,commercial IrO_(2),and most reported OER catalysts.Moreover,it manifests exceptional OER durability and anticorrosion capability.Theoretical calculations reveal that the eg occupancies of surface Mn atoms are closer to 1.0,which may be the activity origin of such HEO.Importantly,the constructed(NiCoMnCrFe)_(3)O_(4)||Pt/C electrolyzer only requires 1.57 V cell voltage for driving overall seawater splitting to reach 500 mA cm^(−2) current under real industrial conditions.This work may spur the development of advanced OER electrocatalysts by combining entropy and defect engineering and accelerate their applications in seawater splitting,metal–air batteries,or marine biomass electrocatalytic conversion fields.
基金supported by the National Natural Science Foundation of China(Grant Nos.52271025,51971052,51927801,51834009)the Liaoning Revitalization Talents Program(No.XLYC2007183).
文摘The thermoelectric(TE)performance of p-type ZrCoSb-based half-Heusler(HH)alloys has been improved tremendously in recent years;however,it remains challenging to find suitable n-type ZrCoSb-based HH alloys due to their high lattice thermal conductivity(κ_(L)).In this work,n-type Zr_(1−x)Ta_(x)Co_(1−x)Ni_(x)Sb HH alloys were firstly designed by multisite alloying.The evolution of the Raman peak proved that alloy scattering,phonon softening,anharmonicity,entropy-driven disorder,and precipitates had a combined effect on decreasingκ_(L)by 46.7%compared to that of pristine ZrCoSb.Subsequently,Hf_(0.75)Zr_(0.25)NiSn_(0.99)Sb_(0.01)was introduced into Zr_(0.88)Ta_(0.12)Co_(0.88)Ni_(0.12)Sb to further suppressκ_(L).Remarkably,the grain size of the biphasic HH alloys was refined by at least one order of magnitude.A biphasic high-entropy HH alloy with y=0.2 exhibited the minimumκ_(L)of∼2.44 W/(m·K)at 923 K,reducing by 67.7%compared to that of ZrCoSb.Consequently,(Zr_(0.88)Ta_(0.12)Co_(0.88)Ni_(0.12)Sb)_(0.9)(Hf_(0.75)Zr_(0.25)NiSn_(0.99)Sb_(0.01))_(0.1)exhibited the highest TE figure of merit(∼0.38)at 923 K.The cooperation between the entropy and biphasic microstructure resulted in multiscale defects,refined grains,and biphasic interfaces,which maximized the scattering of the multiwavelength phonons in HH alloys.This work provides a new strategy for further reducing the grain size andκ_(L)of medium-and high-entropy HH alloys.
基金supported by the National Key R&D Program of China(2018YFB0703603)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(KF202111)。
文摘无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_(0.5)(0.01≤x≤0.06)块体热电材料.随着Se和Mn的引入,体系由低熵Cu_(1.8)S(0.4R^(*))转变为中熵MnxCu_(1.8)S_(0.5)Se_(0.5)(1.2R^(*)).构型熵的增加不仅提高了体系的结构对称性,MnxCu_(1.8)S_(0.5)Se_(0.5)室温下呈立方相结构,还增大了Mn的固溶度.高浓度Mn固溶有效填补了过高的本征Cu空位,降低了载流子浓度,优化了能带结构,提升了电输运性能.熵工程一方面增大了Cu离子迁移势垒,抑制Cu离子迁移.750 K下,即使电流密度达到24 A cm^(-2),Mn_(0.03)Cu_(1.8)S_(0.5)Se_(0.5)的电阻也几乎没有变化,显示出优异的电稳定性;同时可降低声速,软化晶格,降低晶格热导率.Mn_(0.06)Cu_(1.8)S_(0.5)Se_(0.5)的块体样品在773 K时获得最大ZT值0.79,相较于初始样品提高了两倍.结果表明熵工程结合Cu空位工程是提升Cu_(1.8)S基热电材料性能的有效策略.
